University of Wollongong
Research Online
University of Wollongong Thesis Collection
University of Wollongong Thesis Collections
2013
Valuing native plantation monocultures in
Australia: the relationship between faunal richness
and environment in Eucalypt plantations
Beth Mott
University of Wollongong
Research Online is the open access institutional repository for the
University of Wollongong. For further information contact the UOW
Library: [email protected]
Valuing native plantation monocultures in
Australia: the relationship between faunal
richness and environment in Eucalypt plantations
A thesis submitted in fulfillment of the requirements for the award of the degree
Doctor of Philosophy
from
The University of Wollongong
by
Beth Mott, B. Sc. (Hons)
School of Biological Sciences
2013
CERTIFICATION
I, Beth Mott, declare that this thesis, submitted in fulfilment of the requirements
for the award of Doctor of Philosophy, in the School of Biological Sciences,
University of Wollongong, is wholly my own work unless otherwise referenced or
acknowledged.
The chapters in this thesis constitute original research carried out by
myself during the period of candidature. I was the main contributor of the study
design, and was solely responsible for data collection. I wrote the first draft of
each manuscript and was responsible for responding to the editorial suggestions
of those asked to comment on manuscripts.
The document has not been submitted for qualifications at any other academic
institution.
Beth Mott
July 2013.
Table of Contents
Abstract…………………………………………………………………………………
xii
Acknowledgements……………………………………………………………………
xvi
Chapter 1: The conservation value of native tree plantations for wildlife
Introduction……………………………….…………………….……………………...
1
Methods………………………………………………………………………..……....
6
Data extraction……...……………………...….………………………...…….
6
Data Analysis…...……………………………………………………...……..……….
9
Results………………………………………………………………………………….
13
Discussion……………………………………………………………………..………
18
Continuing work in context……………………………………………………..…….
23
Chapter 2: The relationship between thermal and structural characteristics
in managed forests: implications for microclimate diversity
Introduction……………………………….…………………….……………………...
26
Methods………………………………………………………………………..……....
28
Study area…………………………………..……………………………………...
28
Forest types………………………………………………..…………………………..….
29
Vegetation structure……………………………………………………………….
34
Thermal environment……………………………………………………………...
35
Data Analysis………………………………………………………………………
38
Results………………………………………………………..………...……..……….
40
Vegetation structure……………………………………………………………….
40
Environmental temperature………………………………………………………
41
Age related thermal differences within plantations…………………………….
42
Relating vegetation structure and thermal environment………………………
46
Discussion……………………………………………………………………………...
47
Vegetation structure……………………………………………………………….
48
i
Environmental temperature………………………………………………………
49
Plantation aging and effects on environmental temperature………………….
52
Management recommendations and research…………………………………
53
Chapter 3: Faunal response to young afforested and old reforested
Eucalypt plantations: do consistent patterns exist across animal taxa?
Introduction……………………………….…………………….……………………...
55
Methods………………………………………………………………………..……....
57
Habitat descriptions………………………..……………………………………...
58
Sampling methodologies………………………………..…………………………..….
59
Species characteristics..………………………………………………………….
62
Data Analysis………………………………………………………………………
63
Results………………………………………………………..………...……..……….
64
Birds…………………………………………………………………………………
66
Herpetofauna………………………………………………………………………
67
Mammals…………………………………………………………………………...
68
Cross-taxa comparisons of guild structure……………………………………...
69
Discussion……………………………………………………………………………...
71
Patterns of richness……………………………………………………………….
71
Assemblage structure and ecological function…………………………………
73
Birds……………………………………………………………..………………….
74
Ground fauna………………………………………………………………………
76
The role of plantations in offsetting species loss……………………………….
77
Chapter 4: The influence of invertebrate resource heterogeneity on small
ground-dwelling vertebrates
Introduction……………………………….…………………….……………………...
80
Prey availability………………………………………………………………………..
81
Predators, prey and plantations……………………………………………………..
82
Methods………………………………………………………………………..……....
84
ii
Invertebrate sampling……………………..…………….………………………...
84
Invertebrate hardness………………………..………..…………………………..….
86
Relating predators and prey……………………………………………………...
87
Data Analysis………………………………………………………………………
91
Results………………………………………………………..………...……..……….
92
Insectivores…………………………………………………………………………
92
Invertebrate prey……………………………………………………………………
94
Discussion……………………………………………………………………………...
97
Predator abundance……………...……………………………………………….
98
Small predators……………………………...…………………………………
98
Medium predators…………………………………………..………………….
100
Large predators..………………………………………………………………
101
Grazing…………………………………………….……………………………….
102
Conclusions……………………………………………………………………………
103
Chapter 5: Matrix quality and ground fauna diversity in young plantations
Young native plantations in the landscape mosaic…..…….……………………...
105
The matrix and matrix quality.………………………………………………………..
106
Methods………………………………………………………………………..……....
110
Habitat descriptions……………………..…………….………………………......
110
Vegetation structure………………………..………..…………………………..……...
112
Fauna trapping..…………………….……………………………………………..
113
Data Analysis………………………………………………………………………
115
Results………………………………………………………..………...……..……….
116
Vegetation structure….……………………………………………….……………
116
Fauna…….…….……………………………………………………………………
117
Discussion……………………………………………………………………………...
120
Matrix quality……….……………...……………………………………………….
120
The effects of grazing on plantations.…...………..…………………………
120
Age structure……...……………………………………………………………
122
Conclusions……………………………………………………………………………
123
iii
Chapter 6: The relative roles of structure and thermal environment in
determining habitat choice by lizards in young plantations
Introduction……………………………….…………………….……………………...
125
Thermal environment and habitat choice……...………………………………..
126
Thermal physiology of reptiles...………………………..………………………..
127
Constraints of plantation environments on lizards……………………………..
128
Methods………………………………………………………………………..……....
131
Habitat choice enclosures………………..………..…………………………..….
132
Data analysis….………………………………………………………..
137
Results……………..…………………………………………………...
138
Feeding study………………………………………………………………….
143
Data analysis…………………………………………………………...
145
Results………………………………………………………………….
146
Discussion……………………………………………………………………………...
157
Preferred temperature range and habitat specialization………………………
157
Substrate preference and habitat choice………………………………………..
159
Rates of digestion….…………………………………………..………………….
161
Conclusions……………………………………………………………………………
164
Chapter 7: General Discussion
The value of plantations as habitat – an overview.…..…….……………………...
166
This research in context.……………………………………………………………..
167
Woodland birds.……………………..…………….………………………......
169
Forest species…………………………..………..…………………………..……...
171
Small mammals..….…………….……………………………………………..
172
Food availability……………………………………………..………...……..……….
173
Matrix quality…………….……………………………………………….……………
174
Plantations and the thermal environment…………………………………………..
177
Plantations and climate change……………………………………………………..
178
The way forward……………………………………………………………………….
179
iv
Conclusions……………………………………………………………………………
183
References…………………………………………………………………………..
185
v
List of Tables
Table 1.1 Studies examined in this meta-analysis comparing forests and native
plantations………………………………………………………..……………..
7
Table 1.2 Q tests for meta-analyses testing for differences in effect sizes (E+)
with changes in species richness and abundance between forests and
16
plantations…………………………………………………………………………..
Table 2.1 Vegetation parameters and the methods used to record them from four
forest types on the Mid North Coast of NSW………………..………………….
36
Table 2.2 Results of RMANOVA of change in environmental temperature with
forest type …………………...…………………………………….………………..
43
Table 2.3 Results of ANOVA and regression analyses relating vegetation
structure to solar radiation and environmental temperature levels……………
45
Table 3.1 Means (± 1se) of vegetation variables sampled from replicated 15m2
quadrats in old growth native forest, logged native forest, old and young
plantations……………………………………………………………………… ….
59
Table 3.2 Results of ANOSIM analysis comparing assemblage structure in four
eucalypt forest types for four vertebrate taxa on the mid north coast of New
South Wales, Australia……………………………….……………………………
66
Table 3.3 ANOVA results comparing the richness, abundance and habitat
specialization of birds, mammals and herpetofauna sampled in the study
area………………………………………………………..….………..……..……..
67
Table 3.4 Results of ANOSIM analysis comparing the distribution of feeding
guilds in four eucalypt forest types for birds, mammals and herpetofauna….
71
vi
Table 3.5 Summary of the ecological character of birds, mammals, reptiles and
frogs in eucalypt plantations on the mid-north coast of New South Wales…..
75
Table 4.1 Mean gape size and prey length category used by each predator
species sampled……………………………………………………………………
88
Table 4.2 ANOSIM results testing for changes in small medium and large
insectivore abundance in forests and plantations…….. ……………………….
93
Table 4.3 Results of χ2 analyses and associated pairwise comparisons for
changes in the frequency of preferred, available and unavailable prey
between forest types ……………………………………………………….……..
95
Table 5.1 Vegetation variables measured to quantify structural differences
between grazed native forest and young native plantation……………….……
113
Table 5.2 Results of paired t-tests for changes in vegetation structure between
grazed native eucalyptus woodland and adjacent native plantations…..…….
117
Table 5.3 Results of paired t-tests for changes in the richness and abundance of
reptile and mammal assemblages in plantations and native forests………….
118
Table 6.1 Body temperatures and habitat associations of target species in
experimental choice boxes on the Mid North Coast of New South Wales…...
139
Table 6.2 Results of mixed model analysis for change in body temperature with
position in experimental choice boxes……………………………………………
140
Table 6.3 Estimates of fixed effects for mixed models analysis of appetite and gut
passage rate from laboratory experiments for each lizard species…………...
156
vii
List of Figures
Fig 1.1 Forest plots of standardized differences in species richness and
abundance between forests and native plantations......................................
17
Fig. 2.1 A map of the study 50 x 80km study area on the Mid North Coast of
NSW……………………………………………………………………………….
31
Fig 2.2 Diagrammatic representation of the structural complexity of vegetation in
plantations…………………………………………………………………………
32
Fig 2.3 Principal co-ordinates biplot showing the distribution of vegetation
variables in relation to forest types…………………………………………….
42
Fig 2.3 Circadian profiles for mean environmental temperatures available in the
shade and sun throughout the course of the day from 6am to 6pm, in each
of four forest types……………………………………………………………….
44
Fig 2.4 Circadian profiles for mean environmental temperatures available in
early maturity and young plantations in the sun and shade throughout the
course of a day…….……………………………………………………………..
45
Fig 2.5 Scatter plots depicting the relationship of radiant energy/ environmental
temperature variables with vegetation variables………………………………
47
Fig 3.1 Species richness of birds, mammals and herpetofauna sampled from
forest and plantation sites on the Mid North Coast of NSW in 2001………..
65
Fig 3.2 Mean species richness and abundance of vertebrate taxa grouped by
habitat preference……………………………………………….………………..
68
viii
Fig 3.3 Distribution of mammal, reptile, bird and frog feeding guilds between
forest types………………………………………………………………………..
70
Fig 4.1 Cumulative abundances of small medium and large insectivores
sampled from old growth and logged native, and old and young native
plantations on the Mid North Coast of New South Wales………………..…..
93
Fig 4.2 The frequency of preferred, available and unavailable prey present in
each forest type for each predator group…………………………………….
96
Fig 5.1 Two six-year-old hardwood plantations showing typical connection to
other landscape elements……………………………………………………….
108
Fig 5.2 Mean abundance of forest, woodland and generalist fauna and the age
structure of samples populations in grazed woodland and adjacent young
119
native plantations…………………………………………………………………
Fig 6.1 Choice enclosures in situ on the Mid North Coast of NSW. A. Large
enclosures; B. Diagrammatic representation of the relative amount of
ambient radiant energy and substrate present in each compartment. C.
An example of the complex (left) and simple (right) substrates lizards
could select………………………………………………………………………
134
Fig 6.2 Diurnal profiles of levels of insolation and environmental temperatures
available to lizards in field enclosures throughout the course of the day;
with preferred temperature range overlaid on available
temperatures ……………………………………………………………………
141
Fig 6.3 Thermal profiles of available environmental temperatures in young
plantation habitats, overlaid by mean preferred temperature ranges of
‘hot’ and ‘cold’ lizards.………………………………………………………….
142
Fig 6.4 Appetite and gut passage rates of for the four species tested
ix
experimentally at (200C) spring, (250C) spring-summer and summer
(300C) temperatures available in young plantations on the Mid North
coast of New South Wales…………………………………………………….
156
x
List of Appendices
Appendix 1:
Table 1 Summary statistics and species list for all bird species recorded in the
trapping period between 2001 and 2003 from the North Coast
Bioregion…………………………………………………………………………..…226
Table 2 Summary statistics and species list for all mammal, frog and reptile
species caught in the trapping period between 2001 and 2003 from the
North Coast Bioregion………………..…………………………………………….227
Appendix 2
Summary statistics for all herpetofaunal and mammal species recorded
from young and old plantations, logged and old growth native forests
in twenty field sites on the Mid-North Coast of NSW between 2002 2003…………………………………………………………………………………. 228
Appendix 3
Summary statistics for all herpetofaunal and mammal species recorded from
young plantations and adjacent native forests ten field sites on the Mid-North
Coast of NSW between 2002 and 2004…………………………………………..229
xi
Abstract
Native forests throughout the world are disappearing at rate of
approximately 13 million hectares a year. One of the ways forest managers are
attempting to halt deforestation is by growing trees in plantations to provide
wood products. Industrial tree plantations will occupy 10-20% of the total
forested land area in the world by 2024. Research into the suitability of
plantations for wildlife has grown rapidly in the last fifteen years, but it has
focused primarily on exotic plantations. Comparatively little work has focused on
native tree plantations, which may better benefit biodiversity in forested
landscapes if they act like forests. A literature review of existing work identified
that age, size, level of management and the type of forest adjacent to
plantations can all affect the diversity of faunal assemblages using native
plantations, and that monocultures are generally species poor. This thesis
extends the small existing body of work on managed native plantations by
comparing faunal use of young and old native plantations with logged and old
growth native forests in the North Coast Bioregion of sub-tropical south-eastern
Australia. This thesis used trapping to identify whether birds, mammals, and
herpetofauna used plantations differently from forests, and ecophysiology,
landscape and community ecology theories to explain why they do so.
Plantations collectively, differed from forests in vegetation structure and
available microclimate at the ground level. The open canopy and lack of sub
xii
canopy complexity in young and old plantations resulted in higher insolation at
the ground in plantations, which increased environmental temperature up to
200C above that of old growth native forests in summer during the day. Young
plantations particularly presented a challenging environment to potential
colonizers sensitive to microclimate. Large daily fluctuations in temperature and
irradiance, coupled with the residual effects of management-associated soil
compaction may have explained the loss of forest organisms and the
persistence of simple understorey in old plantations, despite 30 years of growth
and more than six years since disturbance by fire or harvesting.
Early maturity (spar) plantations differed from young and old plantations
in having similarly simple understorey structure, but closed canopies, producing
a cool thermal environment with low light penetration. Although spar plantations
are a short-lived stage in the plantation cycle before the canopy is opened by
subsequent harvesting, they could represent a valuable habitat resource for
forest fauna that prefer cool thermal environments but are tolerant of simple
structure. From a management perspective if this stage of plantation is
promoted within the landscape mosaic at forest-plantation boundaries, it may
provide forest species with additional habitat, and buffer forest from the
microclimatic extremes experienced in young and old plantations.
Despite large thermal and structural differences herpetofauna, birds and
mammals were equally speciose in old growth and logged native forests and
young and old plantations. Assemblage structure differed significantly, and
plantations were dominated by generalists and woodland species. Small ground
xiii
mammals were less abundant in young plantations. Thus while afforested
plantations provided habitat where habitat was previously absent, in both young
and old plantations the ecological resilience of communities may have been
compromised by lower species richness. From a landscape perspective
plantations offered habitat to declining woodland birds, and increased the
functional range of woodland species in agricultural environments.
Using small lizards as a model and conducting feeding and behavioral
choice experiments, this thesis demonstrated that the thermal environment in
young plantations was physiologically limiting to forest species. While
temperatures optimal for digestive efficiency could be achieved, they required
the species using this forest type to exhibit flexibility in both activity time and
substrate choice. The forest species that did not possess this flexibility could not
use young plantations. Those species that had the physiological capacity to
exploit plantations were behaviourally constrained, and would only be likely to
use young plantations if targeted understorey enrichment were provided.
The low abundance of insectivorous ground fauna identified from young
plantations in this research was not driven by a lack of invertebrate prey, which
was equally available in young and old plantations and native forests. Low
mammal abundance was likely to have been related to the simplicity of the
plantation environment rather than a decline in forest matrix quality associated
with cattle grazing. However for herpetofauna, grazing may have increased the
permeability of the forest matrix, with a resultant influx of thermophilic species
into plantations.
xiv
Collectively the results of this research stress that: 1) young and old
native plantations can support faunal assemblages as diverse as those in native
forests, but for small mammals in particular, abundance in plantations is low; 2)
cooler spar plantations have the potential to act as thermal stepping stone which
may promote incursions of forest species into plantation mosaics; 3) young and
old plantations can support an invertebrate prey base as diverse as that in
adjacent native forests, with positive benefits on the species richness of
insectivores; and 4) the role of grazing in the forest matrix requires further
investigation in order to clarify its role in influencing species exchange between
plantations and forests.
xv
Acknowledgements
So where does one begin…….at the beginning I guess. Thanks go to all those
people that helped this piece of work come together. Peter Levitske (SFNSW
Wauchope) provided great initial info. Andrew Marshall (NPWS Port Macquarie)
provided an Anabat . Mike Thompson at USYD generously lent me his data loggers.
Brad Law from SFNSW Pennant Hills trustingly shared his data.
Never will I forget the people who came and dug holes just for the fun of it
including: Adrian Ferguson, Ittai Renan (who loved phasmids with me), Stephen and
Tarn (who dug many many holes), and Johann who laughed in the face of bats one
very, very hot Christmas week.
My supervisors deserve much thanks for support and dedication. Kris French
was unendingly patient, and made sure I was not lost in the forests literally and
figuratively; Bill Buttemer gave comments to improve my science. Frank Lemckert just
was.
John and Janette Cook get a very special mention for lending me their luxurious
shed and a site for field enclosures. Also for sharing their lives with me for what seems
like only a minute, but was actually nearly 4 years. May they be blessed by the many
gods for being so open-hearted, for sharing stories, letting me shovel woodchip, camp
with their redheads down the back and jump in the dam one lovely New Year. My
thanks endure.
Elsewise and northwards there were all the rest of my people. Simon gifted
invaluable science talk, encouragement and laboured through drafts like a man
possessed. Pod gave statistics and smiles; Sam and Leonie reminded me of sunshine.
Kathleen talked turtles and fish from afar and Fiona kept me dreaming of snow. Of my
southern folk I must thank my lab, in particular Tanya who remains ever lovely and
xvi
whose professional attitude was inspiring. Also thanks go to Craig who was fun.
Gerhard talked good science throughout. Mats gave me hatchlings to love. I hope you
feel me on this one people. I am beyond grateful for all your support.
My family deserves special mention. Mum bent fence poles for days at the
beginning of this project, sent money and help when it was needed, scrubbed traps
multiple times, built field enclosures whilst dodging snakes, babysat and cheered. If I
can imitate one quarter of the strength, beauty and generousness of this woman then I’ll
be doing well. Stephen painted my truck and drove north to rescue mountains of gear at
the end and did everything else in between. Tarn shared the forest with me, talked
muesli, and believed. James gave moments of joy, and missed me. You’ve all heard my
thanks, but hear it again now. You’re incomparable. Along with these people I must
mention the Frenchman. His patience has been enduring and his love boundless.
Bunya made fencing fun and dreamed on my feet while I wrote. My exquisite daughters
have given me their patience and a heart overflowing. I am so blessed to share them.
Finally I want to thank this beauteous Earth. She provided me with the great joy
I took from this project, and lent me her people for a moment. I am deeply honoured.
Now I just have to work out how to pay that one back.
Much peace.
xvii
Chapter 1: Introduction
Chapter 1
The conservation value of native tree plantations
for wildlife
Introduction
Recognition of 2011 as The International Year of The Forests
highlights the current interest in the world’s forests, with growing awareness
of their vital role in maintaining a stable global climate. Native forests
throughout the world are being converted to other land uses at a rate of
approximately 16 million hectares a year (FAO 2010), in conjunction with a
rapid decline in biodiversity (Perfecto & Vandenmeer 2010). One widely
adopted international initiative to halt global forest decline involves
establishing tree plantations to provide a source of wood products to the
industrial systems which use more than ninety percent of the timber
harvested from forests (Kanowski 1997). This approach is working and
although global forest loss is not offset by the current rates of afforestation, it
is mitigated, reducing the total per year loss to 5.2 million hectares a year
(FAO 2010).
Plantations currently represent 6.6% of the world’s forests (FAO 2011),
and estimates of global expansion project that this will increase to between
10 and 20% in the next 15 years (Sample 2003). While industrial plantations
have conservation significance because they reduce timber harvesting in
native forests (FAO 2011), international bodies such as the Forest
Stewardship Council recognize that plantations have inherent biodiversity
conservation value that should be promoted, especially where plantations
1
Chapter 1: Introduction
dominate the local landscape (Mercer & Underwood 2002). Promoting
plantations as a management practice, associated with sustainable forest
management, concerns some conservationists (Spellerberg 1997, Clapp
2001), primarily because there is little agreement about how plantations do
benefit the environment (Bremer & Farley 2010). While timber plantations
can play a significant role in conserving biodiversity by reducing timber
harvesting in native forests (Sedjo & Botkin 1997, Brockerhoff et al. 2008),
their value for flora and fauna as new habitat on afforested lands relies
strongly on the impact establishment has on the landscape in which they are
embedded (Bremer & Farley 2010) as well as the context of the plantation in
the landscape mosaic (Felton et al. 2010). How well plantations can
compensate for natural forest loss by acting as natural habitats is directly
affected by the similarity between native forests and plantations in tree
species composition (Brockerhoff et al. 2008, Bremer & Farley 2010), the
structural and physical environment this engenders, and the management
regime applied (Brockerhoff et al. 2012).
How well plantations support biodiversity is not always clear, often
because the term ‘plantation’ can refer to a large range of stand types and
tree species mixtures (Hartley 2002), which are often exposed to very
different management regimes depending on the end use of the plantation,
establishment goals, ownership, management practice and wood product
end use. For the purpose of this paper a plantation is defined following the
global plantation forests thematic study (FAO 2006) which identifies
productive plantations as “forests of introduced and in some cases native
species, established through planting or seeding mainly for the production of
2
Chapter 1: Introduction
wood products”. Typically large-scale tree plantations are planted and
managed as monocultures to homogenise the quality of fibre inputs for pulp
production (ABARE 1999a) and to ease mechanised harvesting. Unlike
natural forests, managed monocultures lack structural complexity; instead
being characterised by evenly aged and distributed stands of trees (Evans
1997, Turnbull 1999) and open and simple canopies. Specifically, they lack
the horizontal and vertical structural complexity associated with multilayered
canopies, logs and snags and uneven tree sizes (McCullough 1999). The
understorey in monoculture plantations is typically either missing or highly
simplified, however, without ongoing management, plantation understoreys
can develop high vegetation diversity depending upon levels of crown closure
and propagule availability (Bowen et al. 2007, Archibald et al. 2010). Thus,
how different plantations are from forests can vary greatly with the type of
plantation examined.
The value of plantations for fauna has been reviewed several times by
Christian et al. (1998), Moore and Allen (1999), Lindenmayer and Hobbs,
(2004), Kanowski et al. (2005), Carnus et al. (2006), Gardner et al. (2007a),
Stephens and Wagner (2007), Brockerhoff et al. (2008), Munro et al. (2009),
Hartmann et al., Felton et al. and Nájera and Simonetti (2010). These
reviews find no general consensus that plantations either promote or
decrease faunal diversity. Such a lack of consensus is unsurprising given
that vegetation species, climate, site conditions, management, scale, age
and species composition can all affect faunal responses to plantations
(Hartley 2002, Lindenmayer & Hobbs 2004, Gardner et al. 2007b), and these
reviews combine results across plantation ages and differing landscape
3
Chapter 1: Introduction
contexts. Further, the lack of consensus between reviews may also be
compounded by a failure to differentiate different types of plantations, which
occurs in 80% of past reviews that assess the suitability of plantations as
faunal habitat (e.g. exotic and native -Felton et al. 2010; timber plantations
and other tree crops such as rubber -Náejera & Simonetti 2009). Pooling of
plantation types in research can obscure particular types of plantations that
may better represent faunal habitat. The overarching conclusion of past
reviews is that plantations support lower total species diversity than forests,
but that particular groups of fauna may be abundant. Individual studies have
identified that plantation faunal assemblages are often dominated by
generalists, edge specialists and exotics (Bengtsson et al. 2000, Davis et al.
2000, Boorsboom et al. 2002, Gardner et al. 2007b). Whether different sorts
of plantations can support a diverse array of fauna and by extension, and
how well plantation faunal assemblages provide ecosystem services (e.g.
pest control, pollination) is unclear (Carnus et al. 2006). Without this sort of
knowledge, advocating that plantations generally have conservation value for
fauna or that they can extend faunal habitat (Paquet & Messier 2010, FAO
2011), must be qualified to certain faunal groups.
Plantations of native tree species may have the potential to better
represent faunal habitat than exotic tree plantations (e.g. Farwig et al. 2008,
Bremer & Farley 2010) because they provide familiar microenvironments,
food and habitat resources for vertebrate and invertebrate fauna (Hartley,
2002). Understanding the value of native plantations is rapidly becoming
important as native species planting rates increased globally by 49%
between 2005 and 2010, and in Australasia the establishment rate of native
4
Chapter 1: Introduction
plantations currently equals those of exotic species (FAO, 2010). In the last
ten years a large body of literature examining the value of native plantations
for biodiversity has emerged. This literature primarily focuses on plantations
generated for protective functions, whilst research focussing on timber
production plantations remains a narrow field, even though industrial timber
plantations comprise >60% new plantations established globally (FAO 2010).
This chapter examines the conservation value of managed timber
plantations of native tree species for vertebrate fauna. To assess whether
there is a literary consensus that native plantations can act as reservoirs of
for diverse faunal assemblages, we used meta-analysis techniques to
determine whether stand-level faunal species richness and abundance was
lower in native timber plantations than native forests, and how consistent this
effect was across animal taxa. The effect of simplified understorey complexity
on species richness and abundance was also examined, as understorey
complexity has previously been recognised as a major determinant of
diversity for all animal groups in plantations (birds- Nájera & Simonetti 2010,
mammals - Ecke et al. 2002, reptiles – Brown & Nelson 1993, invertebrates –
Humphrey et al. 1999). We hypothesized that the richness and abundance of
ground mammals, reptiles, birds and invertebrates would decline from forests
to native plantations with complex understories, and that plantations with
simple understories would support the least rich and abundant faunal
assemblages.
5
Chapter 1: Introduction
Methods
Data extraction
We searched the electronic databases ISI Web of Science, Google
and Google Scholar for literature examining faunal species diversity with
plantations. Additional information was obtained from public and private
reports and by back referencing published studies on faunal use of
plantations (Moore & Allen 1999, Hartley 2002, Lindenmayer & Hobbs 2004,
Carnus et al. 2006, Stephens & Wagner 2007, Brockerhoff et al. 2008,
Nájera & Simonetti 2009).
While literature addressing physio-chemical properties of native
plantations and their role in reafforestation and agroforesty (particularly palm
oil, coffee and cacao) was common, there were few studies comparing
managed native plantations with forests of the same or closely-related
species. 224 studies investigated native monoculture plantations but only 35
examined fauna, and of these only 21 presented quantitative data on species
richness and/or abundance. Most studies were excluded from analysis after
failing to adequately define either the age of the plantation under
investigation, the condition of the understorey or the level of management
experienced in the plantation. 55% of cases focussed on birds, 35%
focussed on invertebrates, and 15% on reptiles or mammals (Table 1). The
spread of research was adequate and originated from temperate and tropical
South America, the Mediterranean, the Boreal North, temperate and tropical
Oceania, Central Africa and North America. Australian research contributed
52% of all records. Qualifiers were necessary to avoid confounding sources
6
Chapter 1: Introduction
Table 1. Studies examined in this meta-analysis comparing forests and native plantations.
Publication
Farwig et al.2008
Klomp & Grabham 2002
Loyn et al. 2007
Loyn et al. 2009
Proença et al. 2010
Repenning & Labisky 1985
Volpato et al. 2010
Zurita et al. 2006
Hsu et al. 2010
Boorsboom et al. 2002
Kavanagh et al. 2005
Fonseca et al. 2009
Bentley et al. 2000
Kanowski et al. 2005
Cunningham et al. 2005
Schnell et al. 2003
Taboada et al. 2008
Tattersfield et al. 2001
Yu et al. 2008
Grimbacher et al. 2007
Gries et al. 2012
Dominant tree species
Maesopsis eminii
Eucalyptus spp.
Eucalyptus globulus
Eucalyptus globulus
Quercus spp.
Plantation age
old
young
young
young
old
Understorey complexity
complex
simple
simple
simple
simple
Taxon investigated
birds
birds
birds
birds
birds
Country
Africa
Australia
Australia
Australia
Portugal
Pinus palustris
Arucaria angustifolia
Araucaria angustifolia
Eucalyptus pilularis
Eucalyptus spp.
Eucalyptus spp.
Arucaria angustifolia
Araucaria cunninghamii
Araucaria cunninghamii
Eucalyptus globulus
Eucalyptus punctata
Pinus sylvestris
Maesopsis eminii
Larix mastersian
Araucaria cunninghamii
Eremanthus erythropappus
old
old
old
young
old, young
old, young
old
old
young
young
young
old, young
old
old
old, young
young
complex
complex
complex
simple
complex
simple, complex
complex
complex
simple
simple
simple
complex
complex
simple
simple, complex
simple
birds
birds
birds
birds
birds, mammals, reptiles
birds, mammals, reptiles
birds, mammals, invertebrates
mammals
reptiles
invertebrates
invertebrates
invertebrates
invertebrates
invertebrates
invertebrates
invertebrates
North America
South America
South America
Australia
Australia
Australia
South America
Australia
Australia
Australia
Australia
Spain
Africa
China
Australia
South America
cases
2
1
1
1
2
3
1
1
1
8
18
3
1
2
1
1
3
1
1
4
2
7
Chapter 1: Introduction
of variability when comparing forests and plantations. Research was included in
this meta-analysis if it met the following criteria:
Plantations:
-
Plantations of trees native to a landscape but planted where they were not
endemic, were deemed native. All non-timber plantation commodities were
excluded.
-
This meta-analysis did not include studies in which clear-cutting and
subsequent natural regrowth resulted in even aged forests. Plantations were
defined as stands of trees specifically planted for timber production.
-
Only plantations with a documented management history were included.
-
Understorey was classified as structurally complex or simple as reported by
the research author/s. Where understorey complexity was not specifically
reported but vertical foliage density was quantified, understorey was scored
as simple or complex based upon results of analysis by the individual author
(e.g. Farwig et al. 2008).
-
Plantation age was categorized as young (2-10 years old) or old (+20 years
old), as it is recognized as strongly affecting species diversity in plantations
(Hartley 2002), primarily through changes in canopy cover and understorey
complexity.
Forests:
To avoid including research biased by island effects (Gascon et al. 1999) forests
had to meet the following criteria of being:
-
More than ten hectares in size;
8
Chapter 1: Introduction
-
Unlogged for a period of at least 20 years prior to sampling;
-
Situated within 15 kilometers of plantations.
Fauna:
-
Exotic species were excluded from species lists and only species recorded
during formal surveys were included.
-
Mammal data were restricted to small ground mammals and invertebrate
data excluded soil dwelling and volant species, as records for large
mammals, soil fauna and volant species of all taxa were inconsistently
reported between studies.
Each research article was scored once per plantation-forest comparison for
species richness and/or abundance of invertebrates, mammals, birds or reptiles.
Studies that reported several sets of results were scored more than once if the
data presented were obtained from independent experiments, or where multiple
ages of plantation fitting the age criterion above were investigated. This created
a correlated data structure for some studies.
Data analysis
Data analysis involved compiling estimates of species
richness/abundance calculated from species lists when not presented directly.
The corresponding estimates of standard deviation were back-calculated from
sample size and estimates of standard error, using standard mathematical
techniques. These were measured from graphs if not directly presented. The
data set available for this meta-analysis faced two challenges; it was small and
the data structure was correlated where multiple responses to a single control
9
Chapter 1: Introduction
were recorded. Whilst averaging the responses of the correlated data or
randomly choosing a single response from a correlated set is a solution to
correlation (Lipsey & Wilson 2001), it necessarily reduces the power of an
analysis (Marín-Martínez & Sánchez-Meca 1999, Hochachka et al. 2007). In this
meta-analysis such averaging would have also confounded plantation age
categories. Instead, effect sizes which measure the magnitude of effect present
in each study were generated by calculating Hedge’s g, a metric commonly used
in ecological studies (e.g. Osenberg et al. 1997; Mason et al. 2009).
Hedge’s g calculates standardized mean differences around treatment
means, by dividing the difference between the mean of the treatment and control
groups by the pooled standard deviation of both groups (Hedges & Olkin 1985),
and uses a generalized least squares framework which can be modified to
address violations due to non-independence of data. However it is known to be
biased towards Type I errors at small sample sizes (Hedges & Olkin 1985).
Whilst Response Ratio (RR) is a metric known to have better statistical
properties for small data sets, Lajeunesse and Forbes (2003) identified that
whilst RR generated fewer Type I errors (detecting an effect when none is
actually present) than Hedge’s g when there were less than 15 studies, its
precision did not improve with sample size above ten studies. Whilst a multiple
lines of response approach to analyzing data, using both RR and Hedge’s g has
been adopted by other researchers with small data sets (see Van Zandt &
Mopper 1998, Kopper et al. 2009) this method can lend itself to selective
interpretation of results. For this meta-analysis, Hedge’s g was generated to
10
Chapter 1: Introduction
measure effect size, with the application of correction factors for small sample
size and for correlation. Correction for correlation multiplying g by the shrunken
correlation coefficient (rs) (Campbell 1980) for each correlated study. Correction
by rs weighted the strength of the relationship between means by the number of
variables and the number of data points (Kufs 2011), and so reduced the withinstudy variance, increasing the precision of the estimate of effect size (Hedges &
Olkin 1985). Rs were calculated as:
s
r =
1−�1−𝑟 2 �(𝑛−1)
𝑛−2
However, for 50% of the correlated cases used in this meta-analysis, and for
many published studies, data allowing calculation of correlations are often
unavailable (Wampold et al. 1997). Where shrunken correlation could not be
calculated a correlation of 0.5 was chosen to aggregate the effect sizes. This
was assumed to be a reasonable estimate of correlation, as where rs could be
calculated from the studies included in this meta-analysis, values fell between
0.49 and 0.57.
Subsequently, Hedge’s g was derived from:
g=
and from
g=
𝑋�𝑇 − 𝑋�𝐶
Sp
𝐽
𝑋�𝑇 − 𝑋�𝐶
Sp∗�√1−𝑟 𝑠 �
for uncorrelated data
𝐽
for correlated data
with
11
Chapter 1: Introduction
Sp = �
(𝑛1 −1)𝑠𝑇2 + (𝑛2 −1)𝑠𝐶2
𝑛1 + 𝑛2 − 2
and
J=1
−
3
4(𝑛1 + 𝑛2 −2)−1
�𝑇 was the mean plantation species richness or abundance, 𝑋�𝐶 was the
where 𝑋
mean forest species richness or abundance, Sp was the pooled standard
deviation, J was a correction factor for small sample bias, 𝑛1 ,𝑛2 , 𝑠1 and 𝑠2 were
the forest and plantation sample sizes and standard deviations respectively. The
degree of deviation from zero represented the strength of an effect, and
negative values of effect size reflected an increase in species
richness/abundance in forests. Effect size distributions were normalized before
analysis by removing the study by Gries et al. (2012) and two cases from the
study by Grimbacher et al. (2007), which were identified in
normal quantile plots as highly non-normal.
After examination of the data, analyses of plantation age were
abandoned for all analyses except bird richness, as the data available for old
plantations with simple understory was too small to allow meaningful statistical
comparisons. All other analyses were pooled across plantation ages. Randomeffects models were used to identify any differences in species richness or
abundance between plantations and forests for all fauna. Random effects
models identify heterogeneity in effect sizes by estimating the mean of a
distribution of true effect sizes, and so account for within-study heterogeneity in
the data originating from moderator variables (understorey complexity) and
12
Chapter 1: Introduction
between-study heterogeneity stemming from differences in methodology and
design (Borenstein et al. 2009). For mammals the lack of heterogeneity in the
abundance data required the use of a fixed effects model, as no data were
available for mammals in plantations with simple understories.
Confidence intervals around corrected g estimates used to compare the
effect of understorey complexity on richness, were calculated using resampling
techniques with 20 000 iterations. Overlap between confidence intervals can be
as informative as p-values themselves in meta-analysis (see Durlak 2009), and
non-parametric estimates are less biased by sample size (Gliner et al. 2003). All
analyses were carried out using the MetaWin program, version 2.1 (Rosenberg
et al. 1997). Effect sizes were considered significant at the p < 0.05 level, and
mean effects were rated as small (0.2). medium, (0.5) or large (≥0.8) following
Cohen’s rule-of-thumb (1988). In forest plots generated to depict the spread of
effect sizes, a shift towards to the left of zero was interpreted as a stronger
effect in forests, whilst a shift towards the right of zero indicated larger effect
sizes in plantations (see Rosenberg et al. 1997).
Results
Hypothesis: plantations with simple understories support less rich or abundant
faunal assemblages than plantations with complex understories or forests.
In opposition to the hypothesis posited, native plantations and forests
supported similarly rich faunal communities (Table 2). Negative effect sizes
indicated a consistent non-significant trend for species richness to be higher in
13
Chapter 1: Introduction
forests, as indicated by the skew of mean effect sizes to the left of Figure 1a.
Whilst understorey condition did not affect overall significance it did moderate
species richness. When understories were complex bird, mammal and reptile
richness increased. Bird richness was equivalent between forests and
plantations with complex understories (confidence intervals bracket zero), and
between young and old plantations, but became more variable in plantations
with simple understories (Table 2). These trends were strong (mean effect sizes >
0.701) and consistent across both young and old plantations. As for birds,
reptile richness was most similar between plantations with complex understories
and forests as is reflected by the confidence intervals around the mean effect
size approaching zero (Table 2), and the clumped distribution of mean effects in
Figure 1a. This result was considered to be moderately strong (mean effect size
= -0.594). For invertebrates an effect of either plantation understorey
development or overall forest type was not detectable as high variability
between studies obscured trends (Fig. 1). A strong mean effect (-0.830), was
offset by a high mean study variance ratio (2.859) suggesting the response of
invertebrate richness to changes in forest structure was affected by unmeasured
variables. For mammals, whilst Figure 1a shows a spilt between simple and
complex plantations and a trend towards complex plantations supporting higher
richness, a weak effect size (E+ = -0.31, mean variance ratio = 1.594)
suggested that accurate conclusions for this group required a greater sample
size.
14
Chapter 1: Introduction
In contrast to species diversity, the abundance of reptiles, invertebrates
and birds differed significantly between forests and plantations. Plantation
understorey complexity influenced abundance in complex ways for each animal
taxon. For birds, invertebrates and mammals when plantation understories were
complex species richness was equivalent in forests and plantations (confidence
intervals for mean effect sizes bracketed zero, Table 2). Where plantations had
simple understories bird abundance was significantly (p < 0.000) and
consistently (mean study variance ratio = 0.833) reduced. Reptiles were
similarly abundant in forests and plantations with simple understories
(confidence intervals bracket zero), but abundance was highest in plantations
with complex understories (Table 2, mean effect size = -1.075, Fig 1b). As for
richness, invertebrate abundance showed the highest variability in response to
forest change of the four taxa examined in this meta-analysis (mean study
variance ratio = 1.067). Invertebrates were the only group in which abundance
was strongly negatively associated with complex understorey (mean effect size
= 2.168, Table 2).
15
Chapter 1: Introduction
Table 2. Q tests for meta-analyses testing for differences in effect sizes (E+) with
changes in species richness and abundance between forests and plantations. Analyses
are repeated for birds, mammals, invertebrates and reptiles. Degrees of freedom = 1 for
all random analyses and 8 for the fixed analysis of mammal abundance. n = the number
of comparisons between plantations with simple (s) and complex (c) understories. OP =
old plantations, YP = young plantations.
Understorey
Faunal group
condition
Species richness
Birds OP
c
s
YP
c
s
Mammals
c
s
Invertebrates
c
s
Reptiles
c
s
Abundance
Birds
Mammals
Invertebrates
Reptiles
c
s
c
c
s
c
s
n
Q
p
E+
Mean E+
10
5
3
5
6
4
5
5
6
8
3.278
0.070
-0.728
0.256
0.613
0.097
0.755
0.112
0.738
0.114
0.736
-0.310
-1.397
-0.674
-1.079
-0.223
-0.388
-0.573
-1.053
-0.540
-0.637
11.640
<0.000
7.870
4.257
0.446
0.039
5.356
0.021
11
5
8
3
2
8
2
0.181
-1.347
-0.119
2.168
-0.127
-1.281
-0.911
-0.311
-0.830
-0.594
-0.226
-0.089
0.562
-1.075
Bootstrap CI
lower
upper
-0.879
-2.780
-2.157
-1.786
-0.845
-0.867
-2.157
-4.025
-0.901
-0.852
-
0.101
-0.419
0.856
-0.556
-0.786
0.099
0.857
1.123
-0.071
-0.328
-0.249
-2.314
-0.938
-1.014
1.259
-1.708
-0.390
-
0.558
-0.660
0.794
0.783
4.492
-0.901
0.134
Whilst abundance in was equivalent in forest and plantations with complex
understories, it increased significantly in plantations with simple understories
(mean effect size = 2.168, Table 2, Fig. 1b). Similarly, mammals were equally
abundant in old plantations with complex understories and forests (Table 2, Fig
1b), however, this result was considered weak (mean effect size = -0.089), and
the distribution of effect sizes was bimodal (Fig. 1b).
16
Chapter 1: Introduction
Fig.1. Forest plots of standardized differences in (a) species richness and (b)
abundance between forests and native plantations based on 20 independent studies.
The vertical line represents no difference. Error bars show means and associated 95%
confidence intervals. Points falling to the left of the zero line indicate a stronger effect in
forests, whilst the points falling to the right indicate a stronger effect in plantations.
17
Chapter 1: Introduction
Discussion
Managed native timber plantations can support an array of fauna equally
as species rich and abundant as native forests, and that this result was
consistent across faunal groups. Understorey complexity was not significantly
associated with increased species richness in plantations, but strongly
moderated faunal abundance. When plantation understories were complex bird
and mammal abundances were high and equivalent between forests and
plantations. However reptiles and invertebrates were more abundant in
plantations than forests. Plantation age did not affect bird richness. Collectively
these results provides support for the idea that native plantations can better
benefit fauna than exotic plantations (Hartley 2002), and highlight that directed
meta-analyses can clarify states of knowledge when research findings from
multiple studies are inconsistent. The equivalence of results from this metaanalysis and earlier meta-analyses that specifically compare native forests with
native plantations (Stephens & Wagner 2007), suggest that native plantation
monocultures with simple understories situated in close proximity to forests, can
play a role in conserving faunal diversity in forests at a local scales.
Native plantations support diverse faunal assemblages
This meta-analysis identified a consistent trend in the literature for
managed native plantations to support a forest-like richness of birds, mammals,
reptiles and invertebrates at the stand-level. This contradicts those of individual
research (Hobbs et al. 2002, Boorsboom et al. 2002), which identify less diverse
native plantation faunal assemblages compared to those in forests. Brown et al.
18
Chapter 1: Introduction
(2001b) suggest that species diversity can be maintained within narrow limits
provided resources are constantly available and systems are open to migration,
even though species composition may vary greatly. Further, Pardini et al. (2009)
identify that low contrast landscape matrices better support high faunal richness
and abundance. In this meta-analysis native plantations of endemic tree species
necessarily provided low-contrast to adjacent forested environments, and
qualifiers for the inclusion of data specified that forests were of good quality and
that plantations were within close proximity to forests in the landscape. Hence
the consistently high species richness in plantations identified in this metaanalysis may result from an enhanced potential of forests to supply recruits to
plantations.
Age has been recognised as an important determinant of faunal diversity
in plantations, primarily because it is often equated with successional
development in both unmanaged (Bremer & Farley 2010) and managed
plantations (Cummings & Reid 2008). In opposition to reviews pooling exotic
and native tree species (Nájera & Simonetti 2009) and individual studies
(Boorsboom et al. 2002), this meta-analysis identified that bird richness was
insensitive to plantation age, suggesting that young plantations in proximity to
native forests either undergo rapid species replacement, or experience highly
dynamic use by birds. It is probable that managed young plantations can attract
a diverse array of bird species because native tree species provide familiar
foraging substrates and food resources (Hartley 2002), and abundant
invertebrate populations facilitate incursions into young plantations, despite low
19
Chapter 1: Introduction
structural diversity. It is important to qualify that the data available for this
analysis of plantation age included Australian research only. To more accurately
quantify the role of young native plantations in supporting fauna generally, a
more comprehensive global assessment needs to be undertaken as this data
arises. It is probable that both understorey development and resource
availability will vary considerably in young plantations depending on the
productivity of environment in which they are established, and so influence both
bird diversity and overall faunal use of young plantations.
Understorey complexity moderates faunal abundance
Understorey complexity has been consistently identified as a strong
predictor of animal diversity, and in both native and non-native plantations.
Previous reviews have associated simply structured understories in native
plantations with reduced faunal diversity and abundance (Moore & Allen 1999,
Lindenmayer &Hobbs 2004, Carnus et al. 2006, Nájera & Simonetti 2010,
Brockerhoff et al. 2012). The results from this meta-analysis agree with former
reviews. In contrast to previous reviews however, reptiles were as abundant in
these plantations as they were in forests, and invertebrates (predominantly
beetles) were far more abundant. It is likely that for reptiles and ground
invertebrates young native plantations offer increased thermal opportunities and
abundant food resources which support high abundance. Whilst there was no
data available allowing a meta-analysis of small mammal response to young
plantations, individual authors identify lower diversity in young native plantations
than in forests (e.g. Boorsboom et al. 2002, Ramírez & Simonetti 2011), and
20
Chapter 1: Introduction
shifts in assemblage composition towards generalist species (e.g. Mitchell et al.
1997), as mammals are strongly dependant on habitat complexity (Holland &
Bennett 2007).
The variation between the responses of animal taxa is driven by the need
for different taxa to exploit habitat differently and is common in many cross-taxa
comparisons (Lawton et al. 1998, Schulze et al. 2004, Felton et al. 2010). Whilst
the results of this meta-analysis highlight the importance of complex
understories for supporting high faunal abundance in plantations, they also
identify that ground fauna respond to changes in plantation understory condition
very differently to more mobile animals like birds. As Felton et al. (2010) suggest,
the need for a case-specific assessment may be necessary to both reliably
predict the responses of ground fauna to simplifying plantation understories, and
to understand the persistence of diverse and abundant faunal assemblages in
plantations over time.
Plantations as habitat
Whilst an assessment of the identity of faunal communities using native
plantations was not a focus of this meta-analysis, it is important to qualify that
equivalent species diversity does not equate to similar species composition.
Whilst this meta-analysis identified diverse faunal communities using
plantations, it is likely that these communities are not dominated by forest fauna.
The individual studies used to generate this meta-analysis repeatedly identified
plantation faunal assemblages as lacking in forest specialists. Many forest
species are particularly sensitive to forest naturalness (e.g. Farwig et al. 2008,
21
Chapter 1: Introduction
Proença et al. 2010), and the persistence of forest species in plantations, whilst
often related to understory condition (Aubin et al. 2008), is likely to be driven by
a complex array of factors. Further, the way in which fauna are sampled and
subsequently grouped strongly influences the outcome of results in metaanalyses (Felton et al. 2010). For example, in this meta-analysis invertebrate
samples were heavily biased towards beetles, which respond strongly to
successional stages of vegetation (Pawson et al. 2009). Thus high invertebrate
abundance in plantations with simple understories reflects that plantations are
good habitat for beetles, but not necessarily other invertebrates.
Acknowledgement of assemblage identity is particularly important when
assessing the value of native plantations as faunal habitat. Without a focussed
assessment of the identity of fauna using native plantations, we can conclude
that whilst native plantations in forested environments can support diverse and
abundant faunal assemblages, these assemblages may be comprised of
generalist, edge specialist and exotic animals (Bengtsson et al. 2000, Davis et al.
2000, Boorsboom et al. 2002) rather than forest specialists.
Stephens and Wagner (2007) argue that the true conservation value of a
forest is determined by comparing it to the land use it replaces. In this case the
literature examined often failed to identify any pre-plantation land use, and thus
this meta-analysis necessarily became a comparison of plantations with forests.
The results of this meta-analysis identify native plantations as a feasible means
to augment and support native forest diversity, if not the diversity of forest
specialist species. Whilst we acknowledge the small sample size of the overall
22
Chapter 1: Introduction
data set, we identify that the very strong effect of understorey complexity on
faunal abundance in plantations identified in this meta-analysis, suggests
developing or retaining a complex understorey in plantations should be
recognised as a key management concern if maintaining diverse faunal
communities is a goal. Further investigation of the role of ecological
management (e.g. Fischer et al. 2006, Hsu et al. 2010) may provide guides to
developing high faunal diversity in managed native plantations, without
compromising timber production.
Continuing work in context
This thesis is an original body of work that increases knowledge of
monoculture hardwood plantation habitat use by fauna in Australia. This metaanalysis has identified that despite their growing presence in the global
plantation estate very little research is focussed on faunal diversity in managed
native tree plantations. Particularly, our knowledge of young plantations as
habitat is often context specific and generally poor, particularly for ground fauna.
In this thesis I extend knowledge of young plantations as habitat, and
specifically focus on ground fauna. I address the ecological context of faunal
assembly in native plantations in comparison to native forests, and assesses
whether plantations are physiologically limiting for ectotherms. Specifically I
compare faunal diversity between industrial monoculture Eucalyptus plantations
(Blackbutt - Eucalyptus pilularis) and adjacent native forests, and investigate
some of the potential reasons for the associations identified between vegetation
23
Chapter 1: Introduction
structure and faunal habitat use by exploring the relationship between shifts in
habitat structure and faunal habitat use. I further explore some of the
mechanisms that generate the observed relationships using thermal physiology
for reptiles, and landscape context and prey availability for ground fauna. My
approach to understanding faunal use of modified habitats such as managed
forests and plantations incorporates broad sampling across all animal groups
including birds, small mammals, herpetofauna and invertebrates, an approach
that is still relatively new for plantations generally. This is also the first Australian
study that has comprehensively compared the thermal environments available to
wildlife in plantations and native forests. I aim specifically to:
1. identify differences in vegetation structure, and thermal environment (light,
air temperature) between plantations and native forests and within
plantations of different ages (Chapter 2)
2. examine how these environmental differences alter patterns of habitat
use by multiple taxa of vertebrate fauna (Chapter 3)
3. determine whether there are differences in food resource availability for
insectivorous small mammals and herpetofauna between plantations and
forests (Chapter 4)
4. determine whether the landscape context of plantations influences habitat
use by small mammals and herpetofauna (Chapter 5)
5. experimentally examine how the dependence on specific structural or
thermal attributes in an environment influence habitat use by one faunal
24
Chapter 1: Introduction
group (scincid lizards), and to determine the physiological basis of habitat
preference in this group (Chapter 6)
This thesis is presented as a series of chapters that address the aims above.
Due to use of the same sites and capture methodologies for more than one aim
and the need to fully explain methodologies in each paper, the introductions and
methods in some chapters may be extensive.
25
Chapter 2: Plantation microclimate diversity
Chapter 2
Thermal and structural characteristics in native
plantations: implications for microclimate diversity
Introduction
Available microclimates are a valuable, yet often poorly quantified
resource for biotic communities. They control plant distributions
(Stoutjesdijk& Barkman 1992), and are a recognised habitat selection cue for
ectothermic (invertebrates – Retana & Cerdà 2000; Pereboom & Beismeijer,
2003; Ouedraogo, 2004; amphibians - Halverson et al., 2003; fish - Wherly et
al., 2003; reptiles – Huey & Slatkin, 1976; Hertz et al., 1994; Webb & Shine,
1998; Sartorius et al., 1999), and endothermic animals (small mammalsLagos et al. 1995, Pienke & Brown 2003, Sedgeley 2001, Chruszcz &
Barclay, 2002; birds - Wolf & Walsberg, 1996). Microclimates are produced
by the interaction between vegetation structure, heat and light. Canopy
openings increase the diversity of microclimates experienced by organisms
at the forest floor (Van Calster et al. 2008) by allowing greater penetration of
solar radiation (Hanley 2005, Weng et al. 2007), so increasing light, air and
surface temperatures, (Clinton 2003, Martius et al. 2004, Rambo & North
2008) and modifying soil temperatures and humidity (Kanowski et al., 1992;
Palik & Engstrom, 1999). Secondarily both leaf shape dictated by tree
species (Yirdaw & Luukkanen 2004, Strobl et al. 2011) and sub-canopy
vegetation complexity influence light attenuation and heat penetration to the
forest floor (MessierPorté et al. 2004), and so the distribution of
microclimates available for organisms to exploit.
26
Chapter 2: Plantation microclimate diversity
Industrial tree plantations are a forest type exposed to high levels of
management-induced canopy and understorey disturbance. In native
eucalypt plantations management practices including slashing, grazing and
thinning produce simpler and more open tree canopies and sub-canopies
than forests and typically a less structurally complex understorey (Kanowski
et al. 2003, Brockerhoff et al. 2008). As a consequence plantation
understories are often exposed to higher levels of light, solar radiation
(Florence 2004) and air mixing (MacDonald & Thompson 2003, Laurance
2004, Wright et al. 2010) than forests. In exotic plantations these
management practises result in increased litter, air and soil temperatures and
decreased moisture availability (Waters et al. 1994, Lemenih et al. 2004,
Wright et al. 2010, Yuan et al. 2013). Whilst native tree plantations are likely
to experience similar physical effects associated with canopy opening,
microclimates at the forest floor may more closely approximate those in
forests, as understorey buffers microclimates (Szarzynski & Anhuf 2001),
and native plantations better regenerate simplified native understories than
exotic plantations over time (Keenan et al. 1997).
Whilst sub-canopy microclimate has been examined many times in exotic
plantations, few studies have directly quantified the relationship between
indigenous vegetation, plantation structure and ground-level microclimates in
managed native plantations (Porté et al. 2004), or examined how these
change with plantation age. Such knowledge is important for foresters and
conservationists, as microclimate directly influences tree health through its
effects on soil and (Davidson et al. 2007), native tree plantations are
promoted as low-contrast buffers that reduce edge effects in forests (Denyer
27
Chapter 2: Plantation microclimate diversity
et al. 2006, do Nascimento et al. 2011; Prieto-Benez & Mendez 2011), and
manipulating plantation microclimates by changing vegetation structure is a
management technique currently being investigated as a means to directly
increase the conservation value of managed native plantations for plants and
animals (Carey 2003, Cummings & Reid 2008, Yuan et al. 2005, 2013). This
study aimed to compare the similarities between available microclimates in
young and old native plantation monocultures and adjacent managed logged
and old growth forests in the peak growing period of Spring-Summer, to
assess available thermal environment as a habitat selection cue.
Methods
Study area
Vegetation structure and associated thermal environments were
investigated in the Camden Haven and Macleay-Hastings river catchments,
on the mid-north coast of New South Wales, Australia, from October 2001 to
December 2003. The land in the area is a series of coastal mountain ranges
with maximum elevations of approximately 400 m in the south to over 1000 m
in the north. Mean annual rainfall is 1548mm at Wauchope in the
approximate centre of the study area (Fig 1). Temperatures ranged between
5.3° - 25.8°C between July and January. Native forests in the area vary from
sub-tropical rainforests to dry open hardwood forests, but dry eucalypt forests
predominate (Harden, 1991).
The study area contained hardwood plantations aged between 6 and
32 years old. The oldest plantations within the study area were monoculture
plantings of the endemic, dominant canopy tree species, Blackbutt
28
Chapter 2: Plantation microclimate diversity
(Eucalyptus pilularis), whilst young plantations were simple polycultures of
three species; (Eucalyptus pilularis, E. cloeziana, E. grandis). Twenty 200 x
300m field sites were spread over a 55 x 80km area of woodland, (max.
55.2km west of the coast; 31017’S 152035'E - 31042’S 152031'E), and were
matched in time since fire and logging, altitude, aspect and dominant canopy
tree species. Sites were selected to provide a replicated non-orthogonal
statistical design that standardized plantation age, planting density and
distance to native forest as much as possible within the constraints of the
existing plantations. Whilst native sites were adequately spread throughout
the study area, young and old plantation sites were necessarily clumped in
the Northern expanse of the study area due to the need to standardise
plantation age within a limited number of closely distributed plantations in the
landscape. Pseudoreplication was ameliorated by sampling at least two
separate plantations and by positioning all sites as far apart as possible
within an individual plantation. All plantation sites (except for spar plantations)
were separated by ≥1km of plantation matrix and were established in
separate stands of plantings. All sampling within sites occurred at ≥50m from
any edge, including snig tracks, dirt roads or plantation stand boundaries.
Forest types
Five forest types associated with timber production were identified in the
study area. These were old growth native forest, logged native forest, old
plantation, young plantation and early maturity (spar) plantation.
Young plantations (Fig. 2a) were situated in two 40 hectare plantations
established on land historically cleared as pasture, then afforested with
plantation in 1996-97. Establishment procedures included deep ripping, weed
29
Chapter 2: Plantation microclimate diversity
control and fertilization, and tree density was ~1000/ha. Since establishment,
no fires or thinning had occurred.
Young afforested plantations
Young plantations were comprised of three tree species E. pilularis (80%), E.
grandis (5%) and E. cloeziana (10%) planted in monoculture blocks.
Sampling in young plantations was restricted to stands of E. pilularis only.
The canopy was open with an understorey of dense stands of Imperata
cylindrica and patches of bracken (Pteridium esculentum). 40% of the
plantation margin showed broad connection to disturbed (grazing, fire) native
forest. All the sites were exposed to low intensity cattle grazing.
Spar plantations
Early maturity (also termed ‘spar’ by Florence, 1996) plantations (Fig.
2b) were small plantations of three species polycultures dominated by
Eucalyptus pilularis in similar percentages as outlined for early young
plantations. All sites in young and spar plantations were restricted to E.
pilularis stands only. The five replicate sites within spar plantations were
necessarily small (100 x 100m) due to the poor representation of plantations
of this age in the Mid North Coast plantation estate at the time of sampling.
Sampling in these plantations was restricted to microclimate only. The two 20
ha plantations in this treatment were planted in 1991 and underwent
establishment procedures similar to those in both young and old plantation
treatments. Sites in this forest type were exposed to low intensity cattle
grazing, and had not been thinned since establishment. Spar plantations
were unmanaged after the first five years of growth and were undisturbed by
30
Chapter 2: Plantation microclimate diversity
Fig. 1. A map of the 55 x 80km study area on the mid-north coast of New South
Wales. Sites are denoted by circles. YP = young plantations, OP = old plantations,
LN = logged native forests, ON = old growth native forests, SP = spar plantations.
The rectangular inset on the map (sourced from Gavran 2013) at the top left
identifies the North Coast bioregion in which the study was conducted.
31
Chapter 2: Plantation microclimate diversity
(a)
(b)
(c)
(d)
(e)
Fig. 2. Diagrammatic representation of the structural complexity of vegetation in (a)
young plantation, (b) spar plantation, (c) old plantations, (d) logged native forest,
and (e) old growth native forest.
fire, creating a forest type with a dense closed canopy. All plantation
treatments were matched in initial planting density.
Old reforested plantation
Sites were established in two 80 hectare monospecific plantations of E.
pilularis on land initial forested, then cleared and replanted in 1974 at a
32
Chapter 2: Plantation microclimate diversity
density of 150-200/hectare. In the first five years these plantations underwent
weed control and fertilization associated with accelerating tree growth.
Remnant shrubby vegetation was retained within the plantation along dry
gullies as two to five metre wide strips. Seed trees were not retained in these
riparian buffers, but shrubby vegetation was often well developed. Old
plantation sites did not support sub-canopy or mid-storey layers outside
riparian strips. Typically there was a high (+30m) canopy layer, and an
understorey ranging from very dense swathes of Blady grass (Imperata
cylindrica) to bare soil patches (Fig. 2c). Small, sparse patches of Acacia sp.
regrowth typically did not exceed 3m in height. The plantation was last
thinned in 1994 resulting in a very open canopy. Low intensity wildfire was
last recorded in the plantations in 1996. Seventy percent of the plantation
margin was broadly connected to managed native forest used for low
intensity cattle grazing, and thirty percent abutted logged native forest.
Logged native forest
Logged native forests represented the dominant forest in the
landscape. Sites had been subjected to recent (1996) and historic selective
logging. Tree species mixtures were dominated by E. pilularis. This forest
had been thinned by both small coup removal and selective logging, resulting
in a patchy, open forest canopy (Fig. 2d). Areas within this forest type where
thinning was less intense were characterised by large numbers of Casuarina
sp. The mid-storey was sparse where present, but the understorey,
particularly in old logging coups and along snig tracks had dense sedge
Lomandra longifolia, and Imperata cylindrica grass. As for old plantations,
33
Chapter 2: Plantation microclimate diversity
thinning and fire were excluded after 1996. Sites were wholly within extensive
forested areas with a similar management history.
Old growth native forest
Native forests throughout the region had a long history of selective
logging which spanned the last 100 years (Pitt, 2001). Commercial logging
throughout this region commenced in the late 1800s and increased in
intensity throughout and following the 1940s. The old growth native forest
sampled in this study had not been logged for a minimum of 40 years, and
represented the oldest closed-canopy forest within the study area. The forest
contained a mixture of sub-tropical and wet coastal woodland and rainforest
plants. Sites within this forest type were surrounded by logged native forest.
The trees in order of dominance included Eucalyptus pilularis, E. microcorys,
and Syncarpia glomulifera. There were well developed sub-canopy and midstorey layers (Fig. 2e) and the forest floor was typically bare with patches of
fallen, mossy logs, and mixed ferns and sedges (Lomandra longifolia, Gahnia
sp.).
Vegetation structure
Vegetation structure was quantified at five sites in young and old plantations and
logged and old growth forests. At each site vegetation characteristics were measured from
2
sixteen 15m quadrats along four haphazardly placed transects spaced 50m apart. Quadrats
were spaced 70m apart along transects. Four quadrats from four transects in each of five
sites resulted in a total of 80 quadrats per forest type. All sampling was conducted between
November 2001 and April 2002. The vegetation characteristics measured are shown in
Table 1.
34
Chapter 2: Plantation microclimate diversity
Thermal environment
The amount of global solar radiation available at ground level was assessed
using a pyranometer (model LP 02L, Campbell Scientific) that measured a
combination of ultraviolet, near-infrared and incident wavelengths of light.
The amount of insolation at the ground level was recorded from five sites in
each of the five forest types from three 50m transects spaced 30m apart in
an area at the centre of each site. Maximum insolation was sampled by
always choosing the brightest sun patch within a three metre radius of each
transect point, between 11:00am and 2:00pm. Samples were collected from
five points at ten metre intervals along each transect, three times during four
sequential, uniformly sunny days. A total of 45 measurements per site were
recorded from September 2001– February 2002. Brief snapshots of light
environments such as this have previously been shown to accurately predict
light environments within a season (Dignan & Bren 2003). The pyranometer
was positioned 20cm above the ground, and was allowed to equilibrate for
one minute before each measurement was taken. The pyranometer was
calibrated against a laboratory standard LI-COR quantum sensor and data
were adjusted accordingly before analysis.
Environmental temperatures measured as a combination of insolation
and air temperature were recorded from the hottest (full sun daily) and
coolest (full shade daily) microenvironments in all forest types, to determine
whether there were any differences in the daily range of available
temperature, and any seasonal shifts in this range.
35
Chapter 2: Plantation microclimate diversity
Table 1. Vegetation parameters and the methods used to record them from four forest types on the Mid North Coast of NSW.
Variable measured
Whole environment characters
number of trees
tree DBH
midstorey height
number of saplings
vertical complexity
Definition
Measurement
Method
count
length
height
tape measure
categorical
follow ing McDonald et al. 1990
percentage
percentage
percentage
visual estimate
visual estimate
height
range finder
amount of horizontal space covered by canopy foliage
percentage
standardised photographs
see McDonald et al . 1990
height of any vegetation up to 1.5m high
height
percentage
percentage
percentage
depth
percentage
percentage
percentage
count
ruler
Trees are defined as any vegetation taller than 5m high
tree girth at approx 1.4m above the ground
height to the midstorey canopy below the sub-canopy layer
range finder
count
an estimate of how much vertical space betw een the ground and the canopy
is occupied by foliage
foliage density between 0-1m above grnd. Foliage refers to any plant part and does not differentiate
foliage density between 1-2m above grnd. betw een species or grow th forms
foliage density between >2m above grnd.
Canopy level characters
crown height
height to the canopy top but excluding
visual estimate
emergent trees
canopy cover
Ground level characters
understorey height
shrub cover
grass cover
litter cover
litter depth
twig density
rock cover
bare ground
# fallen logs
shruby grow th forms only
grasses only
depth of leaves from the soil to the top of the leaf pack
how many tw igs < 1cm thick cover a 10 x10cm square
Logs w ere defined as any dead w ood on the ground surface w ith
visual estimate
visual estimate
visual estimate
ruler (cms)
visual estimate
visual estimate
visual estimate
diameter >5cm and length >15cm
log cover
log decomposition
number of stumps
soil moisture*
the total percentage of a quadrat covered by logs
a count of any holes/crevices in a log of >5cm long and 2cm w ide
included to quantify the availability of vertical perches/basking points
Laboratory study involving drying soil samples.
percentage
count
count
weight change
visual estimate
modified from Fletcher (1977)
gravimetric determination
Soil dried for 48hrs and change in w eight is equated w ith soil moisture content.
*soil samples w ere collected from 1 random point in each quadrat using a 5-cm diameter soil corer inserted to a depth of 10 cm after removal of the litter and humus layer.
36
Chapter 2: Plantation microclimate diversity
Thermocron iButtons (model DS1921L, Dallas Semiconductors) are microchipdriven data loggers sensitive to 0.250C fluctuations in temperature. IButton
loggers have stainless steel casing, and in this study were plastic wrapped and
painted with neutral-coloured paint (following Walsberg & Weathers, 1986) to
prevent heat reflection influencing recorded temperatures.
Four loggers were placed haphazardly within each microhabitat in each site,
such that no sampled microhabitat was less than 30m from any edge, no logger
was less than 50m from another and loggers remained wholly within the
microhabitat they were sampling. Loggers recorded temperature one centimetre
above the leaf litter surface every hour, for a period of three months throughout
the period of the study in which vegetation structure was measured (September
2001– February 2002) resulting in twenty samples per forest type. Loggers were
moved within microenvironments once per month to better sample the variability
associated with each microhabitat. To sample any temperature differences
associated with plantation aging four loggers were placed in sun and shade
microhabitat in each of four sites in spar and young plantations, resulting in 16
samples per microhabitat. Methods for logger placement followed those
described previously. Temperature was sampled from October 2002 to
November 2003.
37
Chapter 2: Plantation microclimate diversity
Data Analysis
Vegetation structure
Changes in vegetation structure associated with management history in
young and old plantations, logged and unlogged native forests were explored
using nonparametric multivariate analysis of variance, conducted on Bray-Curtis
dissimilarity matrices calculated on standardized data using the PRIMER
analysis package (Clarke 1993). Prior to analyses, multicollinearity between
vegetation variables was assessed, and the model run using only the least
correlated (≤r = 0.3) variables. Data was averaged over quadrats to create sitelevel means before analysis. Structural differences between young and old
plantations and forests were then tested iteratively by analysis of similarity
(ANOSIM). Vegetation variables driving the differences between forest types
were identified using similarity analysis (PRIMER - Clarke 1993). These data
were represented graphically in a principal co-ordinates biplot, using the BrayCurtis dissimilarity semi-metric as the distance measure as it deals well with
zero values, is less sensitive to skew and non-normality than the Euclidean
distance metric, and it implicitly standardizes data measured on different unit
scales (McArdle 1999).
Thermal Environment
Seasonal shifts and circadian differences in mean temperature were
analysed using fixed effects (forest type, month) two-way repeated measures
analysis of variance (RMANOVA) with contrasts specified to test for differences
38
Chapter 2: Plantation microclimate diversity
between young and old plantations, and logged and old growth native forests.
Data was averaged within sites then pooled into hourly time bins, generating
nine temperature recordings in the day (06:00- 18:00) and twelve at night
(18:00- 6:00) in each forest type. Sun and shade microhabitats were analysed
separately. Within subjects degrees of freedom were adjusted using a lower
bound test where the assumption of sphericity was violated (SPSS, 2003), and
so deviated from the expected k-1, N-k format. Oneway RMANOVA with the
same design protocols as above was used to identify any changes in
temperature between young and spar plantations. All data were log (x+1)
transformed before analyses. Circadian profiles were generated to visualise any
differences in mean available temperature between young and old plantations
and forests, and between young and spar plantations.
Linear regression was used to relate canopy cover, number of saplings,
grass area, shrub cover and foliage cover up to one metre above the ground to
thermal environment in plantations and forests. Subsequently, one-way analysis
of variance (ANOVA) was used to compare variation in mean maximum
temperature and insolation between forest types, and explain any variation
present. Bonferroni corrections for multiple comparisons were applied. The
vegetation variables analysed in regressions were those identified by similarity
analyses as characterising forest types, and that were likely to directly influence
both temperature and solar radiation penetration to the ground. Temperature
data were restricted to daytime measurements from sun microhabitats between
December and January, when temperature differences between forest types
39
Chapter 2: Plantation microclimate diversity
were maximal to avoid confounding seasonal with treatment effects. For all
analyses temperature and solar radiation data were pooled over sites then
transformed by square root or log (x+1) as necessary to satisfy test assumptions
before analysis. Relationships between thermal parameters and vegetation
structure were illustrated using partial regression and scatter plots.
Results
Vegetation structure
Vegetation structure differed significantly between forest types and
management histories within forest type (global R= 0.955, p=0.01). Structural
similarity was highest between old growth and logged native forests (average
dissimilarity [a.d] = 13.9%), whilst young and old plantations were less similar
(a.d. = 30.4%). The majority of the variance in the data was explained by
differences between plantation and forest vegetation structure (Fig. 3, Dim 1 =
69.63%). Old growth native forests had the highest vertical complexity of all
forest types above two metres. Logged native forests were characterised by
high foliage density between 1-2m and dead wood on the ground (Fig. 3). Young
plantations lacked sub-canopy complexity and had a grassy ground layer
interspersed with rocky and bare patches (Fig 3). Mean canopy cover was the
same in plantations (20%) and increased (50%) in logged native forests. In
particular the lack or development of canopy cover, foliage cover 0-1m above
the ground, number of saplings and number of trees was important in defining
individual forest types.
40
Chapter 2: Plantation microclimate diversity
Environmental temperature
In addition to circadian fluctuations in temperature there was a global
increase in temperature of ~100C degrees in all microhabitats between
September and February. During the day mean temperatures in sun (F3,16=
336.710 p<0.001) and shade (F3,16= 20.458 p<0.001) microhabitats differed
between forest types. Plantations were thermally distinct from forests between
10am – 5pm in the sun microhabitat, and logged forests were intermediate
between plantations and old growth forests. Young plantations were
consistently ~100C hotter than logged forests, ~200C hotter than old growth
forests, and ~ 50C hotter than old plantations in the hottest three hours of the
day from November - January (Fig. 4 a - c). At night old growth forests
remained between 2 - 50C cooler than any other forest type in shade
microhabitats (F3,16= 4.795 p=0.014), but temperatures were equivalent in sun
microhabitats in all forest types (F3,16= 0.431 p= 0.734). Young plantations were
exposed to the greatest temperature range throughout the period of
measurement, as daytime mean maximums moved from ~30 - 480C between
September and January. In comparison old plantations and logged
forests experienced temperature increases of ~100C and old growth forests
~80C (Fig, 4 a-c).
41
Chapter 2: Plantation microclimate diversity
Fig. 3. Principal co-ordinates biplot showing the distribution of vegetation variables in
relation to forest type using Bray Curtis semi metric distance separation on transformed
vegetation data. Only the top 45% of the explanatory vectors are shown. Symbols
represent: filled circles = old growth native forest, open circles = logged native forests,
filled squares = old plantations, open squares = young plantations.
Age-related thermal differences in plantations
Spar plantations differed from young plantations by having taller trees and
a very dense closed canopy, but an understorey structurally similar to young
plantations, with patchy grass cover on the ground and no shrub or sub-canopy
layers. Whilst young and spar plantations experienced similar mean
environmental temperatures in the morning, young plantations were
significantly ~80C) hotter between 10am and 5pm (F1,30= 6.373 p= 0.017) (Fig.
5a). This temperature difference did not persist in shade microhabitats during
the day (F1,30= 2.642 p= 0.115), or at night (sun: F1,30= 0.501 p= 0.484, shade:
42
Chapter 2: Plantation microclimate diversity
F1,30= 0.1.917 p= 0.176) despite young plantations cooling to ~20C cooler than
spar plantations (Fig 5b-d).
Table 2. Results of within-subjects tests for the repeated measures analysis of variance
test on environmental temperature data from old growth and logged native forests and
old and young plantations. ‘Time’ expresses changes in temperature over the course of
a day.
Time of day
6AM - 6PM
F
df
p
time*forest type
month
month*forest type
month *time
9.502
483.418
3.173
10.597
3,16
1,16
3,16
1,16
0.001
<0.001
0.053
0.005
time*forest type
month
month*forest type
month *time
5.191
202.245
2.693
2.396
3,16
1,16
3,16
1,16
0.011
<0.001
0.081
0.141
time *forest type
month
month*forest type
month *time
2.247
222.363
2.221
1.883
3,16
1,16
3,16
1,16
0.734
<0.001
0.125
0.189
time *forest type
month
month*forest type
month *time
12.917
301.828
1.743
2.364
3,16
1,16
3,16
1,16
<0.001
<0.001
0.199
0.144
Sun
Shade
6PM - 6AM
Sun
Shade
43
Chapter 2: Plantation microclimate diversity
Fig. 4 Circadian profiles for mean environmental temperatures available in the sun and
shade throughout the course of the day from 6am to 6pm, between September and
January in forests and plantations. Data is pooled across sites within microhabitats and
averaged within time categories. Graphs (a) – (c) depict available temperature in sun
microhabitats, whilst graphs (d) – (f) depict those in shade microhabitats. Error bars
represent +/- 1 SE. Symbols represent the four forest types: filled circles = old growth
native forest, open circles = logged native forests, filled squares = old plantations, open
squares = young plantations.
44
Chapter 2: Plantation microclimate diversity
Fig. 5. Circadian profiles for mean environmental temperatures available in spar and
young plantations in the sun and shade throughout the course of the day. Graph (a) =
sun microhabitat, 6am to 6pm, (b) = shade microhabitat, 6am to 6pm (c) = sun
microhabitat, 6pm-6am, (d) = shade microhabitat, 6pm-6am. Error bars represent ± 1SE.
Open squares = young plantation, filled triangles = spar plantations
Table 3. Results for analyses relating vegetation variables with maximum solar
radiation levels and maximum available environmental temperatures occurring in young
and old plantations, logged and old growth native forests between 6am – 6pm.
Significant values are in bold. Notations are: OP = old plantation, YP = young plantation,
LN = logged native forest, ON = old growth native forests.
ANOVA
overall
insolation (Wm -2)
F
df
p
74.945
3,16 <0.001
0.003
0.95
OP v LN
<0.001
<0.001
OP v ON
<0.001
<0.001
r2
0.837 14.375
canopy cover
grass area
sapling density
shrub cover
foliage cover 0-1m
r2
<0.001 0.861 17.308 5,14 <0.001
<0.001
0.033
0.495
0.792
0.524
0.991
0.249
0.049
0.284
0.451
pairwise OP v YP
Regressions
model
temperature (0C)
F
df
p
42.384 3,16 <0.001
5,14
45
Chapter 2: Plantation microclimate diversity
Relating vegetation structure and thermal environment
Overall ground-level microclimates received significantly less solar
radiation and were cooler as canopy cover increased from young plantations to
old growth native forests (solar radiation:F5,14 = 14.375, p<0.00, r2 = 0.837;
temperature: F5,14= 17.308 p<0.001, r2 = 0.861, Fig 6a-b). Insolation levels
differed between each forest type, with old plantations receiving the highest level
of insolation (Fig. 6 c-d). However, whilst available temperatures also differed
between plantations and forests (Fig. 6 a-b, Table 3) they were similar between
young and old plantations, suggesting non-linear correlation between
temperature and insolation. Canopy cover was the only vegetation parameter
tested that significantly affected both insolation levels and available temperature
at the ground, and shrub cover significantly affected available temperatures at
the ground during the day.
46
Chapter 2: Plantation microclimate diversity
Fig. 6. (a) and (b) are scatter plots depicting the distribution of canopy cover with forest
type. (c) and (d) are partial regression plots showing the strength of the linear
relationship between the transformed radiant energy and environmental temperature
variables and canopy cover, with the other variables associated with the multiple
regression accounted for. Unbroken lines represent the linear line of best fit. Broken
lines represent the 95% confidence intervals around the line of best fit.
Discussion
This study demonstrated that historical management can have a strong
and ongoing influence on vegetation structure in native timber plantations and
forests, and that in plantations canopy opening associated with management
can dictate the thermal environment available at the forest floor. The structural
uniqueness of plantations and forests in this study was generated by differences
47
Chapter 2: Plantation microclimate diversity
in canopy cover, sapling density, shrub and grass cover. Unsurprisingly, the
greatest degree of structural difference lay between native forests and
plantations, and strong fidelity within plantations and forests as groups was
driven by specific structural variables: grass in plantations and vertical
complexity forests. Opening of the tree canopy significantly increased daytime
temperatures, and plantations experienced lighter, hotter and less stable
microhabitats at the ground than native forests during the day. While insolation
was controlled by canopy cover alone, shrub density moderated available
temperatures at the ground.
Vegetation structure in old plantations and logged native forests
Previous land use can strongly affect vegetation communities (e.g. Ito et al.
2004, Gachet et al. 2007). Whilst young timber plantations necessarily present a
very different structural environment to forests, in this study plantations of 30
years old supported much less structural complexity in the understorey and were
so distinct from logged native forests that had experienced equivalent time since
fire and harvesting, equivalent grazing exclusion and equivalent access to the
original forest seedbed and to seed dispersal from adjacent forests. The lack of
understorey regeneration in old plantations despite these similarities suggests
that a combination of abiotic and biotic factors was likely to have interacted to
reduce vegetation complexity. Fire was unlikely to be the cause of the lack of
complexity in old plantation understories as low intensity fires mobilize soil
nutrients and so stimulate plant growth (Gill et al. 1981). In this study
management associated with pole harvesting or thinning had been excluded for
48
Chapter 2: Plantation microclimate diversity
a similar time prior to study commencement. However, lower canopy cover in
old plantations (20% versus 50% in logged native forests) suggests that the old
plantations had experienced harvesting more frequently than logged native
forests, and it is likely that relictual effects of soil compaction associated with
harvesting may have affected seedling germination and growth (Kozlowskia
1999). Further, the high density of Blady grass (Imperata cylindrica) which is
often associated with degraded soils and high temperature and light
environments, and is known to be allelopathic (Coile & Shilling 1993), may have
inhibited native regeneration through competition.
Environmental temperature
Temperature is a dynamic property of forests (Saunders et al. 1998), and
this study highlights that temperature is dynamic at both macro and micro scales.
Environmental temperatures differed significantly between all the forest types
assessed in this study in both sun and shade microhabitats during the middle of
the day, but were cooler in shaded microhabitats in forests at night. Higher
daytime temperatures in plantations than forests have been identified by Denyer
et al. (2006) at plantation edges, and by Malcom (1998) and Weng et al. (2007)
in thinned exotic plantations. However Porté et al. (2004) failed to find this
difference between old plantations and those thinned 10 years prior to his study,
and explain this as an effect of temperature buffering by the forest. Such
buffering is also likely to drive temperature differences at night.
As plantations heated and cooled rapidly throughout the day, there was
an expectation that they would cool rapidly during the night, and potentially
49
Chapter 2: Plantation microclimate diversity
reach a lower minimum temperature than forests as heat was lost through the
open canopy (e.g. Clinton et al. 2003). However in this study, as for that of those
of Denyer et al. (2006) and Baas and Mennen (1996), night temperatures were
equal in forests and plantations in open microhabitats, but were cooler in forests
in shaded microhabitats. Manipulative studies have identified that sub-canopy
structural complexity buffers air temperatures and may prevent the temperature
fluctuations associated with large canopy openings (Carlson & Groot, 1997).
Thus whilst shaded microhabitats in the old growth forests received the least
insolation and were coolest, vegetative buffering meant that at night they were
retained the low temperatures achieved during the day, rather than equalizing
temperatures as was occurring in the more open sun microhabitats, and on a
larger scale in the very open plantations. Baas and Mennen (1996) highlight that
temperature differences are often seasonal, and that in summer night may be
too short to allow temperatures to drop from high daytime levels.
Young native plantations possessed distinct thermal environments in the
study area, and so had high potential to influence to potential colonizers.
Microclimates associated with young plantations were likely to exclude those
forest organisms that lacked a tolerance for large fluctuations in temperature
and irradiance. Forest understorey plants which represent the readiest source of
propagules for young native plantations abutting native forests were not
exposed high daily temperature fluctuations. For many plants high light high
temperature environments may limit germination, growth and survivorship (e.g.
MacDonald & Thompson 2003, Dang & Cheng 2004). Thus plants colonising
50
Chapter 2: Plantation microclimate diversity
young plantations may be limited to those species that can withstand relatively
large diel and seasonal temperature shifts.
Thermal environment and vegetation structure
Gradients defined by solar radiation and environmental temperature only
loosely followed the structural complexity of vegetation in this study. Although
there was a general decrease in insolation and temperature as structural
complexity increased, levels of insolation in young and old plantations were
similar, as were temperatures in old plantations and logged native forests,
despite significant structural differences between these three forest types.
Saunders et al. (1998) and Pritchard and Comeau (2004) identify that
temperature structure is often distinct from vegetation structure in managed
forests. In this study there was a complex, non-linear relationship between
vegetation structure and thermal environment, which was probably related to a
combination of vegetation removing specific elements of solar radiation by
shading (Holl, 1999; Kotzen, 2003) and wind. Various studies recognize that
wind and understorey vegetation influence forest temperatures (Morecroft et al.,
1988; Palik and Engstrom, 1999; Rambo & North, 2008). Understorey
complexity can reduce wind flow in forests and allow air mixing (e.g. Chen et al.,
1995; Chen & Franklin, 1997; Novak et al., 2000) which results in higher and
more stable air temperatures. In this study such mixing may have stabilized
temperatures in old growth forests, while the lack of mixing explains the labile
nature of plantation temperatures.
51
Chapter 2: Plantation microclimate diversity
The similar circadian profiles of environmental temperatures in logged
native and old plantations are likely to represent a convergence of thermal
conditions generated by different means, rather than a similarity of the
mechanisms producing them. Old plantations received very high irradiance at
the ground resulting in high environmental temperatures. In logged native
forests high canopy cover decreases irradiance at the ground level, but complex
understorey increases air mixing, which may result in buffered air temperatures
approximating those in old plantations. Results support this idea: it is only during
summer that environmental temperatures in plantations and logged native
forests converge, when all the forest types are exposed to seasonally higher
irradiance. Similar insolation in young and old plantations is more linearly related
to canopy cover (e.g. Yirdaw &Luukkanen, 2004). Plantations supported simple
understorey and had equally open canopies, which resulted in equivalent
amounts of light attenuation in both forest types.
Plantation aging and effects on environmental temperature
Spar (12 years old) plantations had increased canopy cover and were
colder than young (6 years old) plantations. This result documents the typical
thermal sequence observed in plantations, of cooling at canopy closure and
associated low understorey diversity (Florence, 1996). Spar plantations
represent a short-lived stage in the plantation cycle before the canopy is opened
by subsequent harvesting, but they may have large ramifications for fauna. For
those forest fauna that prefer cool thermal environments but are tolerant of
simple structure (e.g. Mott et al., 2010) spar plantations could represent a
52
Chapter 2: Plantation microclimate diversity
valuable habitat resource. From a management perspective if this stage of
plantation is promoted within the landscape mosaic at forest-plantation
boundaries, it may provide forest species with accessible habitat, as well as
buffering forest from the microclimatic extremes experienced in young and old
plantations.
Management recommendations and research
Importantly this study indicates that monoculture and simple polyculture
hardwood plantations support a warmer and more varied microclimate than do
native forests, even native forests that have been heavily disturbed. For animals,
the labile nature of the environmental temperatures in logged native forests and
plantations are likely to have ramifications for those species that use them,
particularly species of low mobility. The large magnitude of differences in both
structure and thermal environment in plantations are likely to impact strongly on
fauna and plants as habitat selection cues, and may exclude species from
plantations seasonally. Further, because these differences persist in plantations
as they age and are exacerbated by current management practices, plantations
may not represent faunally diverse habitats throughout the length of a rotation.
In order to increase the conservation value of plantations, managers will need to
support the microclimatic needs of specific groups of organisms, and modify
management practices to provide both structurally and thermally attractive
habitat features for these organisms. Focusing further research on seasonal
shifts in microclimate would allow managers to better understand thermal regime
in plantations, and so target management strategies to increase diversity. For
53
Chapter 2: Plantation microclimate diversity
example, Kluber et al. (2009) identify that different log sizes offer a variety of
thermal refuges that allow seasonal persistence of salamanders in thinned
forests. If these measures were adapted and adopted in Australian plantation
forests they may result in significant biodiversity gains. A focused analysis of the
biota using spar plantations needs to be conducted and should be prioritized, as
much of the Australian hardwood plantation estate is now entering this growth
stage. If adopting conservation and management practices that promote and
maintain functionality is important to forest managers, thermal environments in
native plantations need to be specifically recognised as having a strong potential
to influence biodiversity.
54
Chapter 3: Plantations and fauna
Chapter 3
Faunal response to young and old eucalypt
plantations: do consistent patterns exist across
animal taxa?
Introduction
Investigating patterns of response to habitat change that are consistent
across different faunal groups is a unifying approach to fauna conservation in
disturbed landscapes. Vegetation structure in forests heavily influences physical
and chemical environments (e.g. Leite et al. 2010, Zhao et al. 2011). If forest
structure changes with land use and management, faunal communities
associated with specific forest environments may also change. Often this
change is a decline in cross-taxa species richness with increasing habitat
simplification (e.g. Dunn 2004, Schulze et al. 2004, Scott et al. 2006).
Native monoculture tree plantations are a highly simplified and rapidly
proliferating (FAO 2010) environment which may more closely approximate
native forest than exotic plantations (Brockerhoff et al. 2012), and so may better
support fauna (Sala et al. 2000, Lindenmayer & Hobbs 2007). There is a
growing body of research that suggests that native plantations better meet the
ecological needs of native species than do exotic plantations (Potts et al. 2001,
Becker et al. 2007). As such native plantations represent a topical model system
in which to investigate faunal response to forest simplification across animal
taxa.
55
Chapter 3: Plantations and fauna
Studies that compare animal species richness between simplified native
plantation environments and forests often provide conflicting results. Whilst bird,
plant and invertebrate species richness have been reported as declining in
native plantations (Hobbs et al. 2003), equivalent richness generated by
compensatory responses of fauna (e.g. Frederickson & Frederickson 2002,
MacDonald et al. 2002, Woinarski & Ash 2002, Barbaro et al. 2005, Fonseca et
al. 2009) are also reported. Further, while forest specialists are often lost from
native plantations (e.g. Moore & Allen 1999, Kanowski et al. 2005), in the
presence of high amounts of mature forest in the landscape and matrices of low
contrast, large numbers of forest species can persist (e.g. Pardini et al. 2009,
Volpato et al. 2010). Whilst there is no clear consensus that reduced structural
complexity in plantations decreases species richness across multiple animal
taxa, it is generally accepted that planted forests are less valuable for
biodiversity than natural forests (Brockerhoff et al. 2012). Further, whilst young
plantations are thought to be less likely to support fauna due to the immediate
effects of plantation generation, there is some research suggesting that young
plantations may support faunal diversity (e.g. Sullivan et al. 2009). This research
addresses the role of age in influencing faunal use of managed plantation
habitats. It aims to identify whether there are any consistent patterns of faunal
response to young afforested and old reforested native tree monocultures
across animal taxa by:
1) comparing species richness and assemblage structure of fauna using native
eucalypt forests of differing management age, with those using plantations of
56
Chapter 3: Plantations and fauna
endemic tree species of different age but equivalent time since management,
and
2) examining the difference in ecological function of plantation assemblages by
comparing the distribution of feeding guilds across mammal, bird and
herpetofaunal taxa, between plantations and native forests.
Materials and Methods
Faunal communities were surveyed in parts of the Camden Haven and
Macleay-Hastings river catchments in the North Coast Bioregion of New South
Wales, Australia, from September 2001 to March 2002 (Fig.1). Mean annual
rainfall in the area was 1548mm at Wauchope in the approximate centre of the
study area over the period of sampling. Temperatures achieved a mean
minimum of 5.3° C in July and mean maximum of 25.8° C in January. Native
forests in the area varied from sub-tropical rainforests to dry open hardwood
forests, but dry eucalypt forests were dominant (Harden 1991). The study area
contained hardwood plantations aged between 6 and 32 years old. The 32 year
old plantations in the study area were monoculture plantings of the endemic,
dominant canopy tree species, Blackbutt (Eucalyptus pilularis), whilst 6 year old
plantations were simple polycultures of three species; (Eucalyptus pilularis, E.
cloeziana, E. grandis). Habitat descriptions for each of these forests types are
presented in chapter two. The landscape mosaic surrounding plantations
consisted of cleared, grazed pasture, grazed E. pilularis -dominated woodlands,
57
Chapter 3: Plantations and fauna
tall closed woodlands, and closed-canopy, sub-tropical rainforest. All sites were
established on Triassic tuff soils in the study area. E. pilularis was the dominant
canopy-level or emergent tree species at all sites. As described in chapter two,
twenty 200 x 300m field sites were spread over a 55 x 80km area of woodland,
(max. 55.2km west of the coast; 31017’S 152035'E - 31042’S 152031'E), and
were matched in time since fire and logging, altitude, aspect and dominant
canopy tree species. Sites were selected to provide a replicated non-orthogonal
statistical design that standardized plantation age, planting density and distance
to native forest as much as possible within the constraints of the existing
plantations.
Habitat Descriptions
Four forest types with differing disturbance histories were identified: old
growth native forest, logged native forest, old plantation established on cleared
and subsequently reforested eucalypt woodland and young plantation
established on reclaimed pasture. Chapter two provides details of each forest
treatment. Analysis of vegetation structure (chapter two) identified that each
forest type was structurally distinct, with native forests having dense tree
canopies and sub-canopy complexity, while young and old plantations lacked
sub-canopy complexity and had grassy ground layers. Table 1 outlines some of
the defining structural characteristics of each forest type.
58
Chapter 3: Plantations and fauna
Table 1. Means (± 1se) of vegetation variables sampled from 16 x15m2 quadrats in
twenty sites in old growth native forest, logged native forest, old plantation and young
plantation forest types, in NSW Australia between 2001 and 2002.
Forest
Old Growth native
Logged native
Old plantation
Young plantation
tree¹
crown
Time since
Age management (y) density
height (m)
+100
+50
195 ± 8.5 39 ± 4.7
+70
6
166 ±10.4 27 ± 1.1
32
6
51 ± 7.6
28 ± 0.6
6
6
216 ± 4.4
10 ± 0
foliage²
cover
40 ± 4.6
63 ± 5.4
83 ± 5.0
95 ± 0.7
grass³
cover
2 ± 1.7
30 ± 5.2
75 ± 5.5
86 ± 1.2
leaf³
litter
96 ± 5.4
58 ± 3.0
24 ± 5.4
6 ± 1.2
canopy 4
cover
1175 ± 27
816 ± 63
277 ± 27
283 ± 21
¹ number of trees per 15m2
² % cover of foliage up to 1m above the ground, excluding foliage associated with saplings and trees
³ % mean cover of grass within each quadrat
4
% of canopy covered by tree crown identified using standardised photographs (McDonald et al. 1990)
All vegetation measuresments are presented ± 1 se.
Sampling methodologies
Five 200 x 400m sites (as described in chapter 2) were established within
each forest type at least 50m from any roads, and in plantations 50m from dry
gullies with retained riparian vegetation or remnant trees. All sites were
approximately 1 kilometer apart to minimize the possibility that ground fauna
captured would travel between sites, and so acted as independent replicates.
Surveys were conducted over spring and summer (Aug. 2001 to Mar. 2002), and
sampling effort was spread evenly across forest types to accommodate for any
seasonal shift in faunal activity. Data was collected for one season and so could
not contribute to questions about annual fluctuations in assemblage structure.
Pitfall Trapping
Pitfall traps were used to sample ground-living terrestrial vertebrate fauna.
A single trapping grid composed of three trapping arrays was installed at each
site. A trapping array consisted of four buckets arranged along the compass
axes around a fifth central bucket. Traps (20L buckets) were buried level with
59
Chapter 3: Plantations and fauna
the ground surface. Distal buckets were placed five metres from the central
bucket. Two 35cm high, 10m long fences of black polythene were erected along
the north-south and east-west axes of each array so that they each stretched
across three buckets, and intersected over the central bucket. The bottoms of
fences were buried into the ground so animals could not pass underneath.
Arrays were situated at least 150m from each other within a site, to minimize the
possibility of sequentially recapturing individual animals. Animals caught in pit
traps were measured and individually, inconspicuously paint-marked to identify
recaptures.
Traps were initially opened for five nights, and re-opened six weeks later
for a second five night trapping period (December 2001 and March 2002). Three
arrays totaling 15 traps, for each of five sites, opened for 10 nights resulted in a
total of 750 trap days per forest type. Traps were cleared once per day in the
mornings and, after processing, all animals were released at the site of capture.
Diurnal Bird Census
I conducted all surveys over a five month spring/summer period
(September 2001 to January 2002) for four non-consecutive days at each site.
Birds censuses involved continuous slow walking (~1.4km/hr) along a 1.5 km
randomly oriented line transect through the midpoint of each site. At each site
two surveys beginning at 05:30h, and two at 06:45h were conducted, to coincide
with the maximum pre- and post-dawn bird activity. All birds identified visually
and aurally within a ten metre band either side of the transect line were recorded.
60
Chapter 3: Plantations and fauna
Each forest type was surveyed for 23 hours in total (4.6 hours for each of five
sites per forest type).
Small Mammal Trapping
A grid of Elliott traps (each 35x12x15cm) was established in each site.
Thirty traps were laid out in a grid of five transects spaced 80m apart, with each
transect bearing six traps spaced at 40m intervals. Traps were placed in
positions that facilitated their attractiveness to small mammals (rock crevices,
against logs) and baited daily with a mixture of peanut butter, oats, honey,
salami and vanilla essence. Traps were opened for five consecutive nights each
trapping period. Traps were cleared in the early morning, and animals caught
were identified, measured and individually marked before release at the site of
capture. Thirty traps opened for five nights in five sites resulted in a total of 750
trap nights in each forest type. Trapping was staggered in time between
replicate sites to avoid bias associated with the onset of the wet season.
Trapping commenced in November 2001 and finished in March 2002.
Spotlighting
Spotlighting surveys were conducted on separate nights to record the
presence of nocturnal birds, mammals and herpetofauna. Four, foot-based
spotlighting surveys were conducted along tracks within each site, and involved
continual slow walking at ~0.75km/hr along a 1.5km transect. Tracks meandered
within sites but were consistently directed east south-east. All animals identified
within 15m either side of the transect line were recorded. Surveys were
61
Chapter 3: Plantations and fauna
conducted between December 2001 and March 2002 at an effort of 20 survey
nights per forest type.
Species characteristics
To identify any direction of change in ecological function between forest
types and across taxonomic groups, primary diet and foraging strata were
compiled from species accounts in the literature (Birds Australia 1991-2007,
Strahan 1995, Cogger 1996, Greer 2005, Barker et al. 1995). Firstly, to identify
the character of the fauna using each forest type, each species was assigned to
a group defined by major habitat preference. ‘Forest’ specialists were restricted
to closed forest, ‘woodland’ specialists used woodland and open forest
environments and ‘generalists’ used all forest types. Habitat categories were
purposefully broad to encompass ecological characters that occurred
consistently across animal taxa. Feeding resource guilds were then defined by
combining two variables; primary diet (seven categories: carnivore, herbivore,
nectarivore, omnivore, granivore, insectivore, frugivore) and foraging stratum
(six categories: all strata, all strata excluding the ground, canopy/subcanopy
only, midstorey (>10m above the ground)-canopy, ground-low (0-2m above the
ground, ground). Foraging stratum was defined as the stratum in which the
majority of foraging behaviour occurred. Unlike other guild-based analyses,
guilds were defined by combining diet and foraging characteristics because the
interaction between these more accurately represented how a species was
using habitat, and so generated a guild structure that was adequately descriptive
across taxonomic groups. This resulted in twelve unique bird feeding guilds, five
62
Chapter 3: Plantations and fauna
herpetofaunal guilds and four mammal guilds (Appendix 1). Reptiles and frogs
were pooled for guild analyses because diet and foraging stratum overlapped
strongly for both taxa. The two possum species and one megabat representing
the nectarivore/herbivore-arboreal guild were excluded from data sets to restrict
analyses to ground mammals only.
Data analysis
After satisfying assumptions one-way analysis of variance (ANOVA) was
the used to test for differences in the mean richness and abundance of birds,
mammals , reptiles and frogs in old and logged forests, young and old
plantations using SPSS v 21 (SPSS, 2012). All data was pooled across
transects, averaged over sites and log (x+1) transformed. Two-way ANOVA was
used to identify any change in the richness of habitat specialists (closed forest,
open forest, generalists; Appendix 1) with forest type. Pairwise comparisons with
Bonferroni corrections were generated to test for differences between forest
types. Analysis of similarity (ANOSIM, PRIMER: Clarke, 1993) was used to
identify any change in assemblage structure between young and old plantations
and logged and old growth native forests for each faunal group using presenceabsence transformed, standardized abundance data with a species by site
matrix. A guild-by-site matrix was then generated and ANOSIM repeated to
identify which, if any, guilds were lost in plantations. Changes in the relative
abundance of guilds between forest types were analyzed separately for birds
and mammals and herpetofauna using presence-absence transformed,
standardized species richness data. All ANOSIMs used Bray-Curtis dissimilarity
63
Chapter 3: Plantations and fauna
matrices and were iterated 2000 times. Pairwise comparisons between forest
types were tested as part of ANOSIM. All analyses were considered significant
at the p=0.05 level.
Results
Fauna sampling produced 3781 individual records of 2962 birds from 70
species, 157 frog captures from 5 species, 388 mammal records from 12
species and 453 reptile captures from 26 reptile species. Appendices one and
two provide a species list for these captures. Collectively the total number of
species recorded represented 28% of the total 408 terrestrial species recorded
from the bioregion by the NSW Atlas of Wildlife (NSW NPWS, 2001).
Distinct bird, mammal and herpetofauna assemblages of equivalent
species richness and abundance were identified from each forest type sampled
(Tables 2 + 3) despite significant differences in vegetation structure between
forest types (Chapter 2). All taxa displayed non-significant trends towards lowest
mean species richness and abundance in plantations generally and in young
plantations in particular (Fig. 1a, b), apart from birds whose mean abundance
was lowest in old plantations. For birds non-significant differences in abundance
between forests and plantations (Fig. 1b) were driven by high variability in
abundance in native forests.
64
Chapter 3: Plantations and fauna
Figure 1. Mean raw species richness (A) and abundance (B) of birds, mammals and
herpetofauna sampled from four forest types on the Mid North Coast of New South
Wales, Australia. Bars represent old growth forest (black bars), logged native forest
(grey bars), old plantation (stippled bars) and young plantation (open bars). All error
bars represent the 95% confidence interval around the mean.
65
Chapter 3: Plantations and fauna
Table 2. Results of ANOSIM analysis comparing the assemblage structure of birds,
mammals and herpetofauna sampled from twenty field sites in four eucalypt forest
types on the Mid North Coast of New South Wales. Global R values and p values
indicate whether assemblage structure differs between forest types and associated
pairwise comparisons identify where differences lie. Values in bold are p>0.05.
Abbreviations for forest types are ON = old growth native forest, LN = logged native
forest, OP = old plantations, YP = young plantations.
Birds
Global R p≤
0.726 0.001
pairwise comparisons
ON vs LN
ON vs OP
ON vs YP
LN vs OP
LN vs YP
OP vs YP
0.406
0.926
0.980
0.558
0.828
0.728
0.016
0.008
0.008
0.008
0.008
0.008
Herpetofauna
Global R p≤
0.665 0.001
0.828
0.948
0.808
0.464
0.728
0.548
0.008
0.008
0.008
0.016
0.008
0.008
Mammals
Global R p≤
0.556 0.001
0.520
0.564
0.720
0.524
0.740
0.380
0.008
0.008
0.008
0.008
0.008
0.040
Habitat specialization
Birds
Forest birds comprised half of the 70 bird species identified in this study,
and dominated forested habitats. Whilst young and old plantations supported 53%
and 51% of all bird species, significantly fewer forest birds were recorded in
plantations, and forest species were replaced by woodland specialists and
generalist birds (Table 3, Fig. 2a). Interestingly habitat specialists (as defined in
Appendix 1) occurred in young plantations (17%) with similar frequency to old
growth forest (19%) and at higher frequency than in old plantations (5%),
suggesting that young plantations represented preferred habitat for some
species, particularly grass and canopy feeders (Appendix 1).
66
Chapter 3: Plantations and fauna
Table 3. Results of ANOVAs comparing log transformed count data for species
richness, abundance and species by habitat specialization for birds, mammals and
herpetofauna from twenty sites in four forest types on the mid north coast of New South
Wales, Australia. Values in bold are significant at the p <0.05 level.
F
d.f.
p≤
Birds
Mammals
Herpetofauna
3.063
0.611
1.53
3,16
3,16
3,16
0.073
0.617
0.251
Birds
Mammals
Herpetofauna
2.722
3.067
2.156
3,16
3,16
3,16
0.448
0.144
0.288
13.482
14.183
6,60
6,60
0.001
0.001
13.428
6,60
0.001
Richness
Abundance
Richness x specialisation
Birds
Mammals
Herpetofauna
Herpetofauna
Significant differences in herpetofaunal assemblage structure between all
forest types (Table 2) were driven by the strong association of individual species
with particular forest types. 43% of all species were restricted to old growth
forests and only 8% of all species occurred in four forest types. Young
plantations failed to support 89% of forest specialist herpetofaunal species, and
in both young and old plantations forest specialists were replaced by generalists
(Fig.2b). This result contrasted that of birds, where woodland specialists rather
than generalists replaced forest species in plantations. Notably, while young
plantations supported 44% of all reptile species, only one species occurring at
high abundance was restricted to this forest type (Appendix 1).
67
Chapter 3: Plantations and fauna
Figure 2. Mean species richness of birds, mammals and herpetofauna grouped by
habitat preference sampled from twenty sites in four forest types on the Mid North
Coast of New South Wales, Australia. Bars represent forest specialists (black bars),
generalists (open bars) and woodland specialists (stippled bars). All error bars
represent the 95% confidence interval around the mean. Total mean richness on the y
axis varies for each animal taxon.
Mammals
The distribution of mammalian habitat specialists differed significantly
amongst forest types (Table 2, Fig. 2c). A diverse suite of forest mammals were
restricted to old growth forests (Appendix 1). Woodland specialists were absent
68
Chapter 3: Plantations and fauna
from old growth forests and most species rich in plantations. Both young and old
plantations supported similar mammal richness. Similar to birds, assemblage
fidelity was generally low for mammals, with 23% of all mammal species being
trapped in all four forest types. The only mammal restricted to young plantations
was the exotic house mouse (Mus musculus).
Cross-taxa comparisons of guild structure
Bird guilds differed significantly in species richness between all four forest
types sampled (Table 3). Forests consistently supported a higher a richness of
arboreal and ground-feeding insectivores, and carnivorous species foraging at
all levels. Old plantations were dominated by canopy-feeding insectivores, and
young plantations by generalist and ground-feeding insectivores and canopyfeeding frugivore/omnivores (Fig 3a). In opposition to birds, herpetofaunal
feeding guilds differed only between logged forests and young plantations
(Table 4), primarily due the higher diversity of ground-feeding carnivores
(snakes) and the lack of insectivores, primarily arboreal snakes and geckos, in
young plantations (Fig. 3b). Despite small numbers of mammal species trapped,
there was a consistently greater richness of ground-feeding insectivores in old
plantations than in logged native forests (Table 4, Fig 3 c). In contrast young
plantations supported a marginally higher (but non-significant) richness of
ground-feeding omnivores than old plantations (Fig. 3c).
69
Chapter 3: Plantations and fauna
Figure 3. Total species richness of A) bird, B) herpetofauna and C) mammals guilds sampled from twenty field sites on
the Mid North Coast of New South Wales. Each guild is defined by foraging stratum and primary diet. Foraging strata are
A = all strata, G = forages at 0m, G-L = using all understorey vegetation from 0-2m, C = using primarily tree
canopy/subcanopy only, Ar = uses any strata except the ground. Diets are C = carnivore, C/I = carnivore/insectivore, O =
omnivore, F/I= frugivore/insectivore N/I = nectarivore/insectivore, N/F/I = nectarivore/frugivore/insectivore, I= insectivore,
F/O = largely frugivorous but some omnivory, G = granivore. Bars represent old growth forest (black bars), logged native
forest (grey bars), old plantation (stippled bars) and young plantation (open bars).
70
Chapter 3: Plantations and fauna
Table 4. Results of ANOSIM analysis comparing the diversity of feeding guilds of birds,
mammals and herpetofauna sampled from twenty field sites in four eucalypt forest
types on the Mid North Coast of New South Wales. Global R values and p values
identify whether guild structure differs between forest types and associated pairwise
comparisons identify where differences lie. Values in bold are significant at the p>0.05
level. Abbreviations for forest types are ON = old growth native forest, LN = logged
native forest, OP = old plantations, YP = young plantations.
Birds
Global R p≤
0.565 0.001
pairwise comparisons
ON vs LN
ON vs OP
ON vs YP
LN vs OP
LN vs YP
OP vs YP
0.596
0.320
0.772
0.604
0.780
0.452
0.008
0.048
0.008
0.016
0.008
0.008
Herpetofauna
Global R p≤
0.218 0.029
0.140
0.398
0.324
0.006
0.344
0.120
0.159
0.056
0.087
0.444
0.024
0.214
Mammals
Global R p≤
0.296 0.001
0.468
0.380
0.118
0.560
0.280
0.204
0.032
0.032
0.206
0.016
0.087
0.135
Discussion
This research identified that simplifying native forest structure through
logging and plantation development did not decrease the overall species
richness of birds, mammals, or herpetofauna at the stand scale, but significantly
decreased the species richness of forest fauna from all taxa. Whilst this
research concludes that young native plantations can be as species diverse as
old growth native forests, it is important to recognize that this statement is untrue
for forest specialist fauna, and for this faunal element, both young and old
plantations may represent poor habitat.
Patterns of richness
Old growth native forest was equivalent in mean richness to logged native
forest, 32 year old reforested and six year old young afforested plantation, and
71
Chapter 3: Plantations and fauna
this response to habitat simplification was consistent across taxonomic groups.
This result supports those of Borsboom et al. (2002) whose research in small
scale eucalypt plantations in moderate proximity to forests identified similar
richness between plantations older than four years and forests. Faunal richness
is likely to increase in plantations where the dominant tree species is endemic, if
plantations present an environment that closely approximates some aspects of
native forest (e.g. biophysical environment, feeding substrates, food resources,
leaf litter structure - Strauss 2001). In this research the relatively small size of
plantations, the use of local endemic tree species, broad connection between
plantations and forest, and the retention of key habitat features are all likely to
have promoted high species richness in young and old plantations. The
juxtaposition of these elements may represent a scenario in which native
plantations can achieve high faunal diversity. However as the work of Hobbs et
al. (2003) and Kavanagh et al. (2005) in native plantations in fragmented forest
systems in Australia attest, in the presence of a regional species pool negatively
affected by native forest fragmentation, even large-scale native plantations
remain depauperate in comparison to forest remnants.
Plantation age is a recognized determinant of diversity (Munro et al.
2007), and previous research has consistently identified young plantations as
poor habitat for rainforest reptiles (Kanowski et al. 2006), birds and arboreal
mammals (Borsboom et al. 2002, Kavanagh et al. 2005, Munro et al. 2007). But
in this study, neither age nor land use history decreased mean richness in any
animal taxon. This was unexpected for birds and herpetofauna, as both taxa are
72
Chapter 3: Plantations and fauna
highly sensitive to changes in habitat structure (Brown & Nelson 1993, Boone &
Krohn 2000, Garden et al. 2007), and birds are documented as responding
negatively to managed plantations less than five years old (Baguette et al. 1994,
Klomp & Grabham 2002, Kavanagh et al. 2007). Similar species richness
between forests and young plantations have previously been documented only
where there is a developed under/mid-storey (Loehle et al. 2005a, Loyn et al.
2007), and both Zurita & Bellocq (2010) and Sax (2002) suggest that bird
species richness may often be temporally and spatially stable regardless of the
dominant vegetation type in the presence of understorey complexity. However,
in this research plantation understories were not highly complex. Instead habitat
enrichment measures which have been demonstrated to increase species
diversity in native plantations (Law & Chidel, 2002, Dent & Wright 2009, Hsu et
al. 2010), are likely to have interacted with forest proximity to increase the
attractiveness of plantations, and hence overall species richness. For frogs,
reptiles and ground mammals which have lower mobility and strong reliance on
small-scale site characteristics, in this study where both landscape context and
site-specific characteristics promote habitat use, young plantations supported
diverse faunal assemblages.
Assemblage structure and ecological function
In this research forest species were lost from all taxa in both young
and old plantations. This loss commonly drives changes in the distribution of
guilds (birds - MacArthur et al. 1962, Pearman 2002, Díaz et al. 2005;
mammals- Fox 1985; reptiles - Attum et al. 2006, Urbina-Cardona et al. 2006).
73
Chapter 3: Plantations and fauna
Plantations consistently lost arboreally foraging birds, mammals and
herpetofauna (Table 5). There was a replacement of forest species with
woodland species and specialists with generalists across all taxa in response to
habitat simplification and increase in canopy openness. This response has
previously been well documented as a response to plantations by birds (Hansen
1995, Christian et al. 1998, Munro et al. 2007), reptiles (Gardner et al. 2007b)
and mammals (Jenkins et al. 2003, Holland & Bennett 2007), as driven by
species-specific preferences for habitat structure. Reduced guild diversity
directly reduces the resilience of systems (Luck et al. 2003), as well as having
flow on effects on nutrient cycling, pollination, insect population dynamics and
seed dispersal, processes which play a strong role in vegetation regeneration in
agricultural landscapes (e.g. Archibald et al. 2011).
Birds
In this study habitat generalists represented a high proportion of the
mammal and particularly reptile species using young plantations. However, even
after 25 years of growth and management old plantation reptile assemblages
were still heavily dominated by generalists, and birds were the only taxon to
experience significant species replacement with woodland species rather than
generalists in young and old plantations.
74
Chapter 3: Plantations and fauna
Table 5. A summary of the ecological character of birds, mammals, and herpetofauna
sampled from ten field sites in eucalypt plantations on the mid-north coast of New South
Wales.
Ecological character
Species richness declines in
plantations
Birds
No
Herpetofauna Mammals
No
No
Abundance declines in
plantations
No
No
No
Site fidelity
Low
High
Low
Forest species lost from
Yes
plantations
Arboreal species lost from
Yes
plantations
Increased dominance of
Yes
generalist species in plantations.
Yes
Yes
Yes
Yes
Yes
Yes
Increase in woodland species in Yes
plantations
Yes
Yes
Loyn et al. (2007) also identified native plantations as supporting woodland birds,
which is positive news for woodland birds that are currently in decline in many
parts of Australia (Paton & O’Connor 2010). However, if native plantations make
landscapes more permeable to bird dispersal (Gascon et al. 1999, Lindenmayer
& Franklin 2002, Gardner et al. 2007b) this may increase competition between
forest birds and generalist or woodland birds moving into forested environments.
Whilst highly competitive species such as Noisy Miners (Manorina
melanocephala) and Indian Mynas (Acridotheres tristis) were not recorded in
this research, these issues need consideration before the impact of the native
afforestation on birds can be properly understood.
This research and that of Borsboom et al. (2002) identified that old
plantations supported canopy-feeding insectivorous birds that were absent from
young plantations, but lacked high abundances of frugivores or nectarivores
75
Chapter 3: Plantations and fauna
common in native canopies. This suggests simplification of resource-availability
in the canopy has long-term negative effects on guild structure, despite the high
mobility of birds and the close proximity of old plantations to remnant native
forest.
Ground Fauna
The association of different reptile and mammal assemblages with
specific forest types is likely to be driven food or refuge availability for mammals
and by thermal environment for herpetofauna (Zhao et al. 2006). Herpetofaunal
assemblages in this study were distributed in relation to the thermal
microclimates available in colder old growth native forest and hotter young
plantations (Chapter 2). The young plantation assemblage included thermophilic
snakes and lizards, while lizard species requiring high habitat complexity and
cool thermal environments were common in old growth forests. The lack of
cryptozoic species in old plantations reflected the lack of structural complexity
on the ground resulting from long-term plantation management, and suggests
that the retention of complex features like coarse woody debris may increase the
diversity of both forest and woodland species in old plantations.
The separation of mammal species into different assemblages with
change in habitat structure is common (e.g. Mengak & Guyunn 2003, Kavanagh
& Stanton 2005). Whilst mammals have been documented as occurring at lower
abundance and species richness in exotic plantations (Lindenmayer et al.1999,
Sax 2002), in ecologically-managed native plantation monocultures that retain
preferred habitat features, small mammals can be as diverse as they are in
76
Chapter 3: Plantations and fauna
forests (e.g. Fonseca et al. 2009). Holland and Bennett (2007) and Ramírez and
Simonetti (2011) suggest that species specific-preference for vegetation
structure can be more important than forest type in determining the presence of
specific mammal species. In this study small mammal richness and abundance
in plantations equaled that of forests, as species replacement by incursions of
woodland and generalist small mammals with preferences for less complex
understories balanced forest species loss.
Whilst forest mammals were abundant in old plantations, their abundance
was significantly reduced in in young plantations. Mitchell et al. (1995)
suggested that in their comparison of pine forest-pine plantation ecosystems,
forest species maintained a presence in young plantations due to local extinction
and recolonisation. In this study at least two forest mammals were considered
resident in old plantations as they were observed carrying young, although given
the low abundance of most forest species it is probable that local population
extinction as suggested by Mitchell et al. (1995), or seasonal use of young
plantations, was occurring. Clarifying the terms of residency of ground fauna in
young plantations requires a longer-term investigation in young plantations, and
should include an assessment of seasonal change.
The role of plantations in offsetting species loss
This study demonstrated that young native monoculture plantations
established on previously cleared farmland can increase local biodiversity, and
in the presence of biological legacies and close proximity to forests, young
afforested plantations can support a diverse array of species. In this scenario,
77
Chapter 3: Plantations and fauna
young plantations show potential as a forest management practice that can
increase the local biodiversity of vertebrate fauna. Notably, in this research
plantations supported assemblages of birds and mammals listed by the NSW
Department of Environment and Heritage as vulnerable in the Macleay-Hastings
sub-region of the Northern Rivers Catchment Management Authority region.
Given the current development of broad-scale afforestation with native
plantations, this study suggests that as the native plantation estate matures it
may provide significant positive benefits to woodland fauna. However,
advocating that plantation monocultures have conservation value must be
tempered by recognition that landscape context strongly influences faunal use of
plantations. Further, whilst young and old eucalypt plantations in this study
supported diverse faunal assemblages of birds, mammals and reptiles, many
species occurred at very low abundance, and plantation assemblages were
consistently dominated by generalists and woodland specialists. The
environment available in plantations is likely to provide both physiological and
behavioral barriers that disadvantage many forest species, and so plantations
may have little value when the conservation of forest species, particularly
ground fauna, is a priority.
Quantifying the effect of historical land use on plantation environments is
an inherent part of assessing the conservation significance of native plantations
for fauna. Land use history influences vegetation structure (Raymond 2008,
Bremer & Farley 2010) and faunal use of native forest regrowth (Bowen et al.
2007, Cunningham et al. 2007), and so may have strong potential to affect
78
Chapter 3: Plantations and fauna
species diversity in monoculture plantations. It is probable that in plantations
managed for timber production, management will often outweigh the effects of
land use history in the short term, as management has an immediate effect on
vegetation structure and thus habitat quality (e.g. Klomp & Grabham 2002). Prior
land use may affect current faunal use of plantations if historical isolation has
compromised the quality of biological legacies as habitat, these habitat features
play a focal role in promoting faunal diversity in plantations (e.g. Pharo &
Lindenmayer 2009, Hsu et al. 2010). Clarifying the effects of prior land use may
only be possible as the plantation estate matures, but needs to include an
assessment of the role of biological legacies (e.g. Lindenmayer et al. 2009,
Barrientos 2010) in increasing plantation diversity.
79
Chapter 4: Invertebrate resources and ground fauna
Chapter 4
The influence of invertebrate prey availability on
ground-dwelling insectivores
Introduction
Plantation forests are an important part of the forest estate in many
countries, and are increasingly recognized as important to faunal diversity in
forested landscapes. However, our ability to predict the responses of
ecological communities and individual species to environmental changes, like
plantation development, remains a key issue for ecologists and conservation
managers (Williams et al. 2010, Planque et al. 2011). Research in native
plantations has been dominated by particular fauna, notably those useful as
biological indicators such as ants, beetles, birds and small mammals. Despite
the fact that many of the vertebrates using native plantations are
insectivorous, research focused on the invertebrate prey base available in
these forests is scarce. One reason for this research gap may be that, as for
vertebrates, invertebrate responses to the plantation environment can vary
among and within orders and species, making general predictions difficult.
Generally, plantation forests are expected to support less diverse
invertebrate communities than natural forests, due to the low plant species
diversity associated with monocultures (Knops et al.1999, Cunningham et al.
2005) and the scarcity of preferred habitat features like coarse woody debris
on the ground (Carey & Harrington 2001, Owens et al. 2008). But how this
relates to ecological processes that influence vertebrate use of plantations is
not clear. Research linking insectivores with prey availability (e.g. Lunney et
80
Chapter 4: Invertebrate resources and ground fauna
al. 2001) and quantifying how both prey base and predator abundance
changes in response to habitat alteration is essential if we want to identify the
quality of plantations as habitat for insectivores.
Prey Availability
Prey availability is one of the primary indicators of habitat quality for
many animals. It has been demonstrated to affect community structure
directly by allowing survivorship (e.g. James 1994) and indirectly by
influencing predator body size (e.g. Laparie et al. 2010), niche breadth (e.g.
Costa et al. 2008, Garcia-Barros & Benito 2010), life history (Forsman 1996),
competitive ability and ultimately fitness (e.g. Dickman 1988). The ability of
predators to adapt to changes in prey availability depends on the degree to
which they can vary their diets to accept other prey (Hodgkison & Hero 2003),
which in turn is constrained by behavioural flexibility (e.g. Lescroёl et al. 2010)
and morphological constraints like bite force (Herrel et al. 2007).
Both prey size and intractability, defined by Evans and Stanson (2005)
as the biomechanical properties of a food that confer structural strength,
stiffness and toughness, may strongly influence the attractiveness of prey,
and so indirectly influence habitat use. Prey size affects feeding decisions by
individuals by constraining predator attack rates (Hjelm & Persson 2001),
while at the community level it can determine population structure by defining
trophic links (Troost et al. 2008). There is a general trend for larger animals
to eat larger prey (e.g. Fisher & Dickman 1993, Lima et al. 2000) because
bite force and gape increase with head size (Herrel et al. 2001, Anderson et
al. 2008). Similarly, as prey size increases so does intractability. However
81
Chapter 4: Invertebrate resources and ground fauna
intractability is an important attribute of prey choice in its own right because it
affects chewing (Evans & Stanson 2005) and swallowing. Intractability has
been examined to understand the evolution of phenotypic differences (Herrel
et al. 2009) and niche partitioning (Dumont et al. 2009) within populations of
insectivores, but is less often cited as a factor that may influence habitat
occupancy. However, because intractability could constrain both passive
(gape limited predators) and active prey selection mechanisms if it decreases
food profitability by increasing handling time, it has the potential to influence
the types and numbers of species that may use a habitat. Thus
understanding the intractability of an invertebrate prey base as well as its
abundance, may help to define the resource quality of a habitat, and hence
its attractiveness to insectivores.
Predators, prey and plantations
The composition and distribution of epigaeic invertebrates can be
influence the diversity of insectivores such as small mammals, reptiles, birds,
and microbats, and as such provide a means to link insectivores from several
taxa. As for vertebrates, epigaeic invertebrate communities are often strongly
linked to available habitats defined by plant diversity (e.g. Hunter et al. 2000,
Taniguchi et al. 2003). The microhabitats associated with commercial
hardwood plantations differ from native forests due to tillage and
maintenance procedures that change soil, sub-soil profiles and simplify
understorey structure (Marcos et al. 2007, chapter 1), and changes in canopy
structure that influence thermal environments (Martius et al. 2004, Chapter 2).
Because of this, the potential of plantations to support a different community
82
Chapter 4: Invertebrate resources and ground fauna
of invertebrate prey is high. In the last decade work exploring invertebrate
ecology in plantations has identified that invertebrate communities do not
respond predictably to habitat simplification (Bird et al. 2004, Barbaro et al.
2005, Yu et al. 2008, Oxbrough et al. 2010). Whilst community structure
changes, communities using simplified habitats can be as diverse as those in
undisturbed habitats (e.g. Hodge et al. 2010), or can be dominated by a few
abundant insect orders with many other species occurring at low abundance
(e.g. Anderson & Death 2000, Bonham et al. 2002, Ratsirarson et al. 2002,
Cunningham et al. 2005). Typically, forest specialists (primarily beetles)
decline in young plantations, while generalists or open-area users like
spiders increase (Oxbrough et al. 2010). This shift in prey type coupled with a
trend towards increased body size in plantations (for beetles at least –
Cunningham & Murray 2007), suggests that plantations may not offer food
resources of a similar quality to those in forests. From a feeding ecology
perspective the potential of hardwood plantations to support vertebrate
insectivores will result from the breadth of predator prey preferences, and the
composition and palatability of the invertebrate community in residence.
However, to the present date there has been very little formal investigation of
what sort of prey base native plantations support in comparison to native
forest, and how this relates to vertebrate diversity in native plantations.
Chapter three of this thesis identified that the structurally simple
plantation environments assessed in the study area supported reptile and
mammal assemblages that were equally as species rich as forest
assemblages, but that showed trends towards reduced abundance. This
result contrasts those of Hobbs et al. (2003), Kanowski et al. (2006) and
83
Chapter 4: Invertebrate resources and ground fauna
Ramírez and Simonetti (2011) which identified managed native plantations
as supporting significantly fewer mammal and reptile species at less
abundance than forests. This chapter relates the availability of invertebrate
food resources in young and old plantations and logged and old growth
native forests with the abundance of insectivorous mammals and
herpetofauna, as an explanation for high vertebrate richness in plantations
Methods
Invertebrate sampling
Pitfall traps were used to collect ground-dwelling invertebrates from
logged and old growth native forest and old and young plantations between
November and February in 2001 and 2002. See chapter two for a description
of the study area the four forest types sampled. Although pitfall traps are a
poor measure of absolute abundance and density of invertebrates (du Bus de
Warnaffe & Dufrêne 2004), they are equally biased towards mobile epigeal
invertebrates, and when trapping is conducted over a small time scale, they
provide an effective means of measuring the relative importance of
invertebrates for comparative studies (Neumann 1991).
A 40 by 50 m grid of six transects each containing five traps (30
traps/site), was installed at the geographic centre of each of five 375 x 400m
sites in each treatment. Traps were opened once in each site for four
consecutive days resulting in 600 trap days per forest type in total. Each four
day period constituted one sample. Sampling effort was interspersed
between sites types and distributed across the eight months of the sampling
to minimize temporal bias in results. Pitfall traps (10cm diameter, 15cm depth)
84
Chapter 4: Invertebrate resources and ground fauna
were buried level with the ground surface and protected from incident rain by
a 25 cm diameter round plastic plate suspended 15 cm above the trap. Traps
were filled with 80ml of 80% ethylene glycol as preservative and 2ml of
detergent to lower the surface tension of the water. Invertebrates were
removed from the preservative using a 400µm sieve, and were subsequently
stored in 70% ethanol until sorting. Trapping occurred at the time of peak
invertebrate activity, as some invertebrates were likely to be quiescent under
bark or in logs or soil in the winter. Further some of the vertebrates recorded
from the study area are torpid in cooler months of the year, and as I wanted
to relate prey availability to vertebrate diversity it was necessary to trade off
accurate richness estimates against an examination of seasonal changes in
the abundance of food resources. Although seasonal changes in resource
abundance are important because they can lead to diet switching and
changes in competition (Becker et al. 2007), assessing the quality of
plantations as a winter refuge was outside the scope of this study.
To augment sampling and minimise any bias associated with trap size,
additional invertebrates were collected daily by hand from 15 x 20L, 35cm
diameter pitfall traps for four days per trap over two trapping periods in 2001
and 2002 (trapping described in chapter 3). All invertebrates longer than two
millimetres were collected. These samples were analysed separately to the
small pit trap samples to identify any effect of trap size.
Invertebrates were identified to order. The level of identification was
appropriate for this study because I was interested in the value of a species
in terms of its physical properties rather than its identity. The length of each
individual was measured from the tip of the frons without including any
85
Chapter 4: Invertebrate resources and ground fauna
protrusive mandibles, spines or antennae, to the posterior tip of the abdomen
using a used a stereomicroscope (Leica MS5) with a graticule (limit of
measurement 0.01mm). Larger specimens like several species of
Gryllacridoidea were measured using vernier calipers. Identification followed
Zborowski and Storey (2003) and CSIRO (1991). As per Lima et al. (2000)
body length was considered to indicate prey attractiveness as it can constrain
capture rates (e.g. Fisher & Dickman 1993) and swallowing times (e.g. Lima
et al. 2000).
Invertebrate hardness
Intractability was categorized by assigning invertebrates a hardness
score based on cuticle thickness. Cuticle thickness was measured for those
specimens larger than four millimeters from a flat 2 x 2 mm section of
sclerotized cuticle dissected from the hardest/ thickest part of the body
(elytron or thorax). Five individuals from each morphospecies from the twelve
dominant orders were measured using a digital micrometer (±1µm) (as per
Evans & Stanson 2005). The mean of these values was rounded to the
nearest single figure. Intractability was measured for the twelve abundant
orders including the Amphipoda, Arachnida, Blattodea, Coleoptera,
Diplopoda, Diptera, Hemiptera, ants, Orthoptera, Dermaptera and
Lepidoptera adults and larvae. Results were grouped into classes; 1: 1030µm, 2: 30-60µm 3: 60-90µm 4: 90-110µm 5: ≥110µm. All Acarina were
granted an intractability score of one because they were too small to
measure cuticle thickness in, and were likely to represent soft prey given
their relative size to the insectivores sampled.
Vertebrate sampling
86
Chapter 4: Invertebrate resources and ground fauna
Small mammals were sampled using pitfall traps and metal live traps
(Elliott traps – 38 x 12 x 11 cm). Live trapping occurred in conjunction with
pitfall trapping between December and March in 2001, and was repeated
between October and January 2003. Chapter three describes the methods
used for pitfall and live trapping in detail. Traps were opened between 16:00
and 08:00EST for five consecutive nights, resulting in a trapping effort of 750
trap nights/forest type. Traps were baited with a mixture of rolled oats, peanut
butter, honey, vanilla essence and salami. All animals captured were
released at the trap site after paint marking the bottoms of feet or to identify
recaptures. The pitfall trapping procedures and effort (750 trap nights x forest
type) followed those described in chapter 3.
Relating Predators and Prey
Fourteen of the 35 insectivore species trapped in this study were
excluded from analyses as they possessed kinetic jaws, were only
insectivorous at juvenile life stages or had strong preferences for forest
habitat features precluding their use of plantations (Appendix 2). Of the
omnivores, the Northern Brown Bandicoot Isoodon macrourus was excluded
as invertebrates were unlikely to control its distribution due to high levels of
mycophagy, but house mice (Mus musculus) and native rats (Rattus fuscipes,
R. lutreolus) were included as they were known to be insectivorous during
Spring-Summer when this study was conducted (Watts & Braithwaite 1978,
Cheal 1987).
87
Chapter 4: Invertebrate resources and ground fauna
Table 1. The distribution of mean gape sizes and prey size category used by insectivores sampled from four forest types on the Mid North
Coast of New South Wales. The maximum insectivore gape was calculated from snout-vent lengths of field-caught individuals, and
determined the prey size range available to each species. Diet preference data come from Fisher & Dickman 1993, Dickman 1988, Green
1989, Lima et al. 2000, Lunney et al. 1989, 2001, Vinyard and Payseur 2008, Williams et al. 2009. All measurements are in millimeters.
Preferred forest lists the forest type in which each species was most abundant. In this study Abbreviations for forest type are OP- old
plantation, YP – young plantation, LN – logged native forest, ON – old growth native forest.
Predator
Taxa
Group
Herpetofauna Small
Small
Small
Small
Small
Small
Medium
Medium
Medium
Medium
Large
Large
Large
Mammal
Small
Small
Medium
Medium
Small
Large
Large
Species
Adrasteaiscincus amicula
Lampropholis delicata
Lampropholis guichenoti
Crinia signifera
Pseudophryne coriacea
Uperolia fusca
Amphibolurus muricatus
Calyptotis ruficaudata
Ctenotus robustus
Lerista muelleri
Cyclodomorphus gerrardi
Limnodynastes peroni
Tiliqua scincoides
Snout-Vent
Length
30.00
40.00
40.00
23.00
23.00
25.00
80.60
47.40
100.00
58.00
200.00
65.00
300.00
Mean
gape
3.22
4.68
4.68
8.72
8.72
9.48
10.61
5.76
13.44
7.31
28.04
24.68
42.64
Planigale maculata
Sminthopsis murina
Antechinus stuartii
Antechinus swainsonii
Mus musculus
Rattus fuscipes
Rattus lutreolus
Weight (g)
6.58
18.00
23.43
51.30
15.53
96.07
120.45
15.00
22.40
17.40
28.40
12.50
23.00
31.00
Preferred prey Available prey
size range
size range
1-5
5-10
1-10
10-15
1-10
10-15
1-15
15-20
1-15
15-20
1-15
15-20
5-20
1-5
5-15
1-5
2-20
20-25
1-10
10-15
25-50
15-25
25-40
15-25
25->50
15-25
1-15
5-25
15-25
15-35
5-15
20-30
20-40
15-40
25->50
5-10,25->50
5-10,35->50
1-5
5-20
5-20
Dominant
Feeding Mode
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Insectivore
Omnivore
Preferred
Forest Abundance
YP
59
OP
265
YP
175
OP
15
OP
248
OP
23
YP
24
LN
51
YP
18
ON
26
ON
9
YP
35
OP
14
Insectivore
OP
Insectivore
OP/YP
Insectivore
ON
Insectivore
LN
Omnivore, granivore
YP
Omnivore, mycophage
ON
Omnivore
OP/YP
20
27
205
9
67
427
69
88
Chapter 4: Invertebrate resources and ground fauna
The species included in the data set were grouped by body size into the
groups: small, medium and large herpetofauna, small and medium dasyurids,
small and large rodents.
Decisions about what length of invertebrate represented a potential
prey item were made by referring to published accounts of prey size for the
species encountered (Green 1989, Lunney et al. 1989, 2001, Littlejohn et al.
1993, Barker et al. 1995, Wapstra & Swain 1996, Lima et al. 2000, Greer
2005). When this information was lacking predator gape size was used to
determine which invertebrates were available as potential prey. This
approach was used rather than a more direct analysis of faecal pellets, as
preliminary analyses determined that invertebrate fragments in pellets of
small lizard species (0.3-0.5g) were too small to infer prey length (e.g.
Angelici et al. 2007, Bos & Carthew 2007). For herpetofauna gape was
calculated from the modal snout-vent lengths of all individuals of each frog
and lizard species included in this study. Gape size was adjusted to account
for body shape using the equations of Lima et al. (2000) who have generated
correction factors for biometric gape size-body size relationships in small
Australian frogs and lizards. Mammal prey size preference of the same
species or of species with similar body size and habits were determined in
previous research by Fisher & Dickman 1993, Dickman 1988, Green 1989,
Hanson et al. 2007, Vinyard and Payseur 2008 and Williams et al. 2009.
Invertebrates were assigned to mutually exclusive categories as being
either preferred (preferentially eaten), available (outside of the preferred prey
range) or unavailable (not able to be eaten) on the basis of insectivore gape
size. For herpetofauna preferred prey were defined as those whose length
89
Chapter 4: Invertebrate resources and ground fauna
were 50% of the maximum gape, which in frogs and lizards is the portion of
the gape in which significant bite force is applied (Druzinsky & Greaves 1979).
Whilst rats chew their food (Cox et al. 2012) bite force is optimized at 40-50%
of the maximum gape (Williams et al. 2009), so preferred invertebrates were
defined as those whose lengths were 40% of the recorded maximum gape,
where published mean and maximum prey lengths did not exist. For all
insectivores available prey was defined as any invertebrate length that was
10% less than the minimum preferred prey size, and that was between the
top end of the preferred prey range and the maximum gape. However,
because dasyurids orient, chew and dismember their food all prey lengths
represented available prey for all species except Planigale maculata which
was estimated to be constrained to prey less than 40mm long due to its small
size. After defining the preferred and available prey ranges for each species
the size classes of invertebrates falling within these ranges were assigned to
each predator group (Table 1). Predator defense mechanisms like distasteful
secretions or poison were not accounted for because literature accounts of
species-specific preferences for certain prey types were often contradictory.
An unavailable prey was either below the recorded minimum preferred prey
size or above the maximal gape size.
90
Chapter 4: Invertebrate resources and ground fauna
Data analysis
Insectivores
As data could not be transformed to meet parametric test assumptions
and so allow posthoc testing, the relative abundance of small, medium and
large insectivores (Appendix 2) was compared between logged and old
growth forests and young and old plantations using the non-parametric
analysis of similarity (ANOSIM) procedure in Primer (Clarke 1993). BrayCurtis similarity matrices were generated using log x+1 transformed, columncentred abundance data. Multiple comparisons of each forest level were
performed on data bootstrapped 2000 times. All data were analysed at a
significance level of p = 0.05.
Invertebrates
After preliminary analyses showed that small and large traps
consistently sampled the same suite of invertebrates each year, both year
and trap size were removed as factors in the statistical models. Pitfall
trapping yielded 10653 individuals from 28 invertebrate orders. Orders that
occurred at less than 20 individuals in any forest type were excluded from the
data set because they were not considered abundant enough to drive
patterns of habitat use by insectivores . The 14 excluded orders accounted
for 2 percent of the total abundance.
To assess any differences in the abundance of invertebrates of
varying intractability between forest types and orders a two-way Analysis of
Variance (ANOVA) with forest type as fixed factors and order as a covariate
was generated. This analysis was repeated to assess differences in the
modal size of invertebrates in each forest. Data was normalised to meet test
91
Chapter 4: Invertebrate resources and ground fauna
assumptions using log x+1 transformation and Bonferroni correction was
applied to all posthoc tests for differences between forest types. The
available prey base in each forest type was assessed by analysing the
frequency of preferred, available and unavailable prey sizes using Chisquared tests for independence. Invertebrate data were grouped by
insectivore body size to allow meaningful comparisons across species. This
resulted in resulting in seven groups: small, medium and large herpetofauna,
small and medium dasyurids and small and large rodents. A separate Chisquared was performed for each group after verifying the assumptions of
Chi-squared were upheld. Bonferroni corrections were applied to identify
significant differences between forest types.
Results
Insectivores
Two years of trapping yielded a total 1978 captures of 5 frog, 21
reptile and 9 mammal species (Appendix 2). Plantations collectively
supported a marginally richer insectivore community than native forests (old
growth 20 spp., logged native 17 spp., young plantation 20 spp., old
plantation 21 spp.). After the exclusion of forest specialists a reduced data
set of 1786 captures from 20 species captures were analysed. The
abundance of large insectivores declined significantly moving from
plantations to forests, but both small and medium insectivores were similarly
abundant in logged and old growth forests and significantly more abundant in
plantations than forests (Table 2, Fig. 1).
92
Chapter 4: Invertebrate resources and ground fauna
Table 2. ANOSIM results testing for changes in small medium and large
insectivore abundance in each forest type. Significant differences at p < 0.05 are in
bold. ON = old growth native, LN = Logged native, OP = old plantation, YP = young
plantation.
Small
Global R
p≤
0.67
0
pairwise comparisons
ON v LN
0.224 0.079
ON v OP
0.508 0.016
ON v YP
1.000 0.008
LN v OP
0.504 0.008
LN v YP
1.000 0.008
OP v YP
0.852 0.008
Medium
Global R p≤
0.573 0.001
0.220
0.432
1.000
0.156
0.956
1.000
0.016
0.016
0.008
0.056
0.008
0.008
Large
Global R p≤
0.429 0.001
0.076
0.406
0.908
0.342
0.840
0.078
0.325
0.048
0.008
0.056
0.008
0.238
Figure 1. Cumulative abundances of insectivores from small, medium and large
body size groups sampled from old growth and logged native, and old and young
native plantations on the Mid North Coast of New South Wales. Letters denote
significant differences between forest types.
93
Chapter 4: Invertebrate resources and ground fauna
In young plantations large bush rats were replaced by swamp rats (Rattus
lutreolus) which occurred at very low abundance and were co-dominant in
this habitat with medium-sized house mice (Mus musculus). Mice were only
sampled from young plantations and comprised 18% of the individuals
captured in this forest type. Patterns within the dasyurids varied between
sizes. Only medium-sized Brown Antechinus (Antechinus stuartii) were
significantly more abundant in old growth forests than in either plantation
forest types. Small dasyurids were similarly abundant in logged native and
plantation habitats but avoided old growth forests, whilst large dasyurids
were generally rare and occurred only in logged native forests (Fig 1).
Young and old plantations were dominated by small herpetofauna,
particularly lampropholine litter skinks, but this assemblage was replaced in
old growth native forest by less abundant assemblages of cryptic skinks
(Appendix 2). Although large herpetofauna were rare they occurred at greater
frequency in young plantations than any other forest type. Generally
dasyurids, occurred most frequently in old plantations where they comprised
15-17% of the total number of individuals. In young plantations dasyurids
represented only 8% of the total number of captures.
Invertebrate prey
Whilst invertebrate hardness differed between invertebrate orders
(F13,54 = 119.03 p < 0.001) it did not differ between forest types (F3,54 = 0.039
p < 0.990) and so was subsequently dropped from all further analyses.
Similarly the mean size (forest - F3,54 = 0.059 p = 1.088, order – F1,54 = 0.078,
94
Chapter 4: Invertebrate resources and ground fauna
p = 1.443) and abundance (forest - F3,54 = 0.572 p < 0.248, order – F1,54 =
0.552, p = 0.548) of invertebrates within orders did not differ between forests
and plantations. There were non-significant trends for young plantations to
support high abundances of ants, millipedes, beetles, amphipods and
grasshoppers whilst native forest assemblages were dominated by mites,
beetles, flies, bugs and ants. Only hemipterans and ants showed trends
towards higher abundance in logged native and old plantation forests.
However, whilst the mean size and abundance of invertebrates did not differ
between plantations and forests, the frequency of invertebrates available to
and preferred by insectivores differed significantly between forest types
(Table 3). Preferred prey occurred most frequently in young and old
plantations for small and medium herpetofuana, medium dasyurids and small
rodents (Fig. 2, Table 3). Available prey for small dasuyrids and large rodents
were also trapped more frequently in plantations, however plantations
supported very little preferred or available prey for large herpetofauna (Fig. 2).
Table 3. Results of Chi-squared analyses and associated pairwise
comparisons for changes in the frequencies of preferred, available and unavailable
prey sampled from old growth and logged native forests, and eucalypt plantations on
the Mid North Coast of NSW. Abbreviations for forest types are ON = old growth
native, LN = Logged native, OP = old plantation, YP = young plantation.
Predator group
Small herpetofauna
Medium herpetofauna
Large herpetofauna
Small dasyurid
Medium dasyurid
Small rodent
Large rodent
χ2
1025.327
983.442
1084.933
540.179
172.201
983.442
143.805
d.f.
6
6
6
6
6
6
6
p
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
95
Chapter 4: Invertebrate resources and ground fauna
Fig. 2. The frequency of preferred, available and unavailable prey
present in each forest type for the seven predator groups analysed. Each
subscript letter denotes how the frequency of column proportions within
each forest category subset differs significantly at the .05 level. Bars
represent old growth forest (black), logged forest (grey), old plantation
(stippled) and young plantation (white).
96
Chapter 4: Invertebrate resources and ground fauna
Discussion
Young native plantations in this study supported a diverse epigaeic
insectivore community and significant food resources for ground-dwelling
insectivores. They supported similar abundances of invertebrates as logged
and old growth native forests, and higher frequencies of preferred prey sizes
for all insectivores than old plantations and native forests. Whilst this
distribution of preferred prey benefited small and medium-sized insectivores,
which were significantly more abundant in plantations than forests, large
insectivores did not effectively exploit high prey densities in plantations. For
large rodents in particular were uncommon where preferred and available
prey was abundant. If the habitats investigated in this study were saturated
and insectivores conformed to an ideal free distribution, individuals should
have aggregated in each forest type proportionately to the amount of
resources available in each (Fretwell & Lucas 1970). In this study insectivore
abundance was not so simply distributed. Many studies recognise the
importance of multiple cues for habitat selection, which often vary with
species (e.g. Fischer et al. 2004, Radford & Bennett 2007, Price et al. 2010).
In this study while the disjunction between prey availability and large
insectivore abundance may have been influenced by intrinsic factors
including breadth of habitat choice, diet, and preference for foraging optimally,
a variety of extrinsic cues including structural and thermal microhabitat
complexity and predation risk, may impinge more strongly on medium and
large, rather than small, species in plantations. This is because high levels of
management-associated disturbance in plantation environments are likely to
more directly impose constraints on the resources large predators require. In
97
Chapter 4: Invertebrate resources and ground fauna
particular, retreat sites which need to be large enough to provide refuges
adequate for predator avoidance and thermoregulation in the hotter (Chapter
2) plantation environment, are lost in plantations by active understorey
management and through grazing (Chapter 5). As several authors have
identified increased abundance in large ground mammals in plantations in
association with increased vegetation complexity at the ground level (coarse
woody debris- Loeb 1999, shrubs- Loyn et al. 2008), the lack of retreat sites
definitive of plantations in this study (Chapter 2) may limit the species
richness of large predators.
Predator Abundance
Small Predators
Prey availability was unlikely to constrain habitat use by small
insectivores in any of the four forest types examined in this study. Prey
preferred by small herpetofauna and dasyurids occurred frequently in all
forest types. Instead, other factors such as habitat preferences or predation
rates were likely to overshadow prey in driving patterns of habitat use. While
the abundance of small predators did not differ between forests, there were
strong trends towards plantations supporting higher abundances of small
lizards. Breadth of habitat choice, in particular, preferred temperature range,
may explain much of this pattern as Lampropholine lizards were the
dominant small predators. The most ‘generalist’ of these, Lampropholis
guichenoti and L. delicata are thermophilic (Spellerberg 1972, Greer 1980,
Chapter 6). Similarly despite the assertion of Wells (2010) that the smallerbodied Adrasteia amicula is associated with cooler habitats, in both this study
98
Chapter 4: Invertebrate resources and ground fauna
and that of Boorsboom et al. (2002), A. amicula was restricted to native
plantations and logged native forests, suggesting that it too may be
thermophilic, or strongly associated with open canopy, or both.
In this study small dasyurids (common dunnarts and planigales) were
not trapped in old growth forests despite an equal abundance of prey in all
forest types. While common dunnarts are likely to have been excluded from
native forests by a preference for dense grassy understoreys (Stokes et al.
2004), the absence of common planigales in old growth native forests despite
the high availability of palatable prey may result from competitive exclusion
by the medium-sized brown antechinus. Competitive exclusion resulting in
the displacement of smaller species is known to occur between small
dasyurids (Dickman 1988), unless diverse foraging microhabitats allow coexistence. In this study logged native forests supported the most diverse
foraging microhabitats which included shrub layers and high stem density
lacking in old growth native forests (Chapter 2),and were the only forest type
to concurrently support small (Planigale maculata, Sminthopsis murina) and
medium (Antechinus stuartii, Antechinus swainsonii) dasyurids. This result is
particularly important for plantation management as the Common Planigale is
currently listed by the New South Wales Department of Environment and
Conservation as vulnerable in the Macleay-Hastings catchment sub-region. If
management efforts aim to benefit this species in favoured habitats like
young and old plantations, retaining or protecting preferred habitat features
like grassy understoreys will be necessary at harvest or thinning.
99
Chapter 4: Invertebrate resources and ground fauna
Medium Predators
While medium-sized prey was abundant in plantations, medium-sized
dasyurids were rare, and were effectively replaced by the medium-sized
rodent, the introduced house mouse. The high abundance of house mice in
plantations is likely to result from an omnivorous diet and strong association
with highly cultivated landscapes (Singleton 1995) rather than the intrinsic
abundance of invertebrate prey in plantations. This numeric dominance by
mice over other rodents of similar body size was also identified by
Boorsboom et al. (2002) who found strong association between grassy
understorey, young plantations and house mouse abundance. Both
Boorsboom et al. (2002) and Caughley (2001) identified that mouse
abundance was much higher in winter, than summer, which suggests some
potential for the Brown Antechinus to be seasonally excluded from young
plantation, although Singleton (1995) suggests mice are poor competitors
with herbivores of similar size (e.g. Archibald et al. 2011). A winter influx of
mice into plantations may have knock-on effects for small lizards in
plantations, as mice were observed preying upon lizards on several
occasions in this study.
The disjunction between prey availability and predator abundance also
occurred in the medium-sized dasyurid, the Brown Antechinus and may have
resulted from a scarcity of retreats or of useable foraging substrates. While
Brown Antechinus did occur in young plantations their total abundance was
significantly higher in old plantations where their preferred prey was less
abundant, suggesting that the young plantation environment was less than
optimal for this species. If predators were to forage optimally they should
100
Chapter 4: Invertebrate resources and ground fauna
consume the biggest prey possible for the best energetic return (see review
by Pyke1984). Whilst a preferred prey range exists, the available prey range
for the generalist Brown Antechinus was large due to its ability to process
food by chewing and stretching (Fisher & Dickman 1993) and generalists will
readily exploit prey sizes outside the preferred range to avoid competition
with other insectivores (e.g. Dickman 1988). As Brown Antechinus are
strongly opportunistic foragers, and prey switching in this species is common
(e.g. Green 1989, Lunney et al. 2001), it is likely that this species was
successful in plantations because it had the ability to exploit abundant prey
outside its preferred prey range.
Large Predators
Plantations supported valuable food resources for large herpetofauna
but these were underutilized. The very low abundance of large herpetofauna
in plantations is not likely to be driven by prey availability alone because
pink-tongued skinks are cryptic and semi-arboreal and prefer dense ground
layers (Cogger, 1996) not available in young plantations. Livestock grazing is
known to negatively affect the abundance of reptiles of similar body size as
the ‘large’ lizards in this study (Kutt & Woinarski 2007, Brown et al. 2008) by
reducing the structural complexity of the understorey vegetation. The low
abundance of large lizards may also have been a more direct response to
plantation structure, because while food is abundant in plantations, retreat
sites are lacking in the plantation matrix itself, as hollow stumps, logs and
snags are only retained in habitat islands, and whilst Blue-tongued skinks will
tolerate open habitats, they require retreats to avoid predators. The
importance of refuges in maintaining ground fauna has demonstrated by
101
Chapter 4: Invertebrate resources and ground fauna
Webb and Shine (1998) who found that without suitable retreat sites, thermal
regimes forced snakes to switch habitats. Similarly the many studies that
advocate retained biological legacies like coarse woody debris a means to
increase faunal diversity (see Stevens 1997, Lindenmayer & Hobbs 2004 for
reviews), identify the importance of refuges in allowing species to persist in
managed habitats. A final explanation for low large lizard abundance in
plantations may be that large lizards are generally poorly represented in
systematic trapping surveys (Eyre et al. 1999, Borsboom et al. 2002) and so
may have been under-sampled by the trapping methods employed.
Whilst large rodents were significantly more abundant in native forests,
their preferred prey was more abundant in young plantations. However
invertebrate prey may not be the only dietary habitat selection cue for large
rodents, as other studies have identified that Bush rats (Rattus fuscipes) and
Swamp rats (Rattus lutreolus), the two rat species resident in plantations, use
invertebrate prey in summer to differing degrees (Cheal, 1987, Carron et al.
1990). While Bush rats are “selective” generalists that seasonally consume
fungi (Vernes & Dunn 2009), Swamp rats eat a large amount of plant
material (Watts & Braithwaite 1978, Cheal 1987). Thus for all the large
predators vegetation structure is likely play a strong role in contributing to
habitat choice.
Grazing
While grazing is likely to influence the quality of habitats at a local
scale in plantations, it is also has potential to be a landscape-level driver of
ground-level plant diversity and thus structural complexity. Livestock grazing
102
Chapter 4: Invertebrate resources and ground fauna
is common in young native plantations and is encouraged in this study as a
multi-use land strategy by plantation managers. While it is well documented
as negatively affecting specific ground fauna species by broadly reducing
habitat heterogeneity (e.g. Kutt & Woinarski 2007, Brown et al. 2008, Price et
al. 2010, Read & Cunningham 2010), its action at the landscape scale
(Fisher et al. 2004) means grazing is likely to influence regional species
pools. In this study while plantations have broad connection to closed native
woodlands, these woodlands have a long history of intermittent grazing at
low stocking density, suggesting that the negative effects of grazing may be
intensified by the position of plantations in the landscape mosaic.
We might expect this response to be strong for ground fauna of all sizes,
particularly small lizards and frogs, as dispersal ability in this faunal group is
often relatively limited (Brown et al. 2008). However in this study grazed
young plantations are more speciose than old growth native forests for every
taxon, suggesting that a complex interaction between grazing, habitat
simplification and dispersal is occurring. Prey availability has an important
role to play in this interaction as it may compensate for the lack of structural
diversity as a habitat selection cue, allowing small insectivores that aren’t as
explicitly reliant on retreats, to use young plantations.
Conclusions
This study has identified that young and old plantations support
significant food resources for small, medium and large epigaeic insectivores.
However medium and large-sized insectivores appeared to be responding to
habitat selection cues independent of prey availability, and patterns of habitat
103
Chapter 4: Invertebrate resources and ground fauna
use by these insectivores did not follow the abundance of preferred prey. If
species are foraging opportunistically, prey availability is likely to be an
important habitat selection cue for fauna using plantations, however in
plantations that are a thermally stressful habitat (Chapter 6), prey availability
appears to be less important in predicting where a species will be abundant
than extrinsic cues like retreat availability or substrate complexity. In addition
to prey availability, landscape composition and individual species habitat
requirements will need to be considered on a species-by-species basis in
order to predict the persistence of ground-fauna in plantations. Further
research needs to assess the residency of fauna in young plantations, and
particularly to identify whether management designed to enrich plantations
like retaining coarse woody debris acts as a habitat selection cue for species
of various body sizes, so increasing biodiversity across food chains. In my
study area this could have immediate implications for the management of
vulnerable species like Common Planigales, and should be addressed in
order to generate effective management for plantations currently being
established.
104
Chapter 5: Matrix quality and ground fauna
Chapter 5
Matrix quality and ground fauna diversity in young
plantations
Young native plantations in the landscape mosaic
Native plantations are increasing rapidly and within Australia, in the last
ten years, they have increased by 51% to an area of 0.99 million hectares,
representing 49% of the total plantation estate (Gavran 2013). Recent statistics
confirm that The Mid-North Coast forest region of New South Wales currently
supports 93% (86 296 ha) of the state’s hardwood plantation estate, and is one
of four areas in Australia with the fastest rate of increase in total plantation area
(mainly hardwoods) since 2005 (Gavran 2013). Thus young plantations (<10y.o.)
represent a significant and growing landscape feature in the region, and in
Australia as a whole. Despite the differences in species combination,
topography and proximity to native landscapes, all managed new plantations
have the potential to represent a cohesive landscape element because their
youth and the typically simple structure produced by standard establishment
procedures and subsequent management, creates a similar forest type where
plantation occur. Understanding how this expanding forest type is used by fauna
is particularly important in North-eastern New South Wales as this area is one of
the most biologically diverse regions of Australia (DEWHA 2009), and is home to
endemic and threatened species, as well as species at the margins of their
distributional ranges (Pressey et al. 1996).
105
Chapter 5: Matrix quality and ground fauna
One dominant paradigm of conservation in managed landscapes stems
from metapopulation and island biogeography theory (Ricketts 2001) and
consists of viewing the landscape as a fragmented series of habitat patches,
dominated by an extensive matrix habitat that has a strong influence on both
fauna and ecological processes (McIntyre & Hobbs 1999, Radford & Bennett
2007). This is extended by the landscape continuum model (see Lindenmayer &
Franklin 2002) which suggests fragment dwelling fauna can disperse in the
matrix along suitable food, shelter or climatic gradients. While applying these
models may be an appropriate approach to understanding the dynamics of
native forest patches within large-scale industrial exotic plantations, it may be a
less accurate way to predict diversity in young native plantations as it
necessarily brands them with the status of ‘fragment’. However, native
plantations in New South Wales are established on reforested pasture land,
often in broad connection to both existing forest types and cleared farmland.
Thus it may be misleading to view young native plantations as fragments. Given
their presence and connectance to the forest matrix, young plantations may be
better visualized as a skirt of compartmentalized blocks of simple forest (the
variegated landscape condition of McIntyre & Hobbs 1999), which border (and
may buffer) native forest from cleared land, and which may complement and
extend, rather than fragment, native forests.
The matrix and matrix quality
In the Macleay-Hastings management area of the North Coast Bioregion
the landscape mosaic is dominated by closed and open eucalypt forest and
106
Chapter 5: Matrix quality and ground fauna
woodland (Fig. 1), retained as part-forested agricultural land and a chain of
public reserves which link 25 national parks and 13 state forests between the
coast and the foothills of the Great Dividing Range (Pitt 2001). While young
plantations are present in the landscape, they are currently not extensive
enough to fragment native forests, but instead represent simplified habitat
patches containing small islands of complex structure (retained habitat features)
embedded in and adjacent to an extensive native forest matrix (Chapter 2).
Understanding how this forest matrix influences plantations is necessary to
understand the value of plantations for fauna, as the adjacency and quality of
the matrix can profoundly effect specific groups of fauna (Lindenmayer &
Franklin 2002, Loyn et al. 2007, Popescu & Hunter 2011).
The importance of the surrounding matrix in influencing plantation
biodiversity cannot be underestimated (Gascon et al. 1999, Lindenmayer &
Hobbs 2004, Umetsu & Pardini 2007; reviews by Brockerhoff et al. 2008,
Perfecto & Vandermeer 2010). As a matrix exotic plantations can ameliorate
species vulnerability to fragmentation in remnant native forest (e.g. Henle et al.
2004, Umetsu & Pardini 2007, Brockerhoff et al. 2008, Tomasevic & Estades
2008), facilitate dispersal between fragments (e.g. Marchesan & Carthew 2008,
Predevello & Viera 2010), and supplement species habitat or resources at a
landscape level (e.g. Pawson et al. 2008).
107
Chapter 5: Matrix quality and ground fauna
Fig 1. Two six-year-old hardwood plantations in the Mid North Coast NSW study area
showing typical connection to other landscape elements. A large retained habitat
feature is present in the right hand side photograph and both pictures show grazed
eucalypt woodland in broad connection to the edges of the plantation compartments.
At the stand scale exotic plantations may buffer fragments from adverse
environmental microclimates (e.g. Wright et al. 2010) and bias community
composition towards generalist species (Ewers & Didham 2006). However, while
a large body of work has looked at the role of native neighboring landscapes in
increasing diversity in native remnants (Munro et al. 2009, Archibald et al. 2011),
there is currently no published work investigating whether native matrices have
positive effects on fauna in native plantations.
Generally we might suppose that native plantations adjacent to the native
forest matrix will exhibit high diversity due to an influx of dispersers from source
populations, and that this diversity will be tempered internally by conditions
imposed by the plantation environment and externally by matrix quality. If
plantations are acting as a habitat sink, the age structure of populations within
plantations may be biased towards juveniles as plantations receive recruits from
native forests in close proximity (Jansen & Yoshimura 1998). Further to this, we
108
Chapter 5: Matrix quality and ground fauna
might expect that the simple environment of plantations would support more
generalist species than the surrounding matrix (Chapter 3), although this may
depend on matrix quality. Thus understanding matrix quality and its permeability
to fauna is important in predicting plantation diversity.
While matrix permeability may explain some of the high species diversity
in young plantations identified in this study for all fauna, and for generalist
species in particular (Chapter 3), it does not explain the lower abundance of
many species, particularly small mammals, in young plantations (Chapter4). If
low abundance is unrelated to food availability (Chapter 4), then it may be
related to the quality of the surrounding matrix (e.g. Perfecto & Vandenmeer
2002). In my study area the forest matrix adjacent to plantations is cattle-grazed.
Grazing has been demonstrated to negatively affect understorey complexity
(Yates et al. 2000) and associated ground fauna in several biomes (woodlands:
Bromham et al. 1999, James 2003, Driscoll 2004, Kutt & Woinarski 2007;
steppes: Beever & Brussard 2004; shrubland: Read & Cunningham 2010),
although responses to grazing can be highly species specific (Woinarski & Ash
2002, Fischer et al. 2004). Using standardized surveys this chapter evaluates
forest matrix use by herpetofuana and small mammals in comparison to
adjacent young plantations. I focus on ground fauna because they occur at low
abundance in plantations (Chapter 4), they are known to be negatively affected
by grazing, and their relatively low vagility means that landscapes are generally
less permeable for this faunal element, and so matrix quality may affect them
strongly. I test the theory that matrix quality is compromised by long-term
109
Chapter 5: Matrix quality and ground fauna
grazing. I hypothesize that if grazing has negatively affected the species pool
recruiting to young plantations then:
1) plantations should support a species richness similar to the forest matrix
regardless of the more complex simpler vegetation structure in
plantations
2) plantation population structures should be skewed towards a larger
number of juveniles if simplified habitat structure is generating a
population sink. If young plantations were a population sink young
dispersers moving into plantations from the forest matrix should bias the
population structure of plantation assemblages towards juveniles.
I test these hypotheses by comparing vegetation structure in grazed forest and
young plantations, the species richness and abundance of ground fauna in both
forest types and the population age structure of fauna in young plantations and
adjacent native forests.
Methods
Habitat Description
A general description of the study area and the young plantation
environment is presented in the study area section of Chapter 2. Sites within the
young plantation treatment were the same as those surveyed for fauna as
described in Chapter 3. In summary, young plantations at eight years old were
open-canopied, with a canopy height of approximately six metres, and a patchy,
grassy understorey dominated by Blady grass (Imperata cylindrica). A very
110
Chapter 5: Matrix quality and ground fauna
patchy shrub layer of the exotic Lantana camara was occasionally present.
Young plantations lacked logs and shrubby understorey. Establishment
procedures in young plantations included the retention of tree-bearing riparian
vegetation buffers, and aggregations of seed and habitat trees within the
plantation. Young plantations had been exposed to cattle grazing for two years
prior to the commencement of the study, and prior to plantation establishment,
the land had been grazed as pasture for at least 40 years. Forty percent of the
plantation edge abutted the native matrix forest, and was separated from it by a
four-metre-wide fire trail. Plantations were a three-species polycluture but all
sampling within them took place only in stands of Blackbutt (Eucalyptus pilularis).
The forest matrix adjacent to plantations in the study area was closed
woodland dominated by Blackbutt (Eucalyptus pilularis), and containing a
mixture of Tallowood (E. microcorys) and White mahogany (E. acmenoides),
typical of the region. A diverse subcanopy layer was present in places, and the
ground layer was patchily grassy and dominated by Blady (Imperata cylindrica)
and Basket (Lomandra longifolia) grasses. Fire had been excluded from all field
sites sampled in native forest for the eight years since plantation establishment,
as managers prioritized fire control in native forest due to the proximity of
plantations and the forest matrix (pers. comm., P. Levitske, SF Wauchope).
However fire scars on tree trunks and the abundance of stumps suggested that
forests had experienced at least one medium-intensity fire before 1996 when
plantations were planted. The forest matrix was grazed at low stocking density
111
Chapter 5: Matrix quality and ground fauna
for at least 40 years prior to the establishment of plantations (pers. comm., P.
Levitske).
Sites were selected to maximize distance apart within the plantations
(~1km), to standardize aspect, and to minimize distance between plantations
and the forest matrix. Each plantation site was paired with an adjacent matrix
site. All sites were situated 100 m from edges with cleared pasture as there is a
significant edge effect at the pasture-plantation boundary that persists for up to
50m (Chen et al. 1993, Wright et al. 2010). Five sites in each forest type were
sampled for fauna and vegetation structure. Sites were considered as true
replicates as other studies have shown that the small mammals sampled in this
research typically move less than 1km (Pires et al. 2002).
Vegetation structure
Vegetation structure was quantified in young plantations and adjacent
native forests by measuring characteristics from sixteen 20m2 quadrats along
four haphazardly placed transects spaced 150m apart, in each of five 200x600
sites. Vegetation variables were a subset of those measured in chapter 2 with
the potential to influence habitat use by ground fauna. Quadrats were spaced
70m apart along transects. Four quadrats from four transects in each of five
sites resulted in a total of 80 quadrats per forest type. All sampling was
conducted in October 2003. The vegetation characteristics measured were
known to influence habitat use in ground fauna (Table 1).
112
Chapter 5: Matrix quality and ground fauna
Table 1. Vegetation variables measured to quantify structural differences between
grazed native forest and young native plantation forest types on the Mid north coast of
NSW. Sampling effort was 80 quadrats from five replicate sites in forests and adjacent
young plantations. Paired t-tests identify significant differences between matrix and
young plantation for each vegetation variable.
Variable measured
Whole environment characters
number of trees
number of saplings
vertical complexity
crown height
canopy cover
midstorey height
Ground level characters
trunk cover
understorey height
shrub cover
grass cover
sedge cover
litter cover
litter depth
broadleaf cover
Definition
Trees are defined as any vegetation taller than 5m high
count
an estimate of how much vertical space between the ground and the
canopy is occupied by foliage
height to the canopy top but excluding emergent trees
amount of horizontal space covered by canopy foliage
height to the midstorey where present but excluding shrubs and subcanopy
Measurement
Method
count
count
categorical
McDonald et al. 1990
height
percentage
height
range finder
standardised photographs #
range finder
the amount of the quadrat coverd by tree truks of gretaer than 15cm diameter percentage
height of any vegetation up to 1.5m high
height
shruby growth forms only
percentage
percentage
sedeg were primarily Lomandra longifolia which formed patchy clumps
percentage
percentage
depth of leaves from the soil to the top of the leaf pack
depth
an estimate of the surface cover of fallen broad leaves from any species.
percentage
Broad leaves were ≥4cm in diameter.
rock cover
percentage
bare ground
percentage
log cover*
the total percentage of a quadrat covered by logs
percentage
log decomposition
a count of any holes/crevices in a log of >5cm long and 2cm wide
count
number of stumps
included to quantify the availability of vertical perches/basking points
count
presence of retreats
including sedge baskets, holes >3cm diameter in logs/ground/stumps
count
or log cracks >10mm wide and 5mm deep
*Logs were defined as any dead wood on the ground surface with diameter >5cm and length >15cm
#
Standardised photograhps of canopy cover classes are provided in McDonald et al. 1990.
ruler
visual estimate
visual estimate
visual estimate
visual estimate
ruler (cms)
visual estimate
visual estimate
visual estimate
visual estimate
modified from Fletcher (1977)
The percent cover of broad leaves and sedges were included as a specific
character of habitat for ground fauna as broader leaves can be specifically
attractive to thermophilic lizards (e.g. Valentine et al. 2007), and clumps of
sedges represented complex retreat sites for small species where the ground
was sparsely grassed. Litter depth was included because deep leaf litter packs
are necessary for daytime retreats and breeding in direct developing frogs such
as the Red-backed Toadlet (Pseudophyrne coriacea).
Fauna Trapping
Trapping included the use of standard procedures for sampling ground
fauna detailed in chapter three. Pitfall trapping was conducted over two years
between October 2002 - February 2003 and October 2003 - February 2004.
113
Chapter 5: Matrix quality and ground fauna
Live trapping was conducted from October 2003 - February 2004 in conjunction
with pitfall trapping. Pitfall trapping data from 2002-03 was a subset of data
analyzed in chapter 4, whilst live trapping data was independent of any other
trapping data presented in this thesis. Young and matrix forest types were
sampled by thirty live traps (Elliott traps, type “A”) laid in a 375 x 400 m (traps 50
m apart) grid in each site. Traps were opened between 16:00 and 08:00EST for
five consecutive nights, resulting in a trapping effort of 750 trap nights/forest
type. Traps were baited with a mixture of rolled oats, peanut butter, honey,
vanilla essence and salami. All animals captured were released at the trap site
after paint marking the bottoms of feet to identify recaptures. Recaptures were
excluded from data analyses.
Pitfall trapping arrays were established as per the methods described in
chapter three. Traps were initially opened for five day/nights, and re-opened at
four and eight weeks later for a second and third five day/night trapping period in
each site. Three arrays totaling 15 traps, for each of five sites, opened for 15
nights resulted in a total of 1125 trap nights per forest type. Traps were cleared
once per day in the mornings and, after measuring and individually paint
marking mammals all animals were released at the site of capture. Skinks were
uniquely identified by tail-regenerated tail and snout-vent length measurements,
and did not require marking. Detailed biometrics were recorded for mammals to
identify any recaptures between sampling periods within sites, and avoid
overestimating abundance. Although the time over which sites were trapped was
somewhat limited, it was considered adequate to estimate the distribution and
114
Chapter 5: Matrix quality and ground fauna
relative abundance and age structure of populations during the spring-summer
activity period for the most common herpetofaunal and small mammal species in
the study area, and encompassed the times in which juvenile herpetofauna and
mammals were recruiting into habitats
Data Analysis
Vegetation
A paired t-test was used to identify any differences in individual vegetation
characters between matrix and plantation forest types. Prior to analysis data
was averaged over quadrats to create site-level means, and for nominal
variables the modal value was applied.
Fauna
Fauna were classified as either generalist or specialist on the basis of
strong preferences for diet or specific habitat features (defined in Chapter 4).
While this is a coarse predictor of expected habitat use, it can provide some
indication of the negative response of a species to habitat alteration, as many
studies identify that abundance of generalists increases in modified landscapes
(e.g. Devictor et al. 2008). Individuals were allocated into either adult or juvenile
age classes based on morphometrics. Adult mammals were identified by pes
length and head width as per published records, or by reproductive condition.
Adult reptiles were defined as those having a snout-vent length of at least four
fifths of the mean snouth-vent length for each species (using an average of all
115
Chapter 5: Matrix quality and ground fauna
trapping records for that species throughout the study). This means that the
juvenile category included some sub-adults, which for the purposes of this
chapter are discussed as juvenile. Herpetofauna were analyzed as a group
because given the small body sizes and cryptic habitats of many of the snake
and lizard species trapped, their dispersal ability was assumed to approximate
that of frogs. Mammals were analyzed separately. Juvenile and adult captures
were pooled for all analyses except those focused specifically on age effects..
Paired samples t-tests were used to compare the abundance and species
richness of small mammals and herpetofauna among forest types using SPSS
v21.0 (SPSS 2012). Before analysis data were pooled to site level and log (x+1)
transformed, to satisfy assumptions and homogenize variance among forest
types. Two-way Analysis of Variance (ANOVA) was used to test whether the
abundance of species with specific habitat preferences differed between forest
types, and repeated to test whether adults and juveniles were significantly more
abundant in plantations and matrix habitats. Bonferroni correction was applied to
all estimates of significance to reduce error rates associated with multiple
analyses.
Results
Vegetation structure
Vegetation structure differed significantly between young plantations and
adjacent native forests. Native forests had greater leaf litter cover with deep leaf
pack, a taller understorey, more saplings and shrubs, and higher log cover with
logs that contained retreats. These were almost completely lacking in
116
Chapter 5: Matrix quality and ground fauna
plantations. Whilst plantations contained higher tree density, the percentage of a
quadrat covered by tree trunks was higher in forests due to greater tree girth.
Plantations had a greater cover of rocks and bare ground than forests, but both
habitats had similar grass cover. Whilst broad leaf cover did not differ between
forests and plantations in forests leaves were native, whilst in plantations they
originated primarily from exotic Lantana camara (pers obs).
Table 2. Paired t-tests for differences between grazed native forest and young
plantation vegetation variables measured from 80 quadrats in five replicate sites on the
Mid North Coast of NSW. Significant values are denoted in bold.
Mean
Variable measured
Matrix
Plantation
Whole environment characters
number of trees
6.267
13.475
0.775
number of saplings
8.636
vertical complexity
0.200
1.013
crown height
31.592
10.000
canopy cover
43.333
17.713
midstorey height
13.962
0.024
Ground level characters
trunk cover
3.933
1.763
understorey height
39.844
4.938
shrub cover
2.615
15.187
grass cover
66.572
94.200
sedge cover
0.894
0.000
litter cover
51.244
5.750
litter depth
5.113
2.264
broadleaf cover
21.125
0.525
rock cover
0.350
1.138
bare ground
0.975
15.188
log cover
8.950
0.013
log decomposition
3.011
0.213
number of stumps
0.789
0.000
presence of retreats
0.942
0.000
df
t
p
4 -11.088
4
4.505
4
1.137
4 21.913
4 11.186
5.349
>0.001
0.011
0.319
>0.001
0.006
>0.001
4 2.908
4 4.177
4 -3.993
4 -2.159
4 22.011
4 -4.124
4 3.622
4 2.238
4 -7.188
4 -1.297
4 7.024
4 12.033
4 4.105
4 25.924
0.044
0.014
0.022
0.097
>0.001
0.013
0.022
0.089
0.002
0.264
0.002
>0.001
0.015
>0.001
Fauna
In total 475 individuals from 26 species, from seven mammal, four frog
and 15 lizard species were captured (Appendix 3). Young plantations and
adjacent native forests each supported 20 species. Woodland-associated fauna
117
Chapter 5: Matrix quality and ground fauna
comprised 35.2% of capture, whilst forest and generalist species comprised 13.3
and 51.4% respectively. Despite large differences in vegetation structure
between the forest matrix and young plantations, mammal and herpetofaunal
abundance and species richness was similar in both forest types (Table 3).
Table 3. Summaries for paired t-tests examining differences in ground faunal species
richness and abundance from native eucalypt woodland and adjacent native plantations
on the Mid north coast of NSW. Sampling effort was 750/1125 trap nights for live/pitfall
trapping from five replicate sites.
Variable measured
mammal abundance
mammal richness
herpetofaunal abundance
herpetofaunal richness
Mean
Matrix Plantation
46.6
27
9.8
11.6
8.8
6.2
1.6
2.6
SD
41.789
17.021
4.037
1.732
df
1.049
-0.236
1.44
-1.291
t
4
4
4
4
p
0.353
0.825
0.223
0.266
However forest mammals and herpetofauna were significantly less abundant in
young plantations than matrix forests (herp: F2,24 = 9.200 p = 0.002, mammals:
F2,15 = 12.485 p = 0.001, Fig. 1a). House mice (Mus musculus), Swamp Rats
(Rattus lutreolus), Common Dunnarts (Sminthopsis murina), Jacky Dragons
(Amphibolurus muricatus) and Robust Striped Skinks (Ctenotus robustus)
replaced Bush rats (Rattus fuscipes), Red-tailed Calyptotis (Calyptotis
ruficaudata) and Red–backed toadlets (Pseudophryne coriacea) (Appendix 3).
Adult mammals and herpetofuana were significantly more abundant than
juveniles, but the abundance of juveniles did not change in matrix forests and
plantations (Table 3, Fig. 1b).
118
Chapter 5: Matrix quality and ground fauna
Fig.2 Mean abundance of (A) forest, woodland and generalist species and (B) of adults
and juvenile mammals and herpetofauna sampled from native forest matrix and
adjacent young plantation forest types from five replicates sites on the Mid North Coast
of NSW. Error bars are 95%CI.
119
Chapter 5: Matrix quality and ground fauna
Discussion
In this study in coastal New South Wales grazed native forests adjoining
grazed young eucalyptus plantations supported equally rich and abundant
populations of ground fauna. Whilst generalist species dominated plantations,
the species richness of ground fauna identified in this study approximated that of
old growth native forests in the region (Chapter 3). The first hypothesis posited
in this chapter suggested that equivalent species richness in the matrix and
young plantations may indicate poor quality of the matrix habitat. However, the
high species richness of ground fauna in in both forest types and the presence
of abundant forest-associated species, identifies that both that young plantations
and grazed native forest matrices act as habitat in the study area.
Matrix quality
The effects of grazing on plantations
Pastures are known to rarely support reptiles (Driscoll 2004, Kavanagh et
al. 2005, Kanowski et al. 2006) or small mammals (Downes et al. 1997), and in
the study area are documented as lacking small mammals (Law et al. 2002) .
Thus, if pastures provide an effective barrier for small mammals, faunal
assemblages within plantations adjacent to pastures and forests are likely to
originate from immigration through the forest matrix. However, in this study
plantation herpetofaunal assemblages were not subsets of the forest
assemblage, but included the heliothermic Striped Skinks (Ctenotus robustus)
and Jacky Dragons (Amphibolurus muricatus), which were not trapped in the
120
Chapter 5: Matrix quality and ground fauna
forest matrix. Whilst this result may arise from the snapshot nature of sampling
in this study, it could also suggest that grazing in the forest matrix can increase
the permeability of the matrix for woodland species by creating open spaces in
the understorey (e.g. Yates et al. 2000). Without a direct comparison of faunal
diversity in pastures, plantations and forests, my explanation for high
abundances of woodland species in plantations but not matrix habitats, must
remain hypothetical.
The effect of grazing in the forest matrix on mammals is less clear.
Chapters three and four of this thesis consistently identified young plantations as
supporting < 50% of the mammal abundance of undisturbed forests, yet in this
study plantation and matrix mammal abundance is similar. This study records
that the matrix supports the lowest mammal abundance recorded in three years
of trapping. Whether such low abundance results from reduced matrix quality or
is related to decreasing rainfall during the course of this study is uncertain. Even
if matrix quality was unaffected by grazing, this may not have resulted in species
gains in adjacent plantations, as young plantations simply did not embody
enough forest-like features to be attractive to other forest mammal species
known from the regional pool. Combined, these results indicate that mammal
and herpetofaunal responses to habitat simplification through grazing can vary
considerably. If a cessation of grazing in the matrix resulted in an increase in the
structural heterogeneity of forests (e.g. James 2003) this may decrease matrix
permeability for lizards by physically obstructing dispersal (Prevedello et al.
2010), or by altering the availability of thermal resources which may have knock-
121
Chapter 5: Matrix quality and ground fauna
on negative consequences for reptile fauna. However, if the lack of transfer of
mammal species between forests and young plantations is typical for mammals,
in woodland environments whilst a cessation of grazing in the matrix might
benefit local diversity, it would be unlikely to affect plantation diversity. Clarifying
the role of grazing and its interaction with species transfer between forests and
plantations will require further study, and may benefit from a case-by-case basis
as has been stressed previously by other authors (Fischer et al. 2004, Felton et
al. 2010).
Age structure
The age structure of mammal and reptile populations in plantations were
not skewed towards juveniles relative to those in the native forest matrix,
suggesting that species abundance in young plantations was unlikely to have
been be maintained by recruitment. However, the alternative hypothesis that
reptiles reproduce well in plantations but persist in a strongly adult-biased
population due to a loss of young through predation or emigration is equally
plausible, although to support this hypothesis, trapping would have been
expected to reflect higher numbers of juveniles. Both ideas hinge on the
effectiveness of sampling for juveniles in this study. While sampling took place
at the time when new recruits should be evident in populations, relatively poor
capture rates for juveniles of both faunal groups suggests either that standard
sampling methods for ground fauna are biased towards adults, or that naive
recruits really were simply experiencing high predation pressure in young
122
Chapter 5: Matrix quality and ground fauna
plantations where the availability of retreats was much lower. A targeted study
focusing on the recruitment of reptiles through the plantation-matrix boundary
and particularly on the persistence of reptiles in young plantations after
recruitment is necessary to clarify what drives such age-biases.
Conclusions
The grazed forest matrix adjacent to young native plantations in this study
had the potential to represent different habitat quality for herpetofauna and
mammals. In this study the grazed native forest matrix had some potential to
influence the diversity of herpetofauna in young native plantations adjacent to,
and connected with, the matrix by acting as a source of recruits and a
permeable conduit for reptiles (e.g. Kupfer et al. 2006). The quality of this matrix
for ground mammals was more ambiguous. In contrast to reptiles, while the
abundances of mammals were equivalent in the matrix and young plantations,
they were significantly lower than those supported by ungrazed native forests
sampled in other parts of the study area (Chapters 3 + 4). Until the role of
grazing in the forest matrix and its effect on the recruitment of ground fauna into
plantations is understood, managers should consider situating new plantations
in the landscape mosaic in proximity to grazed and ungrazed forests. Where
management targets vulnerable species in the region like the Common
Planigale (Planigale mauclata), which uses plantations and ungrazed native
forests (Chapter 3) but is absent from grazed forests (this chapter), grazed
matrices may be less valuable as a source of recruits. Future research efforts
123
Chapter 5: Matrix quality and ground fauna
that focus on understanding immigration and residency in plantation fauna and
on their relationship with surrounding agricultural matrices, will clarify the role of
native matrices in contributing native plantation biodiversity.
124
Chapter 6: Lizard habitat choice
Chapter Six
The roles of structural and thermal factors in
determining habitat choice by lizards in young
plantations
Introduction
Understanding how habitat choice affects local species distribution
and abundance is one of the factors necessary for the development of
effective management plans for biodiversity conservation. However,
knowledge of the ecological requirements and habitat relationships of many
species, especially reptiles (Michael et al. 2010), is often poor. Reptiles are in
decline globally (Gibbons et al. 2000), and as poor dispersers they are
vulnerable to landscape scale changes (Gardner et al. 2007b, Brown et al.
2008) which change vegetation structure and thus thermal habitats. The
availability of appropriate microhabitats with suitable thermal ranges has
been long accepted as an important habitat selection cue for reptiles (e.g.
Grant & Dunham 1988), because available temperatures constrain activity
(Magnuson et al. 1979, Tracy & Christian 1986, Dunham et al. 1989, Díaz
1997). Whilst a growing body of research attempts to identify how reptile
habitat selection changes in human-modified landscapes (e.g. Row & BlouinDemers 2006, Todd & Andrews 2008, Wanger et al. 2009) very few studies
have examined the thermal properties of plantation habitats and their impacts
on reptiles (e.g. Becker et al. 2007, Mott et al. 2010).
125
Chapter 6: Lizard habitat choice
Thermal environment and habitat choice
An animal’s thermal environment is the result of complex interactions
between many physical characteristics of a specific location, which include
the amount and direction of solar radiation, air and substrate temperatures,
and convective characteristics. Because of the dominant influence of solar
radiation on diurnal microclimates, complex vegetation can markedly
influence the thermal potential of a given habitat by limiting the amount of
direct sunlight and providing a greater range of convective and radiative
conditions than occur in more open habitats. The importance of specific
microclimates as habitat selection cues is well recognized for both diurnal
and nocturnal ectotherms (e.g. fish – Wehrly et al. 2003, Ward et al. 2010;
invertebrates –Pereboom and Beismeijer 2003, Ahnesjö & Forsman 2006;
herpetofauna – Cowles & Bogert 1944, Tracy & Christian 1986, Adolph
1990, Webb & Shine 1998, Sabo 2003, Goldsborough et al. 2006, Row &
Blouin-Demers 2006, Bancroft et al. 2008, Hoare et al. 2009). In addition to
the thermal influence of daytime light levels on microclimate, light may also
affect habitat choice through its effects on visual systems and associated
communication and predator avoidance (Carrascal et al. 2001, Leal &
Fleishman 2004).
Previous studies investigating the roles of microclimate and structure on
animal habitat selection have inferred thermal environments from light
penetration through tree canopies (Pringle et al. 2003, Langkilde et al. 2003)
or have used qualitative measures of structural complexity (Schultz 1998,
Skelly et al. 1999, Halverson et al. 2003, Pineda & Halffter 2004). Such
measurements are biased to visible wavelengths, and consequently ignore
126
Chapter 6: Lizard habitat choice
ultraviolet and infrared components of the light spectrum. However, nonvisible wavelengths of light are known to influence habitat selection in birds,
mammals and reptiles (Walsberg et al. 1997, Carrascal et al. 2001, Huey
1991, Christian et al. 1996), and are important for foraging and social
behaviours in many birds, reptiles and amphibians (e.g. Fleishman et al.
1997, Honkavaara et al. 2002). Infrared wavelengths are particularly
important for behavioural thermoregulation in heliothermic reptiles (Christian
et al. 1996, Belliure & Carrascal 2002) as this part of solar radiation
constitutes up to half of the energy received at the ground during the day
(Brown & Gillespie 1995, Kotzen 2003). Because of the highly variable
nature of vegetation in modifying particular wavelengths of sunlight and so
changing the thermal and photic characteristics of a particular microhabitat
(e.g. Yang et al. 1999, Dölle & Schmidt 2009), it is very difficult to predict the
consequences of vegetation restructuring on biodiversity. Such predictions
require an understanding of how resident animal species respond to changes
in irradiance and habitat complexity as well as how changes to vegetation
structure affect these interactions.
Thermal physiology of reptiles
Temperature is known to strongly affect physiological processes
associated with energy gain and expenditure (e.g. Harlow et al. 1976, Huey
1982, Alexander et al. 2001, Pafilis et al. 2007). While moderate to high body
temperatures can maximize performance (Huey & Kingsolver 1989) including
behaviours such as predatory efficiency (Díaz 1995) and rates of digestive
processes (e.g. McConnachie & Alexander 2004), the actual body
temperature required for optimization of particular functions varies markedly
127
Chapter 6: Lizard habitat choice
between species, and often reflects their natal environment (e.g. Bilcke et al.
2006, Aubret & Shine 2010). Consequently, the extent to which animals can
exploit new environments depends on their behavioural capacity to attain
optimal body temperatures in the new habitat, or their potential to adjust
thermal optima for physiological functions through acclimation (Van Damme
et al. 1990). Many ectotherms behaviourally thermoregulate to attain a limited
range of preferred body temperature ranges. Maintaining preferred
temperatures increases fitness by optimizing growth (Sinervo & Adolph
1994), performance (e.g. Huey & Kingsolver 1993, Downes & Shine 1998,
Pitt 1999) and reproduction (Shine 2005). By contrast, habitat generalists that
occupy a broader range of thermal environments may trade off performance
optima at particular temperatures, for lower performance over a broader
range of temperatures.
Constraints of plantations environments on lizards
Whilst recognition of the conservation value of native plantations for
fauna is increasing (Brockerhoff et al. 2008) most studies have examined the
structural complexity of vegetation (see Brockerhoff et al. 2008 and
Hartmann et al. 2010 for reviews), plantation size and landscape context
(Kavanagh et al. 2001) as drivers of change in diversity between hardwood
plantations and native forests. The role of thermal and light environments and
their influence on habitat choice in native plantations remains largely
unexplored. Monoculture tree plantations provide an excellent opportunity to
address these questions about the role of thermal environments as their
uniformity in tree species, size and distribution can generate specific thermal
128
Chapter 6: Lizard habitat choice
microhabitats, and these microhabitats change in predictable directions as
plantations age. Given that there are recognized differences in the
attractiveness of plantations of different ages to fauna (e.g. Borsboom et al.
2002, Hobbs et al. 2003) and plantation management goals often include
increasing faunal diversity, differentiating thermal from structural habitat cues
may provide a key to understanding plantation faunal diversity.
In artificial environments such as managed plantations, where planting
structure facilitates early canopy closure, the relationship between light, heat
and vegetation structure is not always linear. As a consequence, high canopy
density, low light and cool environmental temperatures can be linked to low,
rather than high, understorey structural complexity (Chapter 2). This has
ramifications for biodiversity within plantations if thermal and structural
habitat selection cues differ in importance among animal species. The extent
of this effect will depend on the behavioural and physiological flexibility of
each species, which ultimately determines whether a species can accept
thermal conditions outside of the preferred temperature range (see Heatwole
1977, Huey 1982, Heatwole & Taylor 1987, Blouin-Demers & Nadeau 2005
and Vickers et al. 2011 for more discussion).
This thesis has identified that native tree plantations on the Mid North
Coast of New South Wales had more open canopies, more simply structured
sub-canopy vegetation, received higher insolation at the ground, and attained
higher and more variable diurnal environmental temperatures than native
forests (Chapter 2). Lizard assemblages responded to these shifts in
available microhabitat. The hot, simple plantation environments supported
129
Chapter 6: Lizard habitat choice
distinct assemblages dominated by small-bodied open forest-woodland and
generalist species and heliotherms (Chapter 3), a shift previously identified
between plantation and forest environments for tropical reptiles in exotic
plantations (Gardner et al. 2007a) and temperate reptiles in native
plantations (Ryan et al. 2002, Kanowski et al. 2006). Young native
plantations conspicuously lacked forest specialist herpetofauna, and largebodied species were rare despite an abundance of palatable invertebrate
prey (Chapter 5).
This chapter aimed to identify whether forest specialist lizards were
absent from young native plantations due to physiological constraints
associated with the thermal environment in young plantations, or due to
behavioural constraints driven by preferences for specific structural attributes
of the environment unavailable in plantations. To apply these ideas the
physiological consequences of habitat choice on forest specialist, generalist
and plantation-associated lizards were examined experimentally. Appetite
and gut passage rates and habitat selection preferences were compared
between species at temperatures common to young plantations at the peak
of lizard activity in summer.
I hypothesized that:
1. generalist species occurring in both plantations and forests would
have a broader preferred temperature range than habitat specialists
2. because coadaptation amongst traits that strongly affect fitness
should be favoured (Mayr, 1963) specialist species would choose habitat
based on a preference for substrate type, and would thermoregulate narrowly
130
Chapter 6: Lizard habitat choice
3. because preferred temperature maximizes enzyme function (Harlow
et al. 1976, Hochacha & Somero 1984), gut passage rate would be slower in
specialist species in temperatures common to habitats outside their own,
where preferred temperatures would be harder for lizards to achieve.
Methods
Study System
Due to the influence of phylogeny on preferred body temperature
(Garland et al. 1991), I restricted species for comparisons to diurnally active
skinks from the sub-family Lygosominae. All species were morphologically
similar, but differed somewhat in body mass and limb:body ratio, and all were
carnivorous, eating a typical scincid diet of spiders, coleopterans, insect
larvae, gastropods and ants, lizards (Wilson & Knowles 1988). The species
used in experiments in this chapter were those identified previously as being
habitat restricted (Chapter 3). They included three diurnal, surface-active
species the plantation-restricted Adrasteia amicula, the old growth native
specialist Eulamprus murrayi and the wide-ranging generalist Lampropholis
guichenoti ; and two cryptozoic species, the forest-associated Calyptotis
ruficaudata, and the woodland-associated Lerista muelleri. The species in
order of size were Eulamprus murrayi (SVL: 87mm, mass: 15.70 ± 3.12g),
Lerista muelleri (SVL: 56mm, mass: 1.66 ± 0.40g), Calyptotis ruficaudata
(SVL: 42mm, mass: 1.16 ± 0.30g), Lampropholis guichenoti (SVL: 35mm,
mass: 0.88 ± 0.24g) and Adrasteia amicula (SVL: 15 mm, mass: 0.52 ±
0.26g). All of these species are heliothermic (use the sun as a heat source),
131
Chapter 6: Lizard habitat choice
but E. murrayi is a sedentary a posturing heliotherm and regulates body
temperature by altering the preferred angle of the body to the sun
(Hutchinson 1993). Whilst C. ruficaudata and L. muelleri are cryptozoic
species, they were included in this study because retreat choice in cryptozoic
species is influenced by thermal characteristics (e.g. Shah et al. 2004) and
preliminary field observations identified surface basking for both species. L.
guichenoti and A. amicula are shuttling heliotherms, and control their body
temperature almost entirely by actively moving between sun and shade.
Habitat choice enclosures
To separate behavioural preferences based on structure from those of
thermal microclimate, four enclosures with particle-board walls were built in
the central part of the study area near Wauchope on the Mid North Coast of
New South Wales. These were placed in an open paddock in cleared
farmland that was unshaded by trees. Enclosures were built to expose lizards
to a series of specific thermal and structural microenvironments. They offered
a choice of simple and complex substrates, built to mimic those available in
plantations or native forests, along a gradient of solar irradiance. Three large
enclosures (7.5 x 3 m, Fig 1a), partitioned internally into five 1.5 x 1.5 x 1m
compartments, and connected to the two adjacent by 15 x 15cm openings
(Figure 1a). Enclosures were oriented along the solar path to minimize
internal shading by the partition walls, and while a small amount of shading
occurred, this area was consistent among treatments within each box. A
solar energy gradient was generated by roofing each compartment with
shade cloth which allowed 96%, 70%, 50% and 10% of incident sunlight
respectively (Fig 1b), based on readings from a calibrated pyranometer
132
Chapter 6: Lizard habitat choice
(model LP 02L, Campbell Scientific). Monofilament bird netting allowing 100%
radiant energy penetration was placed over the unshaded treatment, to
prevent predation and standardize disturbance levels when checking the
position of animals. A fourth and much smaller enclosure (2.8 x 0.9m) was
divided into ten compartments (56 x 45 x 50cm) to examine habitat choice in
Adrasteia amicula because of its much smaller adult size (0.5g). Substrate
types were the same in all enclosures,
One of each pair of compartments at each level of irradiance was
randomly assigned a substrate, either ‘complex’: representing the complex
ground layer common to forests and containing a complete covering of forest
leaf litter, five logs with a minimum diameter of 15cm and a log pile of three
additional logs, or ‘simple’: a ground layer common to plantations mimicked
using six vertically positioned bunches of dry native grass collected in the
study area (Fig 1c), built to approximate the tussocks of Blady grass
(Imperata cylindrica) common to plantations in the study area. Up to 60% of
the substrate floor in the simple treatment was bare, in accordance with the
conditions common to plantations in the study area, but in both choice boxes
10% of the grass or logs were placed against the shadowed wall of the box,
to allow lizard a choice of sheltered temperature ranges. Prior to applying
substrates, enclosures were floored with weed matting to prevent animals
escaping and were covered with a layer of mixed river sand and local soil
~8cm deep. Air temperatures did not vary significantly between
compartments of the enclosure as a result of the access ports between
compartments. These ports were large enough to permit lizards to readily
view and assess adjacent compartments.
133
Chapter 6: Lizard habitat choice
A
B
C
S
S
C
C
S
C
C
S
S
100
90
50
30
4
% Radiant energy penetration
C
Fig. 1. Choice enclosures in situ on the Mid North Coast of NSW. A. Large
enclosures; B. Diagramattic representation of the relative amount of ambient
radiant energy and substrate present in each compartment, (c = complex, s =
simple). C. An example of the complex (left) and simple (right) substrates lizards
could select.
Operative environmental temperatures (Tenv; Bakken 1992) within
compartments were measured using iButton data loggers (model DS1921L,
Dallas Semiconductors). These were plastic wrapped and painted with
neutral-coloured paint (following Walsberg & Weathers 1986) to closely
match lizard coloration. Data loggers were placed in the hottest (full sun) and
coolest (full shade) microenvironments in both substrate treatments in each
134
Chapter 6: Lizard habitat choice
compartment of all enclosures. Prior to introduction of lizards, preliminary
tests confirmed that small and large boxes and complex and simple
substrates sharing the same shade treatment did not differ in levels of
insolation received or in Tenv through the diel cycle. To quantify the
relationship between insolation and body temperatures (Tb) in experimental
enclosures, insolation readings were collected hourly from each box each
day of sampling using a pyranometer (LP 02L, Campbell Scientific) that
measured a combination of ultraviolet, near-infrared and incident
wavelengths of light.
Sampling of young plantation thermal environments was conducted in
conjunction with preferred temperature experiments to provide an estimate of
available temperature in young plantations, to compare with experimentally
determined preferred temperature ranges. Environmental temperature (Thab)
in young plantations was sampled in shaded and unshaded sites using
iButton data loggers (model DS1921L, Dallas Semiconductors). Preparation,
replication and placement of these data loggers followed methods described
in chapter two. Thab measurements indicated the range of temperatures
available to lizards in young plantations at the appropriate spatial scale. Field
Thab was recorded from September 2002 – March 2003 (spring - summer),
corresponding to the period of sampling in the field enclosures, and maximal
activity in lizards. To verify that environmental temperatures (Tenv) available
in the enclosures fell within the range of those available in the wild, iButtons
were also placed in sun and shade microhabitats within enclosures at each
level of shading.
135
Chapter 6: Lizard habitat choice
Scincid lizards were hand captured by active searching and pitfall
trapping in the forest types described in chapter two during October and
November 2002 and January 2003. A minimum of fifteen individuals of each
species were sampled (Table 1). Lizards were introduced singly into choice
boxes within two hours of capture and allowed to familiarize themselves with
the enclosure for 24 hours. Several mealworms (Tenebrionid sp.) and eight
commercially available crickets (Gryllus sp.) of appropriate size were
provided ad libitum in each box as was water via a dish and twice-daily
spraying of the enclosure walls. All species of lizards were observed using
these resources during the period of familiarization. Naturally occurring prey
(ants, moths, flies, beetles) also entered enclosures and were eaten by
lizards.
Sampling involved scoring each individual for position, substrate type
and behaviour every 30 minutes between 0800h and 1700h, times
associated with most daily activity. Specific behaviours were recorded, and
were subsequently divided and then pooled into ‘active’ and ‘inactive’
categories for analysis. To score ‘active’ a lizard was basking, foraging,
fleeing, exploring or retreated under shelter but moving and alert. To score
‘inactive’ a lizard was buried in the substrate, or retreated under shelter but
not alert. Cryptozoic species were considered active even when retreated
under logs, but were scored as inactive when eyelids were closed or when
they were buried in the substrate. Cryptozoic species were located by tracks
and pinpointed by uncovering only enough of a retreat to allow sighting of an
individual, after a pilot study verified that this level of disturbance did not
cause them to change position. In addition, lizards were captured every 1.5
136
Chapter 6: Lizard habitat choice
hours, and external groin temperature (Tb) was recorded using a calibrated
quick reading Schultheis thermometer within five seconds of capture, as an
infrared thermometer could not differentiate the small size of the lizards
against the substrate to allow measurement. Groin temperature was
measured by pressing the thermometer bulb against the junction of the
hindlimb and abdomen. This method was previously established to closely
approximate cloacal temperature and to be much quicker and less stressful
for scincids than repeatedly sampling cloacally. Body temperatures were not
recorded for any lizard that fled for more than 15cm from the point of first
observation, to avoid any temperature bias associated with sprinting or
forced change of microhabitat. After sampling all lizards were returned to
point of capture within the enclosure, and substrate temperature at the site of
capture was recorded. All experimental trials were conducted on sunny days.
All lizards were returned to their original capture site within 24 hours of
cessation of the enclosure experiments, and each lizard was tested only
once.
Data Analysis
To identify how insolation affected microclimate throughout the day
linear mixed-effects repeated measures models were used. This type of
model better handles correlated data and unequal variances than general
linear models associated with analysis of variance, by accounting for residual
errors which are correlated within each subject, but independent across
subjects (see Verbeke & Molenbergs 2000 and Demidenko 2004 for more
discussion of these models). To identify differences in Tenv between shading
levels, time and position in the gradient (fixed factors) and data logger
137
Chapter 6: Lizard habitat choice
(repeated factor) were analyzed using log transformed data. This analysis
was repeated using the same fixed factors for insolation data but replacing
data logger with day as the repeated factor. To identify any change in mean
Tb within time of day a third mixed model replacing day with individual identity
was analyzed using log transformed data, separately for each lizard species,
as no transformation could normalize the data for a species-combined data
set. Because this test identified a consistent diel rhythm in mean Tb typical of
diurnal species (Heatwole 1987), a two-way analysis of variance (ANOVA)
testing for differences in Tb between species included time as a co-variate.
All test assumptions were satisfied before analysis. For graphical purposes
the preferred temperature range was defined as the central 68% of Tb
recorded in enclosures. This range is considered to represent the typical Tb
that a species prefers during activity (Huey 1982). Substrate preferences
were described qualitatively as choice was highly skewed with all species
preferring complex substrates more than 90% of the time, and three of the
five species only using complex substrates. For all models tested an alpha
level of p< 0.05 was considered significant and Type III sums of squares
were used. Analyses were performed using SPSS version 16 (SPSS 2007).
Results
The insolation received at the ground varied with time of day and level
of shading (shade*time - F40,151.1 = 6.475, p < 0.001) as did the associated
Tenv (shade*time - F60,13543.0 = 116.666, p < 0.001). Whilst shade treatments 0
and 10 consistently received higher insolation throughout the day (Fig. 2a),
they were only hotter in the morning, with Tenv equalized across all levels of
shading after 1100h EST (Fig. 2b). Despite these fluctuations lizards
138
Chapter 6: Lizard habitat choice
thermoregulated carefully throughout the day. After heating to their preferred
temperatures between 0800h and 0900h EST all species maintained mean
Tb of 29 – 30 ± 1.5 - 2.50C (Table 1, Fig. 2c) apart from the forest specialist
Eulamprus murrayi which maintained a significantly cooler Tb of 24 ± 3.50C
throughout the day (F4,376 = 52.055, p<0.001; Fig. 2c).
Whilst Tb fluctuated with time of day for all species it was independent
of location alone (Table 2), and each species used location in the gradient
differently according to their behavioural mode. Lampropholis guichenoti and
Adrasteia amicula were the most active species while the cryptozoic
woodland and forest-associated Calyptotis ruficaudata were relatively
inactive, and the forest-specialist Eulamprus murrayi fell in between these
groups.
Table 1. Body temperatures and habitat associations of target species in
experimental choice boxes on the Mid North Coast of New South Wales. Mean temp
is pooled over positions in enclosures and excludes the first temperature recording
between 8 and 9am where lizards were heating to preferred temperature. Range
encompasses the central 68% of the body temperatures measured.
Species
L. guichenoti
A. amicula
L. mulleri
C. ruficaudata
E. murrayi
n
23
19
15
17
18
Mean
Temp
29.71
29.96
30.49
30.78
24.41
SD
2.54
1.73
2.01
1.6
3.48
Occurrence
all habitats
young plantation
forests, old plantation
forests, old plantation
old growth forest
Behavioural
Mode
shuttling heliotherm
shuttling heliotherm
cryptozoic
cryptozoic
posturing heliotherm
Two distinct activity patterns emerged with the shuttling heliotherms
Lampropholis guichenoti and Adrasteia amicula being active throughout the
day, and using the less shaded end of the gradient preferentially for the first
three hours of measurement. This behaviour occurred even though
temperatures in the gradient at locations 0 and 10% shade exceeded mean
preferred temperature range for all species between 0800 and 0110h (Fig.
139
Chapter 6: Lizard habitat choice
2b). In the afternoons this pattern switched and A. amicula became less
active and was associated with locations having the least irradiance. The
more sedentary woodland Lerista muelleri and forest–associated Eulamprus
murrayi and Calyptotis ruficaudata were consistently recorded from the more
shaded end of the gradient, but differed in activity patterns. Both L. muelleri
and C. ruficaudata were unimodal in activity pattern and were active until
11am, and whilst they were both inactive for the latter part of the day, C.
ruficaudata used all positions between 50-96% shade, while L. muelleri
occupied retreats primarily in 96% shade. E. murrayi fell between these two
groups and while it showed sporadic activity throughout the day, it was
restricted almost exclusively to 96% shade to maintain its low preferred
temperature.
All lizards strongly preferred complex to simple substrates in the field
enclosures (percentage of use of complex substrate for each species:
guichenoti = 95%, amicula = 92%, muelleri = 100 %, ruficaudata = 97%
murrayi = 99% - from 1077 observations of substrate choice in total),
however, whilst L. guichenoti and A. amicula the two species using
plantations were expected use simple substrates, the forest-associated C.
ruficaudata also tolerated simple substrates whilst inactive.
Table 2. Results of mixed model analyses for change in body temperature with
position in experimental choice boxes. TOD = time of day, Loc = position in the
gradient corresponding to level of insolation. Significant values are in bold.
Species
L. guichenoti
Factor
Loc*TOD
df
19,57.0
F
2.543
p
0.003
A. amicula
Loc*TOD
10,30.4
1.819
0.049
L. mulleri
Loc*TOD
5,14.3
7.288
0.001
C. ruficaudata
Loc*TOD
10,30.4
3.166
0.007
E. murrayi
Loc*TOD
7,34.8
4.575
0.001
140
Chapter 6: Lizard habitat choice
Insolation (Wm-2)
A.
16-17
15-16
14-15
13-14
12-13
11-12
10-11
9-10
B.
Position
Time of day
Tenv (0C)
0
10
50
70
96
Time of day
C.
L. mulleri
C. ruficaudata
Tb (0C)
A amicula
L. guichenoti
E. murrayi
16-17
14-15
13-14
11-12
9-10
8-9
Time of day
Fig 2. A. Profiles for levels of insolation and environmental temperatures available to
lizards across the gradient of shading generated using shade cloth covers over the
field enclosures throughout the course of the day. B. Profiles for Tenv in choice boxes.
Preferred temperature range (mean ± 68%CI) for the hot (all species except E.
murrayi – red bar) versus cold (E. murrayi – blue bar) lizard groups are overlaid on
available temperatures Tenv. C. Overall body temperatures, Tb, used by lizards in
experimental choice boxes, including the first hour of measurement in which lizards
were heating to preferred temperatures. All error bars represent 95% confidence
intervals.
141
Chapter 6: Lizard habitat choice
Thab(0C)
Sep - Oct
Nov - Dec
Jan - Feb
6-7
7-8
8-9
9-10 10-11 11-12 12-13 13-14 14-15 15-16
Time of day
Figure 3. Thermal profiles of environmental temperatures (Thab) available between
sun and shade in young plantation habitats throughout the course of a day in spring
(Sep – Oct), spring-summer (Nov – Dec) and summer (Dec – Jan). Upper profile is
sun temperature, lower profile is shade temperature. All error bars represent ±
2SE.Profiles are overlaid by mean preferred temperature ranges of ‘hot’ (all species
except E. murrayi – red bar) and ‘cold’ (E. murrayi – blue bar) lizards determined in
experimental choice boxes.
Overlaying preferred Tb and available Thab temperature ranges in figure four
identifies that achieving preferred temperatures in young plantation
environments would be challenging for all species that did not exhibit
behavioural flexibility. For all species except Eulamprus murrayi, Tb fell within
Thab ranges, but preferred temperatures were available only during the middle
of the day in Spring (Fig. 3). For Eulamprus murrayi whilst springtime Thab
overlapped preferred temperatures, by January young plantation Thab was
above the preferred temperature range at all times of the day (Fig. 3).
142
Chapter 6: Lizard habitat choice
Feeding study
A laboratory experiment assessing gut passage time was used to
examine whether preferred temperatures identified in field enclosures were
physiologically optimal for processing food. Previous studies have shown that
food-passage rates are often temperature dependent (Huey 1982, Beaupre
et al. 1993) and to consequently influence habitat choice (e.g. Pafilis et al.
2007, Homyack 2010). In January sixteen adults (7♀ and 7♂) of each
species used in the choice experiments were collected from the Mid-North
Coast, transported to Wollongong University, and allowed to adjust to
captivity for three weeks. Lizards were housed individually in a controlled
temperature room with a circadian fluctuation of 24-270C and photoperiod
L:D 12:12h. The smaller species were placed individually in 30 x 25 x 15cm
boxes and larger E. murrayi in 60 x 45 x 50 boxes. All boxes had a substrate
of natural leaf litter and wood shavings. Thermal gradients for basking were
generated by an overhead lamp above and a coiled heating wire (Resun
HTC-750, 55W ) beneath one end of each box on a 10:14 L:D photoperiod.
Water and food (Tenebrio larvae and Gryllus sp.) were available ad libitum.
Trials during the pilot study identified that L. muelleri would not adjust to
experimental enclosures, and this species was summarily excluded from
experimental testing. All females were palpated before testing to ensure they
were not gravid.
Testing for temperature effects on gut passage rate involved placing
lizards in 40 x 13 x15cm plastic tubs in controlled temperature cabinets set to
temperatures of 20, 25 or 300C, the mid-point of Thab available to lizards in
young plantations in spring, spring-summer and summer. Temperatures
143
Chapter 6: Lizard habitat choice
representing mid-winter and mid-summer (15 and 350C) were initially
included in a pilot study but were abandoned after establishing that 350C was
above the critical thermal maximum for Calyptotis ruficaudata, and was lethal
for Eulamprus murrayi, and at 150C <10% of individuals of all species
besides E. murrayi fed. Temperatures in cabinets varied <10C around the set
point temperature during trials. Tubs contained two retreats and were floored
with river sand. Once in the cabinets lizards were provided with a cold light
source and were left to acclimate for two hours prior to testing. A pilot study
using crickets marked with a fluorescent pigment (#JS-S03019, sunset
orange, Radiant Color Inc, Richmond) diluted in acetone in a 1:15 ratio and
painted onto crickets (which were then heated under a lamp to facilitate
evaporation of acetone), showed that gut passage was completed within 92h
in all test temperatures. It was assumed that the first faeces contained the
remains of prey consumed in that trial, as lizards were fasted for 96h prior to
feeding trials. During testing lizards were filmed in real time using a video
camera (JVC Everio), downloading to a video tape player (Sony LVX811).
These tapes were later reviewed and times of feeding and defecation
recorded using a stopwatch. Appetite was inferred from the total number of
prey items consumed. Gut passage rates were defined as the time between
the complete disappearance of the first prey into the mouth of the lizard, and
the first appearance of faeces. While a variety of other behaviours were
initially recorded, only gut passage time and appetite were finally analyzed as
they were not influenced by the novel environment (substrate, motion) in
experimental cages, whereas other behaviours often analyzed as indicative
of feeding efficiency (e.g. prey handling time, number of attempts etc.) rely on
144
Chapter 6: Lizard habitat choice
subjective observations of ‘normal’ behaviour and had the potential to be
compromised in the experimental enclosures.
Each test involved introducing five crickets (Gryllus sp.; each no more
than 3.0 ± 0.5% of the test lizard weight to standardize appetite against body
size (Bilcke et al. 2006) into tubs ten centimeters from the lizard via a small
tube. Additional crickets were introduced singly until an individual did not eat
or attempt to catch any further crickets for 10 minutes. After this point any
remaining crickets were removed, and lizards were maintained in their tubs at
the test temperature until faeces were produced. Individuals were allocated in
a random sequence to temperature treatments. In between trials, lizards
were returned to controlled temperature rooms for eight days of rest during
which they were fed ad libitum for four days and then fasted for four days
prior to the next testing. Each individual was tested once at each temperature.
Data Analysis
A mixed-effect repeated measures model was used to identify any
effect of temperature on gut passage time, using ‘species’ and ‘temperature’
as fixed effects and ‘lizard’ as the repeated factor. A repeated measures
design was necessary as each lizard was measured three times; once per
temperature. All of the continuous response variables were square-root
transformed so that the residuals of the final models were normally
distributed. This model was also used to identify whether appetite was
suppressed at temperatures to which lizards would not normally be exposed.
145
Chapter 6: Lizard habitat choice
Results
Temperature interacted with species to affect their appetite (F = 12,133
= 23.583, p < 0.001) and gut passage time (F = 9,112 = 12.729, p < 0.001) in
the laboratory experiments. Gut passage rates and appetite were lowest at
the spring temperature of 200C for all species. At 250C, Adrasteia amicula
had the greatest appetite and fastest rate of gut passage (Fig. 4), despite this
being lower than its preferred Tb of 300C in the field enclosures.
Lampropholis guichenoti differed by showing greatest appetite at 300C, in
accordance with its mean preferred temperature identified in choice boxes,
while its gut passage rates did not differ between 25 and 300C. Whilst field
enclosure data suggested Eulamprus murrayi should perform best at the
physiologically optimal temperature of 250C, there was no difference in either
gut passage rate or appetite between 25 and 300C (Fig. 4). Similarly, the
forest-associated Calyptotis ruficaudata was expected to show highest rates
of gut passage at 300C, but appetite did not differ between 25 and 300C,
although gut passage rates were fastest at 300C (Fig. 4).
146
Chapter 6: Lizard habitat choice
Table 3. Estimates of fixed effects for mixed models analysis of appetite and gut
passage rate for each lizard species. Results shown are for overall model for each
species. Significant values are in bold.
Species
L. guichenoti
df
133
Appetite
t
6.679
p
0.000
df
112
Gut passage rate
t
p
2.695
0.008
A. amicula
133
0.216
0.834
112
0.090
0.031
C. ruficaudata
133
16.762
0.023
112
4.888
<0.001
E. murrayi
133
0.772
0.014
112
9.049
<0.001
Hours
No. prey eaten
200C
250C
300C
Temperature (0C)
Fig 4. Appetite and gut passage rates of for the four species tested experimentally
at (200C) spring, (250C) spring-summer and summer (300C) temperatures available
in young plantations on the Mid North coast of New South Wales. All error bars are
±2SE.
156
Chapter 6: Lizard habitat choice
Discussion
This study demonstrates that habitat choice in the small scincid lizards
examined in this study is constrained by behaviour and that this can influence
temperature-dependent physiological processes such as food assimilation
rates. Such outcomes can have flow-on consequences for the diversity of
lizard assemblages found in young native plantations. The summertime
thermal environment in young plantations appear to be physiologically
stressful for all lizard species, and while temperatures optimal for digestive
efficiency can be achieved, they require the species using this forest type to
exhibit flexibility in both activity time and substrate choice. Those species that
did not possess this flexibility were excluded from young plantations. I
discuss reasons for this in relation to the three hypotheses initially proposed.
Hypothesis 1- habitat generalist species have a broader preferred
temperature range than habitat specialists
The breadth of preferred temperature ranges are ultimately
constrained by the temperature-dependence of physiological processes
(Huey 1991, Blouin-Demers & Nadeau 2005). However for heliothermic
reptiles, achieving the preferred temperature range relies on the availability of
preferred thermal microenvironments in a habitat, the flexibility of behavioural
mechanisms which adjust rates of heat exchange, and the need to balance
predation risk with the need to bask (Heatwole 1977, Huey & Slatkin 1976,
Heatwole & Taylor 1987, Vickers et al. 2011). In opposition to my initial
hypothesis the generalist Lampropholis guichenoti did not have a broader
157
Chapter 6: Lizard habitat choice
preferred temperature range than the less widely distributed skink species
examined in this study. While young plantations could thermally satisfy L.
guichenoti’s 300C physiologically optimum temperature (Fig 5.), to achieve
the narrow preferred temperature range it showed in the habitat-choice
enclosures, L. guichenoti would need to restrict activity to the middle of the
day in the sun in spring, but by summer would need to remain exclusively in
shaded microhabitats or confine it’s activity period to mornings and
afternoons (Fig. 5). L. guichenoti is known exhibit flexibility in behaviour
(Prosser et al. 2006) and substrate choice (Penn et al. 2003, Fischer et al.
2005). Such flexibility explains its wide range generally, and its use of a
variety of habitats with different structures in this study (Chapter 2). In
addition to young plantations providing optimal temperature, the persistence
of L. guichenoti in the hot environment of young plantations throughout an
annual cycle may also be related to its tolerance of dry hydric conditions in
the nest environment. Such conditions are known to affect the body mass of
hatchlings, but to have little effect on other phenotypic traits related to fitness
such as sprint speed or growth rate (Du & Shine 2008).
The high preferred body temperatures identified in this study are
typical of diurnal species like Lampropholis guichenoti, but cryptozoic species
are often characterized as having low preferred and optimal temperatures
(Huey & Bennett 1987). However, the cryptozoic Lerista muelleri and
Calyptotis ruficaudata had preferred temperature ranges matching that of the
generalist L. guichenoti. For Lerista muelleri this is unsurprising, as high
preferred temperatures are typical of the Eyrean (central Australian) radiation
of Sphenomorphine skinks (Spellerberg 1972b, Greer 1980, Bennett & John-
158
Chapter 6: Lizard habitat choice
Alder 1986, Skinner et al. 2008), and the majority of species of both Lerista
and its sister genus Ctenotus are thought to have radiated in association with
the historical aridification of Australia (Rabosky et al. 2007). While the
plantation environment is not physiologically limiting for L. muelleri in spring
and early summer , its rigid activity times and preferences for low levels or
irradiation coupled with a strong preference for complex substrate, is likely to
hamper the use of young plantations by these species. Calyptotis ruficaudata,
while also a member of the diverse Sphenomorphine skink group (Reeder
2003), radiated from a Bassian (coastal southeastern Australia) lineage
which typically prefer lower temperatures (Huey & Bennett 1987). Despite
this phylogenetic tendency, the forest-associated Calyptotis ruficaudata in
this study displayed optimal and preferred temperatures similar with those of
the woodland L. muelleri and L. guichenoti. While the plantation thermal
environment is not physiologically limiting for either L. muelleri or C.
ruficaudata in spring and early summer. L. muelleri’s rigid activity times and
preferences for low levels of irradiation coupled with a strong preference for
complex substrates is likely to hamper its use of young plantations.
Hypotheses 2 - habitat-specialist species should show stronger preference
for particular substrate types than habitat-generalist species
Specialist species exhibited two patterns of habitat use in this study. In
support of hypothesis two, the forest specialist Eulamprus murrayi did not
separate preferences for thermal and structural environment, and chose
habitats that were consistent with a strong preference for low irradiance and
complex structure. Such limited use of cues that link with particular habitat
159
Chapter 6: Lizard habitat choice
choices are a typical trait of habitat-specialist species (Greenville & Dickman
2009). Unlike the situation for other lizard species examined, the midsummer operative temperatures in plantations exceeded the critical thermal
maximum E. murrayi and would preclude its use of this habitat outside of
spring and autumn. This coupled with the sedentary nature of this species
and it’s rigid preference for low-light environments and complex substrates,
suggests that neither young nor old native plantations could act as habitat for
E. murrayi, even if plantation management included diversifying ground layer
complexity, as plantations are typically light-saturated due to canopy
disturbance.
However, in refute of hypothesis two, the plantation specialist
Adrasteiascincus amicula, did not choose habitat based on a preference for
substrate type. While A. amicula consistently preferred complex substrates in
experimental enclosures its acceptance of simple substrate in young
plantations in the field reflects high behavioural flexibility. While A. amicula is
not truly a ‘specialist’ to young plantations, its preference for these forests in
the study area (Chapter 3, 5) is unusual given its typical association with
moist closed woodland and heath (Cogger 2006). Its failure to use old
plantations or logged native forest in the study area is unlikely to be mediated
by competition, as no other skink species of equivalent size were detected in
the study area. A more likely explanation relates to its opportunistic ability to
exploit the ‘new’ habitat young plantations represent, which is promoted by its
small size, and thus ability to find refuges in the plantation understorey that
has typically very little leaf litter depth. It may also be related to predation
pressure, which has been demonstrated to force the use of suboptimal
160
Chapter 6: Lizard habitat choice
microclimates in lizards (Díaz et al. 2005), and it is notable that the diversity
of invertebrates and the abundance and diversity of lizard predators
(e.g.dasyurid mammals) increases in old plantations and logged native
forests.
Hypothesis 3 – habitat specialists should have the most efficient gut passage
time in temperatures common to the habitats in which they specialize
This study did not identify any association between habitat
specialization and gut passage time. For Adrasteiascincus amicula gut
passage time was maximal at 250C, while for Eulamprus murrayi it did not
differ between 25 and 300C. While it seems counterintuitive that habitat
specialists do not perform optimally at the temperatures they behaviourally
select, partial co-adaptation between behaviour and digestive efficiency may
account for the disjunction between preferred and optimal temperatures.
Huey and Bennett (1987) believe partial coadaptation to result from a faster
rate of evolution of preferred temperature than optimal temperature. This
produces disjunction between the temperatures that maximize fitness, and
those which allow an individual to be active in a habitat. There is no
consensus of how common partial coadaptations are among lizards,
(Angilletta et al. 2002a), and whether such conditions typify Australian skinks
(Garland et al. 1991), but Angilletta et al. (2002b) suggests that the outcome
of this trade-off is that thermoregulatory behaviour favours optimal physiology
over performance due to the direct fitness costs associated with not
assimilating energy efficiently. The results of the present study do not agree
with those of Angilletta et al. (2002b) but identify A. amicula as maintaining
161
Chapter 6: Lizard habitat choice
preferred temperatures that are suboptimal for digestive rate. While many
ectotherms do behaviourally select suboptimal temperatures, Hutchison &
Maness (1979) and Martin and Huey (2008) argue that they may do so to
avoid the often fatal consequences of attaining body temperatures only a few
degrees above their physiological maxima. The persistence of A. amicula in
young plantations through the summer (Chapter 2) when thermal conditions
are persistently above those that are physiologically optimal suggests that
the benefits they gain by exploiting empty niches in the ‘new’ habitat created
by plantations, outweighs the costs of suboptimal physiological performance.
Similar situations are described by Huey and Bennett (1987) as “adequacy
rather than optimality guiding the evolution of thermal performance and
behaviour”.
Such disjunctions between performance and physiology can arise
when optimal temperatures are evolutionarily static (e.g. Van Damme et al.
1990, Angilletta et al. 2002a, Rodríguez-Serrano et al. 2009). In this study
low optimal temperatures probably represent the ancestral state of A.
amicula, a temperate, south-eastern Australian endemic (Wells 2010). The
high preferred temperatures that have allowed A. amicula to radiate from
closed woodland into young plantations may represent an evolutionary
pressure that will, in the future, shift optimal temperatures upwards through
co-adaptation. Further, because all physiological processes do not share the
same optimal temperature (Van Damme et al. 1991, Du et al. 2000,
Ojanguren et al. 2001, Angilletta et al. 2002b), it is possible that the preferred
temperature range identified for A. amicula optimizes some other measure of
performance that was not investigated in this study (the ‘multiple optima’
162
Chapter 6: Lizard habitat choice
hypothesis, Bustard 1967, Pough 1980, Huey 1982). Temporal modifications
in behaviour to meet multiple optima are common for ectotherms (Angilletta
et al. 2002b), and as an active shuttling heliotherm with very small size (SVL
30mm), and thus very little thermal inertia (Bell 1980, Garrick 2008), A.
amuicula’s ability to rapidly change body temperature via behaviour to ensure
optimal physiological status is probably easy for this species to achieve, and
could foster its persistence in young plantations. That A. amicula experiences
multiple optima and adjusts preferred temperature accordingly is supported in
this study by the shift in activity observed from the active morning period, to
the inactive afternoon period at the cooler end of the gradient, and the
associated decline in body temperature, towards the digestively optimal 250C.
Such non-random retreat selection is recognized as important to determining
habitat selection in reptiles (e.g. Grant & Dunham 1988, Pringle et al. 2003,
Goldsbrough et al. 2006, Andersson et al. 2010, Martín & López 2010, Pike
et al. 2011), and offers a good explanation for the disjunction between
preferred and optimal temperatures exhibited by A. amicula.
In contrast to Adrasteiascincus amicula, the mean preferred
temperature range for Eulamprus murrayi corresponds with its optimal
temperature for food passage and appetite. As a rainforest endemic
(O’Connor & Mortiz 2003), this low optimal temperature was expected for E.
murrayi, but the invariance of response to temperature in both physiological
parameters measured was not. While researches have often identified strong
inverse correlation between temperature and gut passage time (e.g.
McConnachie & Alexander 2004, Bilcke et al. 2006), there are cases where
gut passage time (Alexander et al. 2001) and other measures of
163
Chapter 6: Lizard habitat choice
performance such as sprint speed (Angilletta et al. 2002b) do not increase
with increasing temperature. It seems that for E. murrayi and for the other
skink species examined, the optimal temperature range for digestion is broad.
This breadth may reflect the historic radiation of these skinks either out of
mesic habitats, in the case of E. murrayi (O’Connor & Mortiz 2003) and L.
amicula, or out of arid habitats into mesic ones in the case of Lerista muelleri.
Conclusions
This study demonstrates that young native plantations can offer a
highly seasonal resource for small skinks, and that in the system studied low
spring and high summer temperatures could preclude use of this habitat by
lizard species with rigid preferences for particular body temperatures and
physiological performance, if thermal refuges do not exist. Experimental tests
of thermal and substrate preference reveals the simple substrate found in
young plantations is not preferred by any lizard species examined. This
suggests that substrate enrichment is needed to increase skink diversity, and,
by association, the diversity of other species as well. While we might expect
to see species of low mobility persisting in young plantations by exploiting
microclimatic variability associated with habitat edges (Chen et al. 1993,
Laurance 2004), such seasonal shifts in habitat use of low mobility fauna
remain poorly documented in terrestrial environments (Seebacher & Alford
2002), and are largely unexplored in plantations. Understanding these sorts
of seasonal movements may be important however, as they have
ramifications for the way habitat enrichment in plantations could be achieved.
164
Chapter 6: Lizard habitat choice
The management of slash is currently being investigated as a means
of enhancing understorey complexity in plantations (Matthews et al. 2010).
Enhancing habitat complexity by simply leaving slash is unlikely to generate
thermal refuges cool enough to allow persistence throughout the annual
cycle. My results suggest that, habitat enrichment protocols that would need
to include coarse woody debris piles, cover boards or some other measure of
ground cover able to decrease irradiance and reduce microhabitat
temperatures by more than five degrees in summer to permit their year-round
residence, and attract cryptozoic species. More thermally targeted refugia
such as stacked log piles are likely to better benefit these cryptozoic species,
in particular C.ruficaudata, which shows some tolerance of higher irradiance,
and so may use young plantations with the provision of necessary habitat
selection cues. The case for attracting L. muelleri to young plantations is less
certain, primarily because other species of Lerisa show strong preferences
for uncompacted substrates that reduce the energetic costs of movement
(Greenville & Dickman 1999), and soil compaction associated with machines
and cattle’s grazing is typical of managed plantations. The success of those
species already common in young plantations is attributed to high
behavioural flexibility which allows these species to exploit the mismatch
between ecologically and physiologically optimal temperatures.
165
Chapter 7: General discussion
Chapter 7
General Discussion
The value of plantations as habitat – an overview
As for all countries globally, Australia’s unique biota are under threat
from changes in land use, altered fire regimes and hydrology, and the spread
of invasive species, pathogens and diseases. These threats have generated
a loss of biodiversity in the last 200 years that encompasses the
disappearance of up to 30 per cent of small mammals, as well as numerous
plants, birds, reptiles, fish and amphibians. Despite the adoption of global
and national policy to slow current rates of species decline, Australia is still
losing biota at an increasing rate (DEWHA 2009). This rate of loss is likely to
be accelerated by climate change which is expected to place already
stressed and vulnerable species at greater risk (Beeton et al. 2006).
There is recognition that national reserve systems are inadequate to
protect biodiversity (Rodrígues et al. 2004). Reserve size is often insufficient
to buffer ecosystems against large-scale disturbances such as fire and
climate change, and reserve connectivity is insufficient to accommodate
large-scale animal movements often associated with these disturbances
(Paton & O’Connor 2010). Native plantations can play many roles in
mitigating biodiversity loss, if they enhance and extend native forests. Further,
afforestation with plantations has the potential to address one of the crucial
issues in rural biodiversity conservation; the restoration and maintenance of
fauna in partly cleared rural landscapes (Loyn et al. 2008). This research
166
Chapter 7: General discussion
identified that providing habitat for fauna is one role native plantations can
fulfill.
This research in context
This research conducted in on Australia’s East coast in small-scale,
afforested and reforested native plantation monocultures in close proximity to
forests, identified that young and old managed plantations can support
vertebrate assemblages as species rich as those in old growth forests.
Borsboom et al. (2002) conducting research in a similar plantation system in
south-east Queensland, identified lower vertebrate richness in plantations
less than four years old in comparison to adjacent logged native forests, but
similar richness between forests and native plantations 4-40 years old. Birds
only, showed lower richness in young plantations than forests at the taxonlevel. This thesis extended Boorsboom et al.’s (2002) research by including
comparisons of faunal richness in old growth forests of high faunal diversity
with logged native forests and young and old plantations, and by targeting
herpetofaunal and ground mammal responses to plantations. This research
found that the mean species richness and abundance of birds, mammals and
herpetofauna was statistically similar in logged and old growth forests and in
structurally simpler young and old plantations. Whilst similar cross-taxa
responses to plantations have been documented previously in old,
ecologically managed plantation monocultures of Araucaria angustifolia in
Brasil (Fonseca et al. 2009), this thesis is the first to identify similar species
diversity responses to commercially managed young plantations across
animal taxa, and between old growth forests and native plantations in
167
Chapter 7: General discussion
forested environments. This result contradicts taxon-specific meta-analyses
of bird (Nájera & Simonetti 2009) and mammal (Ramírez & Simonetti 2011)
use of native plantation monocultures, which find that species richness in
plantations increases with structural complexity. Whilst structural complexity
did influence abundance in this research, species richness was maintained
by a high species turnover in young and old plantations, where forest species
loss was offset by incursions of woodland and generalist species. This result
contrasts that of Hobbs et al. (2003) whom identify young native plantations
in large-scale plantation systems in fragmented forest landscapes in Western
Australia as supporting less species rich assemblages than forest remnants.
Faria et al. (2007) also found that in old, ecologically-managed Brazilian
cacao plantations reduced forest cover in the landscape mosaic generated
impoverished plantations irrespective of the biological group considered. The
retention of biological legacies (Tews et al. 2004) and high diversity in the
regional species pool (Tscharntke et al. 2012) all influence local species
diversity, and were likely to have promoted species replacement in
plantations in this research. The differences in results from this research and
that of Hobbs et al. (2003) suggests that whilst commercially managed,
young native plantations can provide habitat for a variety of species,
landscape context and immigration rate is likely to be equally as important as
local vegetation heterogeneity in influencing the development of diverse
vertebrate assemblages.
In broad connection to native forest, without accessory management
to enhance biodiversity beyond the retention of legacy trees and riparian
strips, and with the impact of cattle grazing, in this research native
168
Chapter 7: General discussion
plantations six years old supported diverse faunal assemblages including
woodland birds and open-habitat herpetofauna. While this result appears
positive, many authors (Dunning et al. 1992, Didham et al. 1996, Peterson et
al. 1998, Barbour et al. 2003) stress that ecosystem function, rather than
species richness (which may respond to disturbance slowly - Vellend et al.
2006), is a better indicator of ecosystem health. Both this research (Chapter
3) and that of other authors (Borsboom et al. 2002, Lindemnmayer & Hobbs
2004, Kanowski et al. 2006, Zurita et al. 2006, Brockerhoff et al. 2008) agree
that assemblages shift towards generalist species in native plantations, and
that forest-specialist species from all faunal groups are poorly represented.
The lack of nectivorous guilds, sub-canopy specialists, and the dominance of
generalist ground feeders in both young and old plantations points to
persistently compromised pollination and plant dispersal systems, and
suggests that even in older plantations where faunal assemblages are
diverse, ecosystem function is unlikely to operate as it does in forests.
Woodland birds
In a nationwide review of Australian bird diversity, Paton & O’Connor
(2010) identified monocultures generally as providing poor habitat for birds.
This thesis and other research comparing bird diversity between forests and
monoculture plantations in both fragmented forest landscapes in Australia
(Loyn et al. 2007) and continuous forested landscapes in Australia
(Boorsboom et al. 2002), South America (Zurita et al. 2006) and Africa
(Farwig et al. 2008), contradict Paton and O’Connor’s (2010) statement. This
body of research collectively identifies that native plantations can support
high species richness of canopy and ground feeding woodland birds. Loyn et
169
Chapter 7: General discussion
al.’s (2007) results find that stand-level habitat features are stronger
predictors of bird richness than landscape context. If commercially managed
plantations typically retain open sub-canopy structure throughout the rotation
cycle, as was identified in this research (Chapter 3), and landscape context is
less important than local vegetation structure in influencing bird species
richness, then it is likely that native plantations can promote incursions of
woodland birds into forested environments.
In this research plantations supported diverse assemblages of
woodland birds after a relatively short six-year time period. This result
suggests some potential for woodland birds to expand their ranges into
forested environments using native plantations as a conduit. This range
expansion may be facilitated by the vegetation structure and thermal
environment in managed young plantations, which can remain hot and open
after 30-years of growth and management (Chapter 2). Reino et al.’s (2009)
research examining the invasion of afforested plantations by open-country
birds suggests that in a Mediterranean forest-farmland system, a mosaic of
young and old plantation ages influences the persistence of woodland birds
in the landscape as woodland species respond more positively to hard (old)
than soft (young) edges. Certainly exotic plantations are known to attract
open-habitat birds both in Australia (e.g. Curry et al. 1991) and in temperate
ecosystems overseas (e.g. Paquet et al. 2006), and birds in native plantation
systems in Australia use plantation edges differently to interiors (e.g. Hobbs
et al. 2003). Thus Reino et al.’s (2009) assertion that plantation age mosaics
foster incursions of woodland birds into forested landscapes by providing
favoured edge habitats is plausible for Australian plantation systems.
170
Chapter 7: General discussion
Woodland bird incursions into plantations are positive if they increase
regional diversity, but negative if plantations provide corridors for invaders
which change community dynamics by increasing local levels of competition
or predation (e.g. Poulin et al. 2011), or disrupting local adaptations by
allowing incursions of novel genes (see Bennett 1998, 2003 Table 4-3 for a
review). While these issues have been addressed extensively in the
fragmentation literature, the role of native plantations as corridors or matrix
has only recently begun to be addressed by researchers (e.g. Bentley et al.
2000, Kavanagh et al. 2005, Barlow et al. 2007a, Brockerhoff et al. 2008,
Lindenmayer et al. 2009, 2010). The impact of plantations as conduits for
woodland species invasion needs investigation before predictions about the
impact of native plantations on birds in adjacent forests are possible. Such
predictions will require long-term studies as the global native plantation
estate matures.
Forest species
General statements in the plantation literature identify native
plantations as poor habitat for forest species (Lindenmayer & Hobbs 2003,
Brockerhoff et al. 2008). The results of this thesis (Chapter 3) suggest this
statement needs qualification. In this research native plantations in broad
connection with forests supported 46% of forest bird species as well as 40%
of mammals, and 18% of herpetofauna (Chapter 3). Whilst the mean
richness of forest species was lower in plantations than forests for all faunal
groups, old plantations supported similar abundances of forest fauna from all
taxa. Lindenmayer et al. (2003) suggest that knowledge of species-specific
preferences for habitat attributes is more important in predicting how a
171
Chapter 7: General discussion
species will use habitat than anthropogenic concepts like ‘forest’ or ‘nonforest’. From this perspective the results of this research suggest that
plantations only negatively affected those forest species intolerant of lowfloristic diversity and structural complexity. Certainly, for the plantation
system investigated in this study, a generalization about the effect of
plantations on forest species must be qualified to state that only a percentage
of the forest species in the species pool were excluded from plantations.
Small mammals
This research identified that even without complex understorey
condition, young and old native plantations in close proximity to native forests
can support assemblages of small mammals equally as diverse as those in
old growth forests (Chapter 3). This result contrasts those from a study in
fragmented Araucaria vine forests and native Araucaria plantations in
southeastern Queensland (Bentley et al. 2000) which found an increase in
mammal richness and abundance with increasing sub-canopy complexity. A
meta-analysis by Ramírez and Simonetti (2011) identified that small
mammals increase in response to structural complexity independent of
plantation type in commercially managed-landscapes. Similarly Holland &
Bennett ‘s (2007) species-based analysis of landscape-scale habitat use by
small mammals in fragmented eucalypt forests also found that species
richness increased with vegetation complexity. Boorsboom et al. (2002)
found in their analysis of native plantations in broad connection to forests that
small mammal communities in simply-structured young plantations were
depauperate compared with those in older plantations and forest remnants.
My results contradict these findings; whilst young plantations showed trends
172
Chapter 7: General discussion
towards lower forest mammal richness and lower small mammal richness
overall, richness did not differ significantly between plantations and old
growth forests (Chapter 5). This result supports work by Mitchell et al. (1995)
and Mengak and Guyunn (2003) from native pine plantations in broad
connection to continuous pine forests in the United States, which identifies
that the availability of preferred microhabitat features influences mammal
diversity more than stand age or canopy structure. Significant taxonomic
replacement occurred in both Mengak and Guyunn’s (2003) study, and in my
research (Chapter 3) where there was a shift from rodent-dominated forest
assemblages to dasyurid-dominated plantation assemblages and species
preferring simpler vegetation structures. Whilst local vegetation structure was
likely to have ultimately determined species diversity in plantations, the
species pool available in an unfragmented forest landscape was large
enough to allow species replacement, resulting in the development of diverse
ground mammal assemblages in plantations. Taxonomic shifts were notably
lacking in the studies by Ramírez and Simonetti (2011), Boorsboom et al.
(2002) and Bentley (2000) which compared plantations with fragmented
forests, stressing that as for birds, landscape context and pathways for
immigration mediated by retained vegetation or proximity to forests are likely
to be important factors promoting small mammal diversity in native
plantations.
Food availability
Decreased body size as a result of reduced precipitation is a global
phenomenon only recently being investigated in relation to organism
173
Chapter 7: General discussion
development and growth (Sheridan & Bickford 2011). In commercial
plantation systems that have lowered soil moisture compared to forests
(Chapter 2) and are generally structurally simple and exposed to high levels
of disturbance, there is high potential for invertebrate fauna of larger bodysizes to be lost, so reducing available prey, and potentially insectivore
abundance. This research identified significant decreases in invertebrate
body size moving from old growth native forests down the gradient of
structural complexity to young plantations (Chapter 4). Jelaska et al. (2011)
identify a similar response to plantation age by invertebrates in native beech
plantations in Croatia. This decrease in invertebrate size occurred in concert
with a lower abundance of large and medium insectivores in young
plantations. However, both this research and that from exotic plantation
monocultures (Cunningham et al. 2005, Samways et al. 1996, Prieto-Benítez
& Méndez 2010) identified that invertebrate assemblages were equally
diverse and abundant in forests and young plantations. Whilst invertebrates
were smaller and less abundant in plantations than forests, they were equally
as speciose and palatable, and insectivores using young plantations could
access a broader range of preferred prey types than were available in old
plantations or native forests. Hence lower insectivore abundances in young
plantations were more likely to be driven by the scarcity of refuges than prey
availability.
Matrix quality
Current plantation research recognizes that the quality of matrix
habitat and its management influences local species richness and incidence
174
Chapter 7: General discussion
and so can mediate plantation diversity (Ricketts 2001). How matrix habitats
influence diversity depends on whether the matrix is defined as the dominant
form of vegetation or as the area that is most disturbed (see Kupfer et al.
2006 for a discussion). In landscapes dominated by continuous forests
where in plantations are relatively small, forests are the matrix. Comparisons
of forest matrices and exotic plantations in both large and small-scale tropical
and temperate forest systems have identified that plantations often support a
lower species richness of beetles (Yu et al. 2006, Henríquez et al. 2009)
birds and ground mammals (Gjerde & Sætersdahl 1997, Lindenmayer et al.
2000, Barlow et al. 2007a).
Chapter five of this thesis analyzed the potential of the grazed forest
matrix to act as a source of recruits into abutting native plantations. My
results identified that despite contrasting vegetation structure between young
plantations and the adjacent forest matrix, small mammal and reptile
assemblages were equally species rich in both habitats, and that plantation
and forest assemblages were dominated by generalist species. Similar
richness between forest and matrix has been observed previously when
comparing low contrast habitats for ants in the Amazonia savanna
(Vasconcelos et al. 2006), and for ground mammals in pine-afforested
Afromotane grasslands in South Africa (Johnson et al. 2002). Bihn et al.
(2010) assert that for ants in Atlantic forest remnants in Brazil, a lack of
specialist species in assemblages despite high species richness overall,
indicates that habitat quality is poor. This research disagrees with Bihn et
al.’s 2010 assertion, and finds that whilst cattle-grazed forest matrices lacked
175
Chapter 7: General discussion
forest specialist species they supported forest generalists, and ground faunal
assemblages equally as rich as those in old growth forests in the region.
Cattle-grazing in the forest matrix more strongly influenced smallmammals than herpetofauna, and influenced the pool of species available to
recruit into young plantations (Chapter 5). For mammals whilst grazing may
have reduced mammal diversity in the forest matrix itself, strong preferences
for complex habitat features were more likely to preclude forest species
recruiting to young plantations. For herpetofauna, grazing may have
increased the permeability of the matrix, with a resultant influx of thermophilic
species into plantations. The disparity in diversity benefits for herpetofauna
and mammals suggests native plantations need to be positioned in the
landscape in proximity to both grazed and ungrazed forests to maximize
recruitment across multiple taxa. Whilst implementing such a design will rely
on the site-specific factors, it is a worthy aim for inclusion in the process of
afforesting pastures with native plantations, as current research identifies
fragmentation as a driver that may render Eastern Australian eucalypt forests
susceptible to large changes in ecosystem function, and ultimately
biodiversity decline (Laurance et al. 2011). By understanding whether
plantations differ in permeability with individual species choices and proximity
to source populations, managers can attempt to minimize afforestation that
fragments forest faunal assemblages, and in doing so generate plantation
systems that provide both local and regional benefits to forest fauna.
176
Chapter 7: General discussion
Plantations and the thermal environment
Floristics, vegetation structure and plant orientation all play a role in
determining microclimatic diversity at the ground level. While plantations of
endemic trees species may be more likely to approximate thermal
microclimates at the ground level than exotic species, canopy cover is the
strongest determinant of thermal environment (e,g, Porté et al. 2004, Rambo
& North 2009). Reducing canopy complexity in forest necessarily leads to an
increase in the range of microclimates experienced by organisms at the
forest floor, which in turn may increase in biodiversity (Hanley 2005, Weng et
al. 2007). This research is the first to identify that, as for exotic plantations,
the vegetation structure and associated microclimate in young and old native
monocultures and logged and old growth native forests follows levels of
canopy reduction. The greater the loss of canopy, the higher the maximum
temperature at the ground level (Chapter 2), which in summer results in both
young and old plantations having a more variable microclimate than forests
and generates a temperature difference approximating 200C at its greatest
point. This temperature differential may be physiologically limiting to plants
and animals using plantations, particularly forest species most likely to recruit
to plantations from the abutting forest matrix. Chapter six adopted an
ecophysiological approach to identifying physiological limits to lizard diversity
in young plantations, using small skinks as a model.
This research is the first to conclusively demonstrate that young
plantations can be physiologically limiting to some forest species. Numerous
studies identify that habitat choice in reptiles (e.g. Vitt et al. 2005,
Goldsbrough et al. 2006, Pike et al. 2011), mammals (e.g. Hill 2006, Issac et
177
Chapter 7: General discussion
al. 2008) and frogs (e.g. Vallan 2002) is influenced by available thermal
microclimate. Habitat choice in the small scincid lizards examined in this
study was constrained by both behavior and physiology and this had flowthrough consequences on lizard species richness in young native plantations
(Chapter 6). The summertime thermal environment in young plantations was
stressful for all lizard species, and while temperatures optimal for digestive
efficiency could be achieved, they required the species using this forest type
to exhibit flexibility in both activity time and substrate choice. Those species
that did not possess this flexibility could not use young plantations. Whether
these results apply widely to other ectotherms is unknown, but this chapter
suggests that identifying whether a species is able to separate preferences
for habitat structure from those for thermal environment, will allow
researchers to predict the potential for those species to use limiting habitats
like young plantations.
Plantations and climate change
Climate change is predicted to be one of the greatest drivers of
ecological change in the coming century (Lawler et al. 2009). This research
(Chapters 2 and 6) identifies that young plantations are likely to be
physiologically stressful for those biota that prefer cool microclimates and for
all species during the summer. Thus whilst plantations under current climatic
conditions limit some species, the potential for them to become even less
suitable with climate warming is high. For ground fauna of limited mobility
that are already living at the extreme of physiologically tolerable limits
(Chapter 6), increasing temperature may have directly negative
consequences for their persistence in native plantations, and thus for
178
Chapter 7: General discussion
plantation diversity as a whole. This is particularly true of species which
currently persist in plantations by exploiting microclimatic variability
associated with habitat edges (Chen et al. 1993, Laurance 2004). However,
for herpetofauna microclimatically-driven species losses in plantations may
be offset by an increase of thermophilic species, which in the area studied
can permeate through the forest matrix (Chapter five). While there is very
little work available that examines the role of microclimate in influencing
habitat selection in native plantations, such research is increasingly important
as the range shifts associated with climate change occur.
The way forward
Developing plantation management practices that concurrently
conserve biodiversity and maintain profitability is a key component of multiuse forest management, and is becoming increasingly important as the
plantation estate expands. Identifying the variables that enhance the
occurrence and survival of plants and animals in plantations is a mandatory
step toward developing effective multi-use plantations (Tews et al. 2004,
Stephens & Wagner 2007, Nájera & Simonetti 2010). This thesis combined
landscape ecology, physiology and population ecology to identify that in
proximity to continuous forests commercially managed, small-scale, young
and old Eucalyptus plantations can support equivalent faunal richness to old
growth forests. However, the lack of nectarivores and arboreally-feeding
insectivores suggests the ecosystem services these functional groups
provide were absent from plantations.
179
Chapter 7: General discussion
The correlation between reduced abundance and understorey
complexity for birds, mammals and forest reptiles in plantations provides an
opportunity to employ a set of management practices which could enhance
future plantation diversity (Florence, 2004). Managed young plantations in
particular, have a greater potential to become functionally diverse habitats for
fauna with changes in plantation design and management that increase the
heterogeneity of thermal environments. The retention of coarse woody debris
(reviewed by Stevens 1997) is known to increase faunal diversity in
plantation landscapes. While the influence of overstorey vegetation structure
on understorey microclimates need further research (Parrotta et al. 1997),
increasing ground-level complexity will directly diversify understorey
microclimates, which in turn may increase herpetofaunal diversity in
plantations with knock-on effects for predators. Including preferred
microhabitat features like coarse woody debris and targeting enrichment
towards linear strips of low, shrubby vegetation increases forest mammal
recruitment into young (e.g. Holland & Bennett 2007) and old plantations
(e.g. Moser et al. 2002), and can promote mammal movement within
plantations matrices (e.g. Predevello & Viera 2010). Christian et al. (1998)
identified such enrichment increased bird diversity in poplar plantations in the
northeastern United States, and birds are positively associated with coarse
woody debris in Southeast Australian floodplain forests (Mac Nally et al.
2001). Experimental manipulation of habitat enrichment techniques to
understand the both costs to production and the value to fauna is an avenue
of value for further investigation for plantation managers.
180
Chapter 7: General discussion
Methods for improving faunal diversity in plantation environments have
been discussed comprehensively by Kerr (1999), Hartley (2002),
Lindenmayer and Hobbs (2004) and Brockerhoff et al. (2012). This thesis
identifies further avenues of research in small-scale native plantations that
will advance understanding of the capacity of native plantations to increase
faunal diversity. These include :
1) quantifying the of degree of faunal exchange between plantations and forests and
the capacity of disturbance in adjacent habitats to influence faunal diversity in
plantations. Lindenmayer et al. (2009) identify that management of pine stands in
large-scale systems where pine comprises the landscape matrix negatively effects
faunal diversity in adjacent remnant forest patches. Understanding whether
Lindenmayer et al.’s (2009) results apply in small-scale native plantation systems
that experience dynamic movement of fauna, will allow managers to gauge the
impacts of end-rotation harvesting on fauna in retained plantation stands and so
assess the importance of managing plantations for multiple age classes.
2) identifying the potential of native plantations to act as ecological traps through higher
predation or lower breeding success rates. Ecological traps occur when animals
choose habitat in a maladaptive way because they do not perceive differences in
habitat quality, which eventually leads to population extinction (Delibes et al. 2001).
Battin (2004) states that ecological traps are more common in anthropogenically
generated habitats that arise quickly. Mid-rotation native plantations may act as
ecological traps because they resemble forests and so encourage immigration, but
have the potential to promote higher mortality risks and poorer breeding conditions
than forests due to their lack of sub-canopy structure and are likely to supply high
temporal variation in plant resources. As Gilroy & Sutherland (2007) state, activities
that mitigate the effects of ecological traps could help to minimize the impact of
habitat change on natural environments. For native plantations this would entail
reducing management throughout the plantation cycle allowing the development of
some level of understory and adopting longer rotations which would allow
181
Chapter 7: General discussion
populations to either evolve new habitat preferences or adapt to changed
environmental conditions. As the nature of ecological traps is often transient, future
research to clarify whether native plantations act as ecological traps needs to be
staggered across plantation ages and should include an assessment of proximity to
forest, which will influence the potential for immigration for all animals.
3) investigating the role of spar plantations in buffering forest from
microclimatic extremes and increasing the functional connectivity of
plantation networks for forest species. Knowledge of animal use of spar
plantations is particularly limited in native plantation systems. However, if
spar plantations can provide habitat for those species using young
plantations, they have strong potential to provide alternative habitat when
staged management occurs in plantations. Spar plantations are cooler
than plantations and so may represent thermal barriers to ectotherms and
competitive extra-regional species moving between plantations and
forests. Clarifying how effective spar plantations are as barriers will
provide better understanding of the role of spar-aged stands as part of the
plantation age mosaic. Such knowledge is currently valuable for
Australian systems as 22.5% of the national hardwood plantation estate
will mature to spar age in the next five years (Gavran 2013). This
research is likely to increase in importance as range shifts associated with
climate change escalate.
4) clarifying the role of retained habitat features and ground-level complexity
in increasing alpha diversity in both young and old plantations. Whilst a
number of studies have investigated positive diversity benefits of including
retained habitat features in plantation designs (e.g Hsu et al. 2010,
riparian strips, Law & Chidel 2002 – habitat trees, Cummings & Reid
182
Chapter 7: General discussion
2008- slash), there is little Australian research into faunal responses to
less cost-intensive management strategies such as retaining/burning
slash, that can be implemented throughout the rotation cycle. Retained
coarse woody debris is known to positively benefit fauna and offset
disturbance arising from mid-rotation management in studies from North
America (e.g. Stevens 1997, Owens et al. 2008). Replicating such
research in Australian plantation systems and identifying the management
costs that occur in conjunction with retaining coarse woody debris could
identify a cost effective and easily achievable means of increasing native
plantation biodiversity.
Conclusions
This thesis provides a response to the call for greater knowledge of
whether small-scale locally endemic tree plantations are diverse habitats for
fauna (Brockerhoff et al. 2008). Fonseca et al. (2009) identify that when
monoculture plantations are managed ecologically, high species diversity can
result. This thesis provides evidence that with retained habitat features and in
close proximity to native forests monoculture native plantations can enhance
and extend native forests and can increase both local and regional diversity.
However, young native plantations offer few benefits for larger species of
ground fauna or forest-specialists, and support extra-regional species that
may negatively affect forested environments. How applicable these smallscale results are to plantations in forested environments generally is
uncertain, although the mechanisms identified as driving species responses
183
Chapter 7: General discussion
to plantations are not location-specific and are likely to apply in many
environments.
While management to enhance biodiversity at the stand level and
landscape levels is now employed in many commercial native plantations in
Australia, for the privately owned small-scale plantations that comprise more
than 8% the plantation estate such extra management aimed at specifically
increasing biodiversity is often too costly to implement (Alig 1998, Armsworth
et al. 2004). In commercial systems valuing native plantations as faunal
habitat and managing them as multi-use landscapes will incur some level of
economic cost in establishment, extra management, reduced timber
production and planning. Thus the decision to incorporate ecological
concepts into the planning, establishment and management of native
plantations must be undertaken with a mindfulness that the relative costs and
benefits of such extra expense will vary with the ecological context of the
plantations themselves. In the case where ecological management does not
supply great benefits to biodiversity, it may provide a better conservation
outcome to direct efforts and funding to other conservation measures.
184
References
References
ABARE, Pöyry, J., 1999. Forest Plantations on Cleared Agricultural Land in
Australia: A Regional Economic Analysis. In: ABARE (Ed.), Canberra,
Australia.
Adolph, S.C., 1990. Influence of behavioural thermoregulation on microhabitat
use by two Sceloporus lizards. Ecology Letters 71, 315-327.
Alexander, G.J., van der Heever, C., Lazenby, S.L., 2001. Thermal dependence
of appetite and digestive rate in the flat lizard, Platysaurus intermedius
wilhelmi. J. Herpetol. 35, 461-466.
Alig, R.J., Adams, D.M., McCarl, B.A., 1998. Ecological and economic impacts
of forest policies: interactions across forestry and agriculture. Ecological
Economics 27, 63-78.
Anderson, S.J., Death, R.G., 2000. The effect of forest type on forest floor
invertebrate community structure. New Zealand Natural Sciences 25, 3341.
Andersson, M., Krockenberger, A., Schwarzkopf, L., 2010. Experimental
manipulation reveals the importance of refuge habitat temperature
selected by lizards. Austral Ecol. 35, 294-299.
Angelici, F.M., Luiselli, L., Rugiero, L., 1997. Food habits of the green lizard,
Lacerta bilineata, in central Italy and a reliability test of faecal pellet
analysis. Ital. J. Zoolog. 64, 267-272.
Angilletta, M.J., Hill, T., Robson, M.A., 2002b. Is physiological performance
optimized by thermoregulatory behavior?: a case study of the eastern
fence lizard, Sceloporus undulatus. J. Therm. Biol. 27, 199-204.
Angilletta, M.J., Niewiarowski, P.H., Navas, C.A., 2002a. The evolution of
thermal physiology in ectotherms. J. Therm. Biol. 27, 249-268.
Archibald, R.D., Craig, M.D., Bialkowski, K., Howe, C., Burgess, T.I., Hardy,
G.E.S.J., 2011. Managing small remnants of native forest to increase
biodiversity within plantation landscapes in the south west of Western
Australia. For. Ecol. Man. 261, 1254-1264.
185
References
Armsworth, P.R., Kendall, B.E., Davis, F.W., 2004. An introduction to
biodiversity concepts for environmental economists. Resource and
Energy Economics 26, 115-136.
Arthur, A.D., Pech, R.P., Drew, A., Gifford, E., Henry, S., McKeown, A., 2003
The effect of increased ground-level habitat complexity on mouse
population dymanics. Wildl. Res. 30, 565-572.
Attum, O., Eason, P., Cobbs, G., El Din, S.M.B., 2006. Response of a desert
lizard community to habitat degradation: Do ideas about habitat
specialists/generalists hold? Biol. Cons. 133, 52-62.
Aubin, I., Messier, C., Bouchard, A., 2008. Can plantations develop understory
biological and physical attributes of naturally regenerated forests? Biol.
Cons. 141, 2461-2476.
Aubret, F., Shine, R., 2010. Thermal plasticity in young snakes: how will climate
change affect the thermoregulatory tactics of ectotherms? The Journal of
Experimental Biology 213, 242-248.
Australia, B., 1991-2007. Handbook of Australian, New Zealand and Antarctic
birds. Melbourne University Press.
Baas, S.F.J., Mennen, J.B.T., 1996. Aspects of microclimate in contrasting land
use, and the light climate along stream continuua in New Zealand.
National Institute of Water and Atmospheric Research Ltd, Hamilton, New
Zealand.
Baguette, M., Deceuninck, B., Muller, Y., 1994. Effects of spruce afforestation
on bird community dynamics in a native broad-leaved forest area. Acta
Oecologica 15, 275-288.
Bancroft, B.A., Baker, N.J., Searle, C.L., Garcia, T.S., Blaustein, A.R., 2008.
Larval amphibians seek warm temperatures and do not avoid harmful
UVB radiation. Behav. Ecol. 19, 879-886.
Barbaro, L., Pontcharraud, L., Vetillard, F., Guyon, D., Jactel, H., 2005.
Comparative responses of bird, carabid, and spider assemblages to
stand and landscape diversity in maritime pine plantation forests.
Ecoscience 12, 110-121.
186
References
Barbour, R.C., Potts, B.M., Vaillancourt, R.E., 2003. Gene flow between
introduced and native Eucalyptus species: exotic hybrids are establishing
in the wild. Australian Journal of Botany 51, 429-439.
Barker, J., Grigg, G.C., Tyler, M.J., 1995. A Filed Guide To Australian Frogs.
Surrey Beattie & Sons, Chipping Norton, NSW.
Barrientos, R., 2010. Retention of native vegetation within the plantation matrix
improves its conservation value for a generalist woodpecker. For. Ecol.
Man. 260, 595-602.
Battin, J., 2004. When good animals love bad habitats: Ecological traps and the
conservation of animal populations. Conserv. Biol. 18, 1482-1491.
Beaupre, S.J., Dunham, A.E., Overall, K.L., 1993. The effects of consumption
rate and temperature on apparent digestibility coefficient, urate production,
metabolizable energy coefficient and passage time in canyon lizards
(Sceleporus merriami) from two populations. . Funct. Ecol. 7, 273-280.
Becker, C.G., Joner, F., Fonesca, C.R., 2007. Ecologically-sustainable tree
monocultures contribute to conservation of a Araucaria Forest endemic
frog. J. Nat. Hist. 41, 1739-1752.
Beeton, R.J.S., Buckley, K.I., Jones, G.J., Morgan, D., Reichelt, R.E., Trewin, D.,
2006. Australia State of the Environment 2006.Department of the
Environment and Heritage, Canberra.
Beever, E.A., Brussard, P.F., 2004. Community- and landscape-level responses
of reptiles and small mammals to feral-horse grazing in the Great Basin. J.
Arid. Environ. 59, 271-297.
Belliure, J., Carrascal, L.M., 2002. Influence of heat transmission tode on
heating rates and on the selection of patches for heating in a
Mediterranean lizard. Physiol. Biochem. Zool. 75, 369-376.
Bengtsson, J., Nilsson, S.G., Franc, A., Menozzi, P., 2000. Biodiversity,
disturbances, ecosystem function and management of European forests.
For. Ecol. Man. 132, 39-50.
187
References
Bennett, A.F., 1998, 2003. Linkages in the Landscape: The role of Corridors and
Connectivity in Wildlife Conservation. IUCN, Gland, Switzerland and
Cambridge, UK, p. 245.
Bennett, A.F., John-Alder, H., 1986. Thermal relations of some Australian skinks
(Sauria:Scincidae). Copeia 1986, 57-64.
Bentley, J.M., Catterall, C.P., Smith, G.C., 2000. Effects of fragmentation of
Araucarian vine forest on small mammal communities. Conserv. Biol. 14,
1075-1087.
Bihn, J.H., Gebauer, G., Brandl, R., 2010. Loss of functional diversity of ant
assemblages in secondary tropical forests. Ecology 91, 782-792.
Bilcke, J., Downes, S., Buscher, I., 2006. Combined effect of incubation and
ambient temperature on the feeding performance of a small ectotherm.
Austral Ecol. 31, 937-947.
Bird, S.B., Coulson, R.N., Fisher, R.F., 2004. Changes in soil and litter arthropod
abundance following tree harvesting and site preparation in a loblolly pine
(Pinus taeda L.) plantation. For. Ecol. Man. 202, 195-208.
Blouin-Demers, G., Nadeau, P., 2005. The cost-benefit model of
thermoregulation does not predict lizard thermoregulatory behavior.
Ecology 86, 560-566.
Bonham, K.J., Mesibov, R., Bashford, R., 2002. Diversity and abundance of
some ground-dwelling invertebrates in plantation vs. native forest in
Tasmania, Australia. For. Ecol. Man. 158, 237-242.
Boone, R.B., Krohn, W.B., 2000. Partitioning sources of variation in vertebrate
species richness. J. Biogeogr. 27, 457-470.
Borenstein, Hedges, L.V., Higgins, J.P.T., Rothstein, H., 2009. Introduction to
Meta-analysis. John Wiley & Sons Ltd, West Sussex, UK.
Borsboom, A.C., Wang, J., Lees, N., Mathieson, M., Hogan, L., 2002.
Measurement and integration of fauna biodiversity values in Queensland
agroforestry systems. Rural Industries Research and Development
Corporation, Canberra.
188
References
Bos, D., Carthew, S.M., 2007. Prey selection by the dasyurid Ningaui yvonneae.
Wildl. Res. 34, 632-639.
Bowen, M.E., McAlpine, C.A., House, A.P.N., Smith, G.C., 2007. Regrowth
forests on abandoned agricultural land: A review of their habitat values for
recovering forest fauna. Biol. Cons. 140, 273-296.
Bremer, L.L., Farley, K.A., 2010. Does plantation forestry restore biodiversity or
create green deserts? A synthesis of the effects of land-use transitions on
plant species richness. Biodivers. Conserv. 19, 3893-3915.
Brockerhoff, E., Jactel, H., Parrotta, J., Ferraz, S.F.B., 2012. Role of eucalypt
and other planted forests in biodiversity conservation and the provision of
biodiversity-related ecosystem services. For. Ecol. Man. 301, 43-50.
Brockerhoff, E.G., Jactel, H., Parrotta, J.A., Quine, C.P., Sayer, J., 2008.
Plantation forests and biodiversity: oxymoron or opportunity? Biodivers.
Conserv. 17, 925-951.
Bromham, L., Cardillo, M., Bennett, A.F., Elgar., M.A., 1999. Effects of stock
grazing on the ground invertebrate fauna of woodland remnants. Aust. J.
Ecol. 24, 199-207.
Brown, G.W., 2001. The influence of habitat disturbance on reptiles in a
Box-Ironbark eucalypt forest of south-eastern Australia. Biodivers.
Conserv. 10, 161-176.
Brown, G.W., Bennett, A.F., Potts, J.M., 2008. Regional faunal decline – reptile
occurrence in fragmented rural landscapes of south-eastern Australia.
Wildl. Res. 35, 8-18.
Brown, G.W., Nelson, J.L., 1993. Influence of successional stage of Eucalyptus
regnans (mountain ash) on habitat use by reptiles in the central highlands.
Aust. J. Ecol. 18, 405-417.
Brown, R.D., Gillespie, T.J., 1995. Microclimatic Landscape Design. Wiley, New
York: New York.
189
References
Carey, A.B., Harrington, C.A., 2001. Small mammals in young forests:
implications for management and sustainability. For. Ecol. Man. 154, 289309.
Carlson, A., Groot, A., 1997. Microclimate of clear-cut, forest interior, and small
openings in trembling Aspen forest. Agric. For. Meteorol. 87, 313-329.
Carnus, J.M., Parrotta, J., Brockerhoff, E., Arbez, M., Jactel, H., Kremer, A.,
Lamb, D., O'Hara, K., Walters, B., 2006. Planted forests and biodiversity.
J. Forestry 104, 65-77.
Carrascal, L.M., Díaz, J.A., Huertas, D.L., Mozetich, I., 2001. Behavioural
thermoregulation by treecreepers: trade-off between saving energy and
reducing crypsis. Ecology 82, 1642-1654.
Carron, P.L., Happold, D.C.D., Bubela, T.M., 1990. Diet of 2 sympatric
Australian sub-alpine rodents, Mastacomys fuscus and Rattus fuscipes.
Aust. Wild. Res. 17, 479-489.
Caughley, J., 2001. Optimisation of zinc phosphide baiting to control mice.
Queensland Department of Natural Resources and Mines, Brisbane, QLD.
Cheal, D., 1987. The Diets and Dietary Preferences of Rattus fuscipes and
Rattus lutreolus at Walkerville in Victoria. Aust. Wild. Res. 14, 35-44.
Chen, J.Q., Franklin, J.F., 1997. Growing season microclimate variability within
an old-growth Douglas-fir forest. Climate Research 8, 21-34.
Chen, J.Q., Franklin, J.F., Spies, T.A., 1993. Contrasting microclimates among
clearcut, edge and interior of old-growth Douglas-fir forests. Agricultural
and Forest Meterology 63, 219-237.
Chen, J.Q., Franklin, J.F., Spies, T.A., 1995. Growing-season microclimatic
gradients from clear-cut edges into old-growth Douglas-fir forests. Ecol.
Appl. 5, 74-86.
Christian, D.P., Hoffman, W., Hanowski, J.M., Niemi, G.J., Beyea, J., 1998. Bird
and mammal diversity on woody biomass plantations in North America.
Biomass and Bioenergy 14, 395-402.
190
References
Christian, K.A., Bedford, G.S., Shannahan, S.T., 1996. Solar absorptance of
some Australian lizards and its relationship to temperature. Aust. J Zool.
44, 59-67.
Chruszcz, B.J., Barclay, R.M.R., 2002. Thermoregulatory ecology of a solitary
bat, Myotis evotis, roosting in rock crevices. Funct. Ecol. 16, 18-26.
Clapp, R.A., 2001. Tree framing and forest conservation in Chile: do
replacement forests leave any originals behind? Society and Natural
Resources 14, 341-356.
Clarke, K.R., 1993. Non-parametric multivariate analysis of changes in
community structure. Aust. J. Ecol. 18, 117-143.
Clinton, B.D., 2003. Light, temperature, and soil moisture responses to elevation,
evergreen understorey, and small canopy gaps in the southern
Appalachians. For. Ecol. Man. 186, 243-255.
Cogger, H.G., 1996. Reptiles and Amphibians of Australia. Reed Books,
Melbourne, Australia.
Coile, N.C., Shilling, D.G., 1993. Cogongrass, Imperata cylindrica( L) Beauv.: a
good grass gone bad. In, Botany Circular. Florida Department of
Agricultural Services, Florida, USA.
Costa, G.C., Vitt, L.J., Pianka, E.R., Mesquita, D.O., Colli, G.R., 2008. Optimal
foraging constrains macroecological patterns: body size and dietary niche
breadth in lizards. Glob. Ecol. Biogeogr. 17, 670-677.
Cowles, R., Bogert, C., 1944. A preliminary study of the thermal requirements of
desert reptiles. Iguana 83, 261-296.
Cox, P.G., Rayfield, E.J., Fagan, M.J., Herrel, A., Pataky, T.C., Jeffery, N., 2012.
Functional Evolution of the Feeding System in Rodents. PLoS One 7,
e36299.
Cummings, J., Reid, N., 2008. Stand-level management of plantations to
improve biodiversity values. Biodivers. Conserv. 17, 1187-1211.
Cunningham, R.B., Lindenmayer, D.B., Crane, M., Michael, D., Macgregor, C.,
2007. Reptile and arboreal marsupial response to replanted vegetation in
agricultural landscapes. Ecol. Appl. 17, 609-619.
191
References
Cunningham, S.A., Floyd, R.B., Weir, T.A., 2005. Do Eucalyptus plantations
host an insect community similar to remnant Eucalyptus forest? Austral
Ecol. 30, 103-117.
Cunningham, S.A., Murray, W., 2007. Average body length of arboreal and
aerial beetle (Coleoptera) assemblages from remnant and plantation
Eucalyptus forests in southwestern Australia. Oecologia 151, 303-312.
Curry, G.N., 1991. The influence of proximity to plantation edge on diversity and
abundance of bird species in an exotic pine plantation in North-eastern
New South Wales. Wildl. Res. 18, 299-314.
Dang, Q., Cheng, S., 2004. Effects of soil temperature on ecophysiological traits
in seedlings of four boreal tree species. For. Ecol. Man. 194, 379-387.
Davidson, N.J., Close, D.C., Battaglia, M., Churchill, K., Ottenschlaeger, M.,
Watson, T., Bruce, J., 2007. Eucalypt health and agricultural land
management within bushland remnants in the Midlands of Tasmania,
Australia. Biol. Cons. 139, 439-446.
Davis, A.J., Huijbregts, H., Krikken, J., 2000. The role of local and regional
precesses in shaping dung beetle communities in tropical forest
plantations in Borneo. Global Ecol. Biogeog. Letters 9, 281-292.
Delibes, M., Ferreras, P., Gaona, P., 2001. Attractive sinks, or how individual
behavioural decisions determine source—sink dynamics. Ecology Letters
4, 401-403.
Demidenko, E., 2004. Mixed Models: theory and applications. John WIley and
Sons, New Jersey, USA.
Dent, D.H., Wright, S.J., 2009. The future of tropical species in secondary
forests: A quantitative review. Biol. Cons. 142, 2833-2843.
Denyer, K., Burns, B., Ogden, J., 2006. Buffering of native forest edge
microclimate by adjoining tree plantations. Austral Ecol. 31, 478-489.
Devictor, V., Julliard, R., Jiguet, F., 2008. Distribution of specialist and generalist
species along spatial gradients of habitat disturbance and fragmentation.
Oikos 117, 507-514.
192
References
Díaz, J.A., 1995. Prey selection by lacertid lizards : A short review.
Herpetological Journal 5, 245-251.
Díaz, J.A., 1997. Ecological correlates of the thermal quality of an ectotherm's
habitat: A comparison between two temperate lizard populations. Funct.
Ecol. 11, 79-89.
Díaz, J.A., Cabezas-Díaz, Salvador, A., 2005. Seasonal changes in the thermal
envionrment do no affect microhabitat selsction by Psammodromus
algirus lizards. Herpetological Journal 15, 295-298.
Dickman, C.R., 1988. Body size, prey size and community structure in
insectivorous mammals. Ecology 69, 569-580.
Didham, R.K., Ghazoul, J., Stork, N.E., Davis, A.J., 1996. Insects in fragmented
forests: a functional approach. Trends in Ecology and Evolution 11, 255260.
do Nascimento, M.I., Poggiani, F., Durigan, G., Iemma, A.F., da Silva, D.F.,
2010. The effectiveness of Eucalyptus barrier in containing the edge
effect on a subtropical forest fragment in the state of Sao Paulo, Brazil.
Sci. For. 38, 191-203.
Dölle, M., Schmidt, W., 2009. Impact of tree species on nutrient and light
availability: evidence from a permanent plot study of old-field succession.
Plant Ecology 203, 273-287.
Downes, S., Shine, R., 1998. Heat, safety or solitude? Using habitat selection
experiments to identify a lizard's priorities. Anim. Behav. 55, 1387-1396.
Downes, S.J., Handasyde, K.A., Elgar, M.A., 1997. The use of corridors by
mammals in fragmented Australian eucalypt forests. Conserv. Biol. 11,
718-726.
Driscoll, D.A., 2004. Extinction and outbreaks accompany fragmentation of a
reptile community. Ecol. Appl. 14, 220-240.
Druzinsky, R.E., Greaves, W.S., 1979. A model to explain the posterior limit of
the bite point in reptiles. J. Morphol. 160, 165-168.
193
References
du Bus de Warnaffe, G., Dufrêne, M., 2004. To what extent can management
variables explain species assemblages? A study of carabid beetles in
forests. Ecography 27, 701-714.
Du, W.G., Shine, R., 2008. The influence of hydric environments during egg
incubation on embryonic heart rates and offspring phenotypes in a scincid
lizard (Lampropholis guichenoti). Comp. Biochem. Physiol. A-Mol. Integr.
Physiol. 151, 102-107.
Du, W.G., Yan, S.J., Ji, X., 2000. Selected body temperature, thermal tolerance
and thermal dependence of food assimilation and locomotor performance
in adult blue-tailed skinks, Eumeces elegans. J. Therm. Biol. 25, 197-202.
Dunham, A.E., Grant, B.W., Overall, K.L., 1989. Interactions between
biophysical and physiological ecology and the population ecology of
terrestrial vertebrate ectotherms. Physiol. Zool. 62, 335-355.
Dunn, R.R., 2004a. Managing tropical landscape : a comparison of the effects of
logging and forest conversion to agriculture on ants, birds and lepidoptera.
For. Ecol. Man. 191, 215-224.
Dunning, J.B., Danielson, B.J., Pulliam, H.R., 1992. Ecological processes that
affect populations in complex landscapes. Oikos 65, 169-175.
Durlak, J.A., 2009. How to select, calculate, and interpret effect sizes. Journal of
Pediatric Psychology 34, 917-928.
Ecke, F., Löfgren, O., Sörlin, D., 2002. Population dynamics of small mammals
in relation to forest age and sturctural habitat factors in northern Sweden.
J. Appl. Ecol. 39, 781-792.
Evans, A.R., Stanson, G.D., 2005. Biomechanical properties of insects in
relation to insectivory: cuticle thickness as an indicator of insect
'hardness' and 'intractability'. Australian Journal of Zoology 53, 9-19.
Evans, J., 1997. The sustainability of wood production in plantation forestry. XI
World Forestry Congress, Turkey.
194
References
Eyre, T., Kreiger, G., Vez, M., Haseler, M., Hines, B., Hannah, D., Schulz, M.,
1998. Systematic vertebrate fauna survey project: Stage 1. Department of
Environment, Brisbane, Australia.
FAO, 2010. Global Forest Resources Assessment 2010. Food and Agriculture
Organization of the United Nations, Rome.
FAO, 2011. State of the World's forests.Food and Agriculture Organization of
the United Nations, Rome.
FAO, 2006. Global planted forests thematic study: results and analysis. Planted
Forests and Tree Working Paper 38. Food and Agriculture Organization
of the United Nations, Rome.
Faria, D., Paciencia, M.L.B., Dixo, M., Laps, R.R., Baumgarten, J., 2007. Ferns,
frogs, lizards, birds and bats in forest fragments and shade cacao
plantations in two contrasting landscapes in the Atlantic forest, Brazil.
Biodivers. Conserv. 16, 2335-2357.
Farwig, N., Sajita, N., Bohning-Gaese, K., 2008. Conservation value of forest
plantations for bird communities in western Kenya. For. Ecol. Man. 255,
3885-3892.
Felton, A., Knight, E., Wood, J., Zammit, C., Lindenmayer, D., 2010. A
meta-analysis of fauna and flora species richness and abundance in
plantations and pasture lands. Biol. Cons. 143, 545-554.
Fischer, J., Lindenmayer, D.B., Cowling, A., 2004. The challenge of managing
multiple species at multiple scales: reptiles in an Australian grazing
landscape. J. Appl. Ecol. 41, 32-44.
Fischer, J., Lindenmayer, D.B., Manning, A.D., 2006. Biodiversity, ecosystem
function, and resilience: ten guiding principles for commodity production
landscapes. Frontiers in Ecology and the Environment 4, 80-86.
195
References
Fisher, A., Hunt, L., James, C., Landsberg, J., Phelps, D., Smyth, A., Watson, I.,
2004. Review of total grazing pressure management issues and priorities
for biodiversity conservation in rangelands: A resource to aid NRM
planning Project Report No. 3 (August 2004). Desert Knowledge CRC
and Tropical Savannas Management, Alice Springs.
Fisher, D.O., Dickman, C.R., 1993. Body size-prey size relationships in
insectivorous marsupials: Tests of 3 hypotheses Ecology 74, 1871-1883.
Fleishman, L.J., Bowman, M., Saunders, D., Miller, W.E., Rury, M.J., Loew, E.R.,
1997. The visual ecology of Puerto Rican anoline lizards: habitat light and
spectral sensitivity. J. Comp. Physiol. A-Sens. Neural Behav. Physiol. 181,
446-460.
Fletcher, H., 1977. Some habitat relations among small mammals at Petroi,
north-eastern New South Wales. In, Biological Sciences. New England, A
rmidale.
Florence, R.G., 1996. Ecology and Silviculture of Eucalypt Forests. CSIRO
Publishing, Melbourne: Australia.
Fonseca, C.R., Ganade, G., Baldissera, R., Becker, C.G., Boelter, C.R.,
Brescovit, A.D., Campos, L.M., Fleck, T., Fonseca, V.S., Hartz, S.M.,
Joner, F., Kaffer, M.I., Leal-Zanchet, A.M., Marcelli, M.P., Mesquita, A.S.,
Mondin, C.A., Paz, C.P., Petry, M.V., Piovensan, F.N., Putzke, J., Stranz,
A., Vergara, M., Vieira, E.M., 2009. Towards an ecologically-sustainable
forestry in the Atlantic Forest. Biol. Cons. 142, 1209-1219.
Forsman, A., 1996. Body size and net energy gain in gape-limited predators: A
model. J. Herpetol. 30, 307-319.
Fox, B.J., 1985. Small mammal communities in Australian temperate heathlands
and forests. Australian Mammalogy 8, 153-158.
Fredericksen, N.J., Fredericksen, T.S., 2002. Terrestrial wildlife responses to
logging and fire in a Bolivian tropical humid forest. Biodivers. Conserv. 11,
27-38.
196
References
Fretwell, S.D., Lucas, L.J., 1970. On territorial behavior and other factors
influencing habitat distribution in birds. Acta Biotheoretica 19, 16-36.
Gachet, S., Leduc, A., Bergeron, Y., Nguyen-Xuan, T., Tremblay, F., 2007.
Understory vegetation of boreal tree plantations: Differences in relation to
previous land use and natural forests. For. Ecol. Man. 242, 49-57.
Garcia-Barros, E., Benito, H.R., 2010. The relationship between geographic
range size and life history traits: is biogeographic history uncovered? A
test using the Iberian butterflies. Ecography 33, 392-401.
Garden, J.G., McAlpine, C.A., Possingham, H.P., Jones, D.N., 2007. Habitat
structure is more important than vegetation composition for local-level
management of native terrestrial reptile and small mammal species living
in urban remnants: A case study from Brisbane, Australia. Austral Ecol.
32, 669-385.
Gardner, T.A., Barlow, J., Peres, C.A., 2007a. Paradox, presumption and pitfalls
in conservation biology: The importance of habitat change for amphibians
and reptiles. Biol. Cons. 138, 166-179.
Gardner, T.A., Ribeiro-Junior, M.A., Barlow, J., Cristina, T., Avila-Pires, S.,
Hoogmoed, M.S., Peres, C.A., 2007b. The value of primary, secondary,
and plantation forests for a neotropical herpetofauna Conserv. Biol. 21,
775-787.
Gascon, C., Lovejoy, T.E., Bierregaard Jr, R.O., Malcolm, J.R., Stouffer, P.C.,
Vasconcelos, H.L., William F. Laurance, Zimmerman, B., Tocher, M.,
Borges, S., 1999. Matrix habitat and species richness in tropical forest
remnants. Biol. Cons. 91, 223-229.
Gavran, M., 2013. Australian plantation statistics 2013 update. ABARES
technical report 13.3, Canberra, May. CC BY 3.0.
Gibbons, J.W., Scott, D.E., Ryan, T.J., Buhlmann, K.A., Tuberville, T.D., Metts,
B.S., Greene, J.L., Mills, T., Leiden, Y., Poppy, S., Winne, C.T., 2000.
The global decline of reptiles, déjà vu amphibians. Bioscience 50, 653666.
197
References
Gill, A.M., 1981. Adaptive response of Australian vascular plant species to fire.
In: Gill, A.M., Groves, R.H., Noble, I.R. (Eds.), Fire and the Australian
Biota. Australian Academy of Science, Canberra, pp. 234-269.
Gjerde, I., Sætersdal, M., 1997. Effects on avian diversity of introducing spruce
Picea spp. plantations in the native pine Pinus sylvestris forests of
western Norway. Biol. Cons. 79, 241-250.
Gliner, J.A., Morgan, G.A., Harmon, R.J., 2003. Meta-analysis: formulation and
interpretation. Journal of the American Academy of Child and Adolescent
Psychiatry 42, 1376-1379.
Goldsbrough, C.L., Shine, R., Hochuli, D.F., 2006. Factors affecting retreat-site
selection by coppertail skinks (Ctenotus taeniolatus) from sandstone
outcrops in eastern Australia. Austral Ecol. 31, 326-336.
Grant, B.W., Dunham, A.E., 1988. Thermally imposed time constraints on the
activity of the desert lizard Sceloporus merriami. Ecology 69, 167-176.
Green, K., 1989. Altitudinal and seasonal differences in the diets of Antechinus
swainsonii and A. stuartii (Marsupialia : Dasyuridae) in relation to the
availability of prey in the Snowy Mountains. Aust. Wild. Res. 16, 581-592.
Green, R.J., Catterall, C.P., 1998. The effects of forest clearing and
regeneration on the fauna of Wivenhoe Park, south-east Queensland.
Wildl. Res. 25, 677-690.
Greenville, A.C., Dickman, C.R., 2009. Factors affecting habitat selection in a
specialist fossorial skink. Biological Journal of the Linnean Society 97,
531-544.
Greer, A.E., 1980. Critical Thermal Maximum Temperatures in Australian
Scincid Lizards: Their Ecological and Evolutionary Significance. .
Australian Journal of Zoology 28, 91-102.
Greer, A.E., 2005. Encyclopedia of Australian Reptiles. Australian Museum
Online. in Greer, A.E. (Ed.), Encyclopedia of Australian Reptiles. .
Australian Museum Online, Sydney.
198
References
Gries, R., Louzada, J., Almeida, S., Macedo, R., Barlow, J., 2012. Evaluating the
impacts and conservation value of exotic and native tree afforestation in
Cerrado grasslands using dung beetles. Insect. Conserv. Divers. 5, 175185.
Grimbacher, P.S., Catterall, C.P., Kanowski, J., Proctor, H.C., 2007. Responses
of ground-active beetle assemblages to different styles of reforestation on
cleared rainforest land. Biodivers. Conserv. 16, 2167-2184.
Gullison, R.E., 2003. Does forest certification conserve biodiversity? Orxy 37,
513-165.
Halverson, M.A., Skelly, D.K., Kiesecker, J.M., Freidenburg, L.K., 2003. Forest
mediated light regime linked to amphibian distribution and performance.
Oecologia 134, 360-364.
Hanley, T.A., 2005. Potential management of young-growth stands for
understory vegetation and wildlife habitat in southeastern Alaska. Land.
Urb. Plan. 72, 95-112.
Hansen, A.J., McComb, W.C., Vega, R., Raphael, M.G., Hunter, M., 1995. Bird
habitat relationships in natural and managed forests in the west
Cascades of Oregon. Ecol. Appl. 5, 555-569.
Hanson, T.R., Newmark, W.D., Stanley, W.T., 2007. Forest fragmentation and
predation on artificial nests in the Usambara Mountains, Tanzania. Afr. J.
Ecol. 45, 499-507.
Harden, G.J., 1991. Flora of New South Wales. Volume 2. New South Wales
University Press, Kensington, New South Wales, Australia.
Harlow, H.J., Hillman, S.S., Hoffman, M., 1976. The effect of digestive efficiency
in the herbivorous lizard Dipsosaurus dorsalis. J. Comp. Physiol. BBiochem. Syst. Environ. Physiol. 111, 1-6.
Hartley, M.J., 2002. Rationale and methods for conserving biodiversity in
plantation forests. For. Ecol. Man. 155, 81-95.
Hartmann, H., Daoust, G., Bigue, B., Messier, C., 2010. Negative or positive
effects of plantation and intensive forestry on biodiversity: A matter of
scale and perspective. For. Chron., 86, 354-364.
199
References
Heatwole, H., 1977. Habitat selection in reptiles. Academic Press, New York,
New York, USA.
Heatwole, H., Taylor, J., 1987. Ecology of Reptiles. Surrey Beatty & Sons Pty
Ltd, Chipping Norton, NSW.
Hedges, L.V., Olkin, I., 1985. Statistical Methods For Meta-Analysis. In.
Academic Press, Orlando, Flroida, USA.
Henle, K., Davies, K.F., Kleyer, M., Margules, C., Settele, J., 2004. Predictors of
species sensitivities to fragmentation. Biodivers. Conserv. 13, 207-251.
Henríquez, P., Donoso, D.S., Grez, A.A., 2009. Population density, sex ratio,
body size and fluctuating asymmetry of Ceroglossus chilensis (Carabidae)
in the fragmented Maulino forest and surrounding pine plantations. Acta
Oecol.-Int. J. Ecol. 35, 811-818.
Herrel, A., De Vree, F., 2009. Jaw and hyolingual muscle activity patterns and
bite forces in the herbivorous lizard Uromastyx acanthinurus. Arch. Oral
Biol. 54, 772-782.
Herrel, A., Schaerlaeken, V., Meyers, J.J., Metzgerz, K.A., Ross, C.F., 2007.
The evolution of cranial design and performance in squamates:
Consequences of skull-bone reduction on feeding behavior. In, The
Evolution of Feeding Mechanisms in Vertebrates. Society for Integrative
and Comparirtive Biology, Phoenix, Arizona, USA, pp. 107-117.
Herrel, A., Van Damme, R., Vanhooydonck, B., De Vree, F., 2001. The
implications of bite performance for diet in two species of lacertid lizards.
Can. J. Zool.-Rev. Can. Zool. 79, 662-670.
Hertz, P.E., Fleishman, L.J., Armsby, C., 1994. The influence of light-intensity
and temperature on microhabitat selection in Anolis lizards. Funct. Ecol. 8,
720-729.
Hill, R.A., 2006. Thermal constraints on activity scheduling and habitat choice in
baboons. American Journal of Physical Anthropology 129, 242-249.
Hjelm, M., Persson, L., 2001. Size-dependent attack rate and handling capacity:
inter-cohort competition in a zooplanktivorous fish. Oikos 95, 520-532.
200
References
Hoare, J.M., O'Donnell, C.F.J., Westbrooke, I., Hodapp, D., Lettink, M., 2009.
Optimising the sampling of skinks using artificial retreats based on
weather conditions and time of day. Appl. Herpetol. 6, 379-390.
Hobbs, R.J., Catling, P.C., Wombey, J.C., Clayton, M., Atkins, L., Reid, A., 2003.
Faunal use of bluegum (Eucalyptus globulus) plantations in southwestern
Australia. Agrofor. Syst. 58, 195-212.
Hobbs, R.J., Floyd, R., Cunningham, S., Catling, P., Ive, J., 2003b. Hardwood
Plantations: Quantifying conservation and environmental service benefits.
Rural Industries Research and Development Corporation, Canberra: ACT.
Hochacha, P.W., Somero, G.N., 1984. Biochemical Adaptation. Princeton
University Press, Princeton, NJ.
Hochachka, W.M., Caruna, R., Fink, D., Munson, A., Riedewald, M., Sorokina, D.
Kelling, S., 2007. Data-mining discovery of pattern and process in
ecological systems. J. Wildl. Manage. 71, 2427-2437.
Hodge, S., Marshall, S.A., Oliver, H., Berry, J., Marris, J., Andrew, I., 2010. A
preliminary survey of the insects collected using mushroom baits in native
and exotic New Zealand woodlands. N. Z. Entomol. 33, 43-54.
Hodgkison, S.C., Hero, J.-M., 2003. Seasonal, sexual and ontogenetic variations
in the diet of the declining frogs, Litoria nannotis, L. rheocola and
Nyctimystes dayi Wildl. Res. 30, 345-354.
Holl, K.D., 1999. Factors limiting tropical rainforest regeneration in abandoned
pasture: Seed rain, seed germination, microclimate, and soil. Biotropica
31, 229-242.
Holland, G.J., Bennett, A.F., 2007. Occurrence of small mammals in a
fragmented landscape: the role of vegetation heterogeneity. Wildl. Res.
34, 387-397.
Homyack, J.A., 2010. Evaluating habitat quality of vertebrates using
conservation physiology tools. Wildl. Res. 37, 332-342.
Homyack, J.A., Harrison, D.J., Krohn, W.B., 2005. Long-term effects of
precommercial thinning on small mammals in northern Maine. For. Ecol.
Man. 205, 43-57.
201
References
Honkavaara, J., Koivula, M., Korpima¨ki, E., Siitari, H., Viitala, J., 2002.
Ultraviolet vision and foraging in terrestrial vertebrates. Oikos 98, 505-511.
Hsu, T.N., French, K., Major, R., 2010. Avian assemblages in eucalypt forests,
plantations and pastures in northern NSW, Australia. For. Ecol. Man. 260,
1036-1046.
Huey, R.B., 1982. Temperature, physiology, and the ecology of reptiles. In:
Gans, C., Pough, F.H. (Eds.), Biology of the Reptilia. Academic Press,
New York, USA, pp. 25-91.
Huey, R.B., 1991. Physiological Consequences of Habitat Selection. The
American Naturalist 137, S91-S115.
Huey, R.B., Bennett, A.F., 1987. Phylogenetic studies of coadaptation: preferred
temperatures versus optimal performance temperatures of lizards.
Evolution 41, 1098-1115.
Huey, R.B., Slatkin, M., 1976. Costs and benefits of lizard thermoregulation. The
Quarterly Review of Biology 51, 363-384.
Humphrey, J.W., Hawes, C., Peace, A.J., Ferris-Kaan, R., Jukes, M.R., 1999.
Relationships between insect diversity and habitat characteristics in
plantation forests. For. Ecol. Man. 113, 11-21.
Hunter, M.D., Forkner, R.E., McNeil, J.N., 2000. Heterogeneity in plant quality
and its impact on the population ecology of insect herbivores. In: Hutchins,
M.A., John, E.A., Stewart, A.J.A. (Eds.), The Ecological Consequences of
Environmental Heterogeneity. Blackwell Science, Oxford.
Hunter, M.L.J., 1990. Wildlife, Forests, and Forestry: Principles of Managing
Forests for Biological Diversity. Prentice Hall, New Jersey.
Hutchinson, M.N., 1993. Family Scincidae. pp. 261-279. In: Glasby, C.J., Ross,
G.J.B., Beesley, P.L. (Eds.), Fauna of Australia. Vol. 2A Amphibia &
Reptilia. Australian Government Publishing Service, Canberra, pp. 261279.
Hutchison, V.H., Maness, J.D., 1979. Role of behavior in temperatureacclimation and tolerance in ectotherms. American Zoologist 19, 367-384.
202
References
Issac, J.L., De Gabriel, J.L., Goodman, B.A., 2008. Microclimate of daytime den
sites in a tropical possum: implications for the conservation of tropical
arboreal marsupials. Animal Conservation 11, 281-287.
Ito, S., Nakayama, R., Buckley, G.P., 2004. Effects of previous land-use on plant
species diversity in semi-natural and plantation forests in a warmtemperate region in southeastern Kyushu, Japan. For. Ecol. Man. 196,
213-225.
James, C., 2003. Response of vertebrates to fenceline contrasts in grazing
intensity in semi-arid woodlands of eastern Australia. Austral Ecol. 28,
137-151.
James, C.D., 1994. Spatial and temporal variation in a structure of a diverse
lizard assemblage in arid Australia. In: Vitt, L.J., Pianka, E.R. (Eds.),
Lizard Ecology. Hisotrical and Experimental Perspectives. Princeton
University Press, Princeton, New Jersey, pp. 287-317.
Jelaska, L.S., Dumbović, V., Kučinić, M., 2011. Carabid beetle diversity and
mean individual biomass in beech forests of various ages. ZooKeys 100,
393-405.
Jenkins, R.K.B., Roettcher, K., Corti, G., 2003. The influence of stand age on
wildlife habitat use in exotic Teak tree Tectona grandis plantations.
Biodivers. Conserv. 12, 975-990.
Johnson, R., Ferguson, J.W.H., van Jaarsveld, A.S., Bronner, G.N., Chimimba,
C.T., 2002. Delayed responses of small-mammal assemblages subject to
afforestation-induced grassland fragmentation. Journal of Mammalogy 83,
290-300.
Kanowski, J., Catterall, C.P., Wardell-Johnson, G.W., 2005. Consequences of
broadscale timber plantations for biodiversity in cleared rainforest
landscapes of tropical and subtropical Australia. For. Ecol. Man. 208,
359-372.
203
References
Kanowski, J., Catterall, C.P., Wardell-Johnson, G.W., Proctor, H., Reis, T., 2003.
Development of forest structure on cleared rainforest land in eastern
Australia under different styles of reforestation. For. Ecol. Man. 183, 265280.
Kanowski, J.J., Reis, T.M., Catterall, C.P., Piper, S.D., 2006. Factors affecting
the use of reforested sites by reptiles in cleared rainforest landscapes in
tropical and subtropical Australia. Restor. Ecol. 14, 67-76.
Kanowski, P.J., 1997. Afforestation and plantation forestry :plantations forestry
for the 21st century. In, XI World Forestry Congress, Turkey.
Kanowski, P.J., Savill, P.S., Adlard, P.G., Burley, J., Evans, J., Palmer, J.R.,
Wood, P.J., 1992. Plantation Forestry. In: Sharma, N.P. (Ed.), Managing
the World's Forests. Kendall/Hunt Publishing Company, Iowa, USA, pp.
375-401.
Kavanagh, R., Law, B., Lemckert, F., Stanton, M., Chidel, M., Towerton, A.,
2001. Birds, mammals, reptiles and amphibians in eucalypt plantations
near Albury-Wodonga: A pilot study of variables influencing biodiversity.
In. State Forests of New South Wales, Beecroft, New South Wales,
Australia.
Kavanagh, R., Law, B.S., Lemckert, F., Stanton, M., Chidel, M., Brassil, T.,
Towerton, A., Herring, M.W., 2005. Biodiversity in eucalypt plantings
established to reduce salinity. In. Rural Industries Research and
Development Corporation, Canberra, pp. 1-81.
Kavanagh, R., Stanton, M.A., 2005. Vertebrate species assemblages and
species sensitivity to logging in the forests of north-eastern New South
Wales. For. Ecol. Man. 209, 309-341.
Keenan, R., Lamb, D., Woldring, O., Irvine, T., Jensen, R., 1997. Restoration of
plant biodiversity beneath tropical tree plantations in Northern Australia.
For. Ecol. Man. 99, 117-131.
Kelly, C.K., Chase, M.W., Bruijn, A.d., Fay, M.F., Woodward, F.I., 2003.
Temperature-based population segregation in birch. Ecology Letters 6,
87-89.
204
References
Kerr, G., 1999. The use of silvicultural systems to enhance the biological
diversity of plantation forests in Britain. Forestry 72, 191-205.
Klomp, N., Grabham, C., 2002. A comparison of the avifaunal diversity on native
hardwood plantations and pastureland in north-east Victoria 1999-2001.
Johnstone Centre Report No. 164,Charles Sturt University, Albury, NSW.
Kluber, M.R., Olson, D.H., Puettmann, K.J., 2009. Downed wood microclimates
and their potential impact on Plethodontid salamander habitat in the
Oregon coast range. Northwest Sci. 83, 25-34.
Knops, J.M.H., Tilman, D., Haddad, N.M., Shahid, N., Mitchell, C.E., Haarstad, J.
Ritchie, M.E., Howe, K.M., Reich, P.B., Siemann, E., Groth, J., 1999.
Effects of plant species richness on invasion dynamics, disease
outbreaks, insect abundances and diversity. Ecology Letters 2, 286-293.
Kopper, K.E., McKenzie, D., Peterson, D.L., 2009. The evaluation of
meta-analysis techniques for quantifying prescribed fire effects on fuel
loadings. U.S. Department of Agriculture, F.S., Pacific Northwest
Research Station, Portland, Oregon, p. 24.
Kotzen, B., 2003. An investigation of shade under six different tree species of
the Negev desert towards their potential use for enhancing micro-climatic
conditions in landscape architectural development. J. Arid. Environ. 55,
231-274.
Kozlowskia, T.T., 1999. Soil Compaction and Growth of Woody Plants.
Scandinavian Journal of Forest Research 14, 596-619.
Kufs, C., 2011. Stats with Cats: The Domesticated Guide to Statistics, Models,
Graphs, and Other Breeds of Data Analysis Wheatmark, Arizona, USA.
Kupfer, J.A., Malanson, G.P., Franklin, S.B., 2006. Not seeing the ocean for the
islands: the mediating influence of matrix-based processes on forest
fragmentation effects. Glob. Ecol. Biogeogr. 15, 8-20.
Kutt, A.S., Woinarski, J.C.Z., 2007. The effects of grazing and fire on vegetation
and the vertebrate assemblage in a tropical savanna woodland in northeastern Australia J. Trop. Ecol. 23, 95-106.
205
References
Lagos, V.E., Bozinovic, F., L.C.Contreras, 1995. Microhabitat use by a small
diurnal rodent (Octodon degus) in a semiarid environment:
thermoregulatory constraints or predation risk? Journal of Mammalogy 76,
900-905.
Lajeunesse, M.J., Forbes, M.R., 2003. Variable reporting and quantitative
reviews: a comparison of three meta-analytical techniques. Ecology
Letters 6, 448-454.
Laparie, M., Lebouvier, M., Lalouette, L., Renault, D., 2010. Variation of
morphometric traits in populations of an invasive carabid predator
(Merizodus soledadinus) within a sub-Antarctic island. Biol. Invasions 12,
3405-3417.
Laurance, W.F., 2004. Forest-climate interactions in fragmented tropical
landscapes. Philosophical Transactions of the Royal Society of London:
Biological Sciences 359, 345-352.
Laurance, W.F., Dell, B., Turton, S.M., Lawes, M.J., Hutley, L.B., McCallum, H.,
Dale, P., Bird, M., Hardy, G., Prideaux, G., Gawne, B., McMahon, C.R.,
Yu, R., Hero, J.M., Schwarzkop, L., Krockenberger, A., Douglas, M.,
Silvester, E., Mahony, M., Vella, K., Saikia, U., Wahren, C.H., Xu, Z.H.,
Smith, B., Cocklin, C., 2011. The 10 Australian ecosystems most
vulnerable to tipping points. Biol. Cons. 144, 1472-1480.
Law, B., Chidel, M., 2002. Small mammals in remnant vegetation, cleared
paddocks and young Eucalyptus plantations. Ecological Management
and Restoration 3, 64-66.
Lawler, J.J., Shafer, S.L., White, D., Kareiva, P., Maurer, E.P., Blaustein, A.R.,
Bartlein, P.J., 2009. Projected climate-induced faunal change in the
Western Hemisphere. Ecology 90, 588-597.
Lawton, J.H., Bignell, D.E., Bolton, B., Bloemers, G.F., Eggleton, P., Hammond,
P.M., Hodda, M., Holt, R.D., Larsen, T.B., Mawdsley, N.A., Stork, N.E.,
Srivastava, D.S., Watt, A.D., 1998. Biodiversity inventories, indicator taxa
and effects of habitat modification in tropical forest. Nature 391, 72-76.
206
References
Leal, M., Fleishman, L.J., 2004. Differences in visual signal design and
detectability between allopatric populations of Anolis lizards. Am. Nat.
163, 26-39.
Leite, F.P., Silva, I.R., Novais, R.F., de Barros, N.F., Neves, J.C.L., 2010.
Alterations of soil chemical properties by eucalyptus cultivation in five
regions in the Rio Doce valley. Rev. Bras. Cienc. Solo 34, 821-831.
Lemenih, M., Gidyelew, T., Teketay, D., 2004. Effects of canopy cover and
understorey environment of tree plantations on richness, density and size
of colonizing woody species in southern Ethiopia. For. Ecol. Man. 194, 110.
Lescroёl, A., Ballard, G., Toniolo, V., Barton, K.J., Wilson, P.R., Lyver, P.O.,
Ainley, D.G., 2010. Working less to gain more: when breeding quality
relates to foraging efficiency. Ecology 91, 2044-2055.
Lima, A.P., Magnusson, W.E., Williams, D.G., 2000. Differences in diet among
frogs and lizards coexisting in subtropical forests of Australia. J. Herpetol.
34, 40-46.
Lindenmayer, D.B., Cunningham, R.B., Pope, M.L., 1999. A large-scale
"experiment" to examine the effects of landscape context and habitat
fragmentation on mammals. Biol. Cons. 88, 387-403.
Lindenmayer, D.B., Franklin, J.F., 2002. Conserving Forest Biodiversity: a
comprehensive multiscaled approach. Island Press, Washington: America.
Lindenmayer, D.B., Hobbs, R.J., 2004. Fauna conservation in Australian
plantation forests - a review. Biol. Cons. 119, 151-168.
Lindenmayer, D.B., McCarthy, M.A., Parris, K.M., Pope, M.L., 2000. Habitat
fragmentation, landscape context, and mammalian assemblages in
southeastern Australia. Journal of Mammalogy 81, 787-797.
Lindenmayer, D.B., McIntyre, S., Fischer, J., 2003. Birds in eucalypt and pine
forests: landscape alteration and its implications for research models of
faunal habitat use. Biol. Cons. 110, 45-53.
207
References
Lindenmayer, D.B., Wood, J.T., Cunningham, R.B., Crane, M., Macgregor, C.,
Michael, D., Montague-Drake, R., 2009. Experimental evidence of the
effects of a changed matrix on conserving biodiversity within patches of
native forest in an industrial plantation landscape. Landsc. Ecol. 24,
1091-1103.
Lipsey, M.W., Wilson, D.B., 2001. Practical Meta-Analysis. Sage Publications,
California, USA.
Loeb, S.C., 1999. Responses of small mammals to coarse woody debris in a
southeastern pine forest. Journal of Mammalogy 80, 460-471.
Loehle, C., Wigley, T.B., Rutzmoser, S., Gerwin, J.A., Keyser, P.D., Lancia, R.A.,
Reynolds, C.J., Thill, R.E., Weih, R., Jr., D.W., Wood, P.B., 2005.
Managed forest landscape structure and avian species richness in the
southeastern US. For. Ecol. Man. 214, 279-293.
Loyn, R.H., McNabb, E.G., Macak, P., Cheers, G., 2009. Fauna in eucalypt and
pine plantations in the Green Triangle of South-eastern South Australia
and south-western Victoria. Arthur Rylah Institute for Environmental
Research Technical Report Series 186. Department of Sustainability and
Environment, Canberra.
Loyn, R.H., McNabb, E.G., Macak, P., Noble, P., 2008. Eucalypt plantation
habitats for fauna in rural landscapes: Enhancing their value with
appropriate designs. In. Rural Industries Research and Development
Corporation, Barton, ACT.
Loyn, R.H., McNabb, E.G., Phoebe, M., Noble, P., 2007. Eucalypt planations as
habitat for birds on previously cleared farmland in south-eastern Australia.
Biol. Cons. 137, 533-548.
Luck, G.W., Daily, G.C., Ehrlich, P.R., 2003. Population diversity and ecosystem
services. Trends Ecol. Evol. 18, 331-336.
Lunney, D., Ashby, E., Grigg, J., Oconnell, M., 1989. Diets of scincid lizards
Lampropholis guichenoti (Dumeril and Bibron) and Lampropholis delicata
(De Vis) in Mumbulla State Forest on the south coast of New South
Wales. Aust. Wild. Res. 16, 307-312.
208
References
Lunney, D., Matthews, A., Grigg, J., 2001. The diet of Antechinus agilis and A.
swainsonii in unlogged and regenerating sites in Mumbulla State Forest,
south-eastern New South Wales. Wildl. Res. 28, 459-464.
Mac Nally, R., Parkinson, A., Horrocks, G., Conole, L., Tzaros, C., 2001.
Relationships between terrestrial vertebrate diversity, abundance and
availability of coarse woody debris on south-eastern Australian
floodplains. Biol. Cons. 99, 191-205.
MacArthur, R.H., MacArthur, J.W., Preer, J., 1962. On bird species diversity. II.
Prediction of bird census from habitat measurements. Am. Nat. 96, 167174.
MacDonald, G.B., Thompson, D.J., 2003. Responses of planted conifers and
natural hardwood regeneration to harvesting, scalping, and weeding on a
boreal mixedwood site. For. Ecol. Man. 182, 213-230.
Magnuson, J.J., Crowder, L.B., Medvick, P.A., 1979. Temperature as an
ecological resource. American Zoologist 19, 331-343.
Maitz, W.E., Dickman, C.R., 2001. Competition and habitat use in native
Australian Rattus: is competition intense, or important? Oecologia 128,
526-538.
Malcom, J.R., 1998. A model of conductive heat flow in forest edges and
fragmented landscapes. Climate Change 39, 487-502.
Marchesan, D., Carthew, S.M., 2008. Use of space by the Yellow-footed
Antechinus, Antechinus flavipes, in a fragmented landscape in South
Australia. Landsc. Ecol. 23, 741-752.
Marcos, J.A., Marcos, E., Taboada, A., Tárrega, R., 2007. Comparison of
community structure and soil characteristics in different aged Pinus
sylvestris plantations and a natural pine forest. For. Ecol. Man. 247, 3542.
Marín-Martínez, F., Sánchez-Meca, J., 1999. Averaging dependent effect sizes
in meta-analysis: a cautionary note about procedures. The Spanish
Journal of Psychology 2, 32-38.
209
References
Martín, J., López, P., 2010. Thermal constraints of refuge use by Schreiber's
green lizards, Lacerta schreiberi. Behaviour 147, 275-284.
Martin, T.E., 2001. Abiotic vs. biotic influences on habitat selection of coexisting
species: climate change impacts? Ecology 82, 175-188.
Martin, T.L., Huey, R.B., 2008. Why "Suboptimal" is optimal: Jensen's inequality
and ectotherm thermal preferences. Am. Nat. 171, E102-E118.
Martius, C., Hofer, H., Garcia, M.V.B., Rombke, J., Forster, B., Hanagarth, W.,
2004. Microclimate in agroforestry systems in central Amazonia: does
canopy closure matter to soil organisms? Agrofor. Syst. 60, 291-304.
Mason, T.J., French, K., Lonsdale, W.M., 2009. Do graminoid and woody
invaders have different effects in native plant functional groups? J. Appl.
Ecol. 46, 426-433.
Mayr, E., 1963. Animal Species and Evolution. Belknap, Cambridge, MA.
McConnachie, S., Alexander, G.J., 2004. The effect of temperature on digestive
and assimilation efficiency, gut passage time and appetite in an ambush
foraging lizard, Cordylus melanotus melanotus. J. Comp. Physiol. BBiochem. Syst. Environ. Physiol. 174, 99-105.
McCullough, R.B., 1999. Four common myths about plantation forestry. New For.
17, 111-118.
McDonald, R.C., Isbell, R.F., Speight, J.G., Walker, J., Hopkins, M.S., 1990.
Australian soil and land survey field handbook. Inkata Press, Sydney.
McIntyre, S., Hobbs, R., 1999. A framework for conceptualizing human effects
on landscapes and its relevance to management and research models.
Conserv. Biol. 13, 1282-1292.
Mengak, M.T., Guyunn Jr., D.C., 2003. Small mammal microhabitat use on
young loblolly pine regeneration areas. For. Ecol. Man. 173, 309-317.
Mercer, D., Underwood, A., 2002. Australian timber plantations: national vision,
local response. Land Use Policy 19, 107-122.
Messier, C., Parent, S., Bergeron, Y., 1998. Effects of overstory and understory
vegetation on the understory light environment in mixed boreal forests. J.
Veg. Sci. 9, 511-520.
210
References
Michael, D.R., Cunningham, R.B., Lindenmayer, D.B., 2010. Microhabitat
relationships among five lizard species associated with granite outcrops
in fragmented agricultural landscapes of south-eastern Australia. Austral
Ecol. 35, 215-226.
Mitchell, M.S., Karriker, K.S., Jones, E.J., Lancia, R.A., 1995. Small mammal
communities associated with pine plantation management of pocosins. J.
Wildl. Manage. 59, 875-881.
Moore, S.E., Allen, L., 1999. Plantation Forestry. In: Hunter, M.L.J. (Ed.),
Maintaining Biodiversity in Forest Ecosystems. Cambridge University
Press, Cambridge: England, pp. 400-433.
Morecroft, M.D., M.E.Taylor, Oliver, H.R., 1998. Air and soil microclimates of a
deciduous woodland compared to an open site. Agric. For. Meteorol. 90,
141-156.
Moser, B.W., Pipas, M.J., Witmer, G.W., Engeman, R.M., 2002. Small mammal
use of hybrid poplar plantations relative to stand age. Northwest Sci. 76,
158-165.
Mott, B., Alford, R.A., Schwarzkopf, L., 2010. Tropical reptiles in pine forests:
Assemblage responses to plantations and plantation management by
burning. For. Ecol. Man. 259, 916-925.
Munro, N.T., Fischer, J., Wood, J., Lindenmayer, D.B., 2009. Revegetation in
agricultural areas: the development of structural complexity and floristic
diversity. Ecol. Appl. 19, 1197-1210.
Munro, N.T., Lindenmayer, D.B., Fischer, J., 2007. Faunal response to
revegetation in agricultural areas of Australia: A review. Ecological
Management and Restoration 8, 199-207.
Nájera, A., Simonetti, J.A., 2010. Enhancing Avifauna in Commercial Plantations.
Conserv. Biol. 24, 319-324.
Neumann, D.D., 1991. Responses of litter arthropods to major natural or artificial
ecological disturbances in mountain ash forest. Aust. J. Ecol. 16, 19-32.
211
References
Novak, M.D., Warland, J.S., Orchansky, A.L., Ketler, R., Green, S., 2000. Wind
tunnel and field measurements of turbulent flow in forests. Part I:
uniformly thinned stands. Boundary-layer Meterology 95, 457-495.
NPWS, 2001. Atlas of New South Wales wildlife. NSW National Parks and
Wildlife Service, Hurstville, NSW.
O'Connor, D., Moritz, C., 2003. A molecular phylogeny of the Australian skink
genera Eulamprus, Gnypetoscincus and Nangura. Australian Journal of
Zoology 51, 317-330.
Ojanguren, A.F., Reyes-Gavilán, F.G., Braña, F., 2001. Thermal sensitivity of
growth, food intake and activity of juvenile brown trout. J. Therm. Biol. 26,
165-170.
Osenberg, C.W., Sarnelle, O., Cooper, S.D., 1997. Effect size in ecological
experiments: The application of biological models to meta-analysis. Am.
Nat. 150, 798-812.
Ouedraogo, R.M., Goettel, M.S., Brodeur, J., 2004. Behavioural
thermoregulation in a migratory locust: therapy to overcome fungal
infection. Oecologia 138, 312-319.
Owens, A.K., Moseley, K.R., McCay, T.S., Castleberry, S.B., Kilgo, J.C., Ford,
W.M., 2008. Amphibian and reptile community response to coarse woody
debris manipulations in upland loblolly pine (Pinus taeda) forests. For.
Ecol. Man. 256, 2078-2083.
Oxbrough, A., Irwin, S., Kelly, T.C., O'Halloran, J., 2010. Ground-dwelling
invertebrates in reforested conifer plantations. For. Ecol. Man. 259, 21112121.
Pafilis, P., Foufopoulos, J., Poulakakis, N., Lymberakis, P., Valakos, E., 2007.
Digestive performance in five Mediterranean lizard species: effects of
temperature and insularity. J. Comp. Physiol. B-Biochem. Syst. Environ.
Physiol. 177, 49-60.
Palik, B., Engstrom, R.T., 1999. Species Composition. In: Jr, M.L.H. (Ed.),
Maintaining Biodiversity In Forest Ecosystems. Cambridge University
Press, Cambridge, U.K., pp. 65-94.
212
References
Paquet, J.-Y., Vandevyvre, X., Delahaye, L., Rondeux, J., 2006. Bird
assemblages in a mixed woodland–farmland landscape: The
conservation value of silviculture-dependant open areas in plantation
forest. For. Ecol. Man. 227, 59-70.
Paquette, A., Messier, C., 2010. The role of plantations in managing the world's
forests in the Anthropocene. Frontiers in Ecology and the Environment 8,
27-34.
Pardini, R., Faria, D., Accacio, G.M., Laps, R.R., Mariano-Neto, E., Paciencia,
M.L.B., Dixo, M., Baumgarten, J., 2009. The challenge of maintaining
Atlantic forest biodiversity: A multi-taxa conservation assessment of
specialist and generalist species in an agro-forestry mosaic in southern
Bahia. Biol. Cons. 142, 1178-1190.
Parrotta, J.A., Turnbull, J.W., Jones, N., 1997. Catalyzing native forest
regeneration on degraded tropical lands. For. Ecol. Man. 99, 1-7.
Paton, D., O'Connor, J., 2010. The State of Australia’s Birds 2009 - Restoring
Woodland Habitats for Birds. Wingspan 20, S1-S5.
Pawson, S.M., Brockerhoff, E.G., Didham, R.K., 2009. Native forest generalists
dominate carabid assemblages along a stand age chronosequence in an
exotic Pinus radiata plantation. For. Ecol. Man. 258, S108-S116.
Pawson, S.M., Brockerhoff, E.G., Meenken, E.D., Didham, R.K., 2008.
Non-native plantation forests as alternative habitat for native forest
beetles in a heavily modified landscape. Biodivers. Conserv. 17, 11271148.
Pearman, P., 2002. The scale of community structure: habitat variation and
avian guilds in tropical forest understorey. Ecological Mongraphs 72, 1939.
Penn, A.M., Sherman, W.B., Lunney, D., Banks, P.B., 2003. The effects of a
low-intensity fire on small mammals and lizards in a logged, burnt forest.
Wildl. Res. 30, 477-486.
213
References
Pereboom, J.J.M., Beismeijer, J.C., 2003. Thermal constraints for stingless bee
foragers: the importance of body size and colouration. Oecologia 137, 4250.
Perfecto, I., Vandermeer, J., 2010. The agroecological matrix as alternative to
the landsparing/agriculture intensification model. Proc. Natl. Acad. Sci. U.
S. A. 107, 5786-5791.
Peterson, G., Allen, C.R., Holling, C.S., 1998. Ecological resilience, biodiversity,
and scale. Ecosystems 1, 6-18.
Pharo, E.J., Lindenmayer, D.B., 2009. Biological legacies soften pine plantation
effects for bryophytes. Biodivers. Conserv. 18, 1751-1764.
Pike, D.A., Webb, J.K., Shine, R., 2011. Removing forest canopy cover restores
a reptile assemblage. Ecol. Appl. 21, 274-280.
Pineda, E., Halffter, G., 2004. Species diversity and habitat fragmentation: frogs
in a tropical montane landscape in Mexico. Biol. Cons. 117, 499-508.
Pitt, S., 2001. Vertebrate fuana survey of Bago Bluff national park. National
Parks and Wildlife Service, NSW.
Pitt, W.C., 1999. Effects of multiple vertebrate predators on grasshopper habitat
selection: trade-offs due to predation risk, foraging, and thermoregulation.
Evol. Ecol. 13, 499-515.
Planque, B., Loots, C., Petitgas, P., Lindstrom, U., Vaz, S., 2011. Understanding
what controls the spatial distribution of fish populations using a multimodel approach. Fish Oceanogr. 20, 1-17.
Popescu, V.D., Hunter, M.L., 2011. Clear-cutting affects habitat connectivity for
a forest amphibian by decreasing permeability to juvenile movements.
Ecol. Appl. 21, 1283-1295.
Porté, A., Huard, F., Dreyfus, P., 2004. Microclimate beneath pine plantation,
semi-mature pine plantation and mixed broadleaved-pine forest. Agric.
For. Meteorol. 126, 175-182.
Potts, B.M., Barbour, R.C., Hingston, A.B., 2001. Genetic pollution from farm
forestry: using eucalypt species and hybrids. In. RIRDC/L&WA/FWPRDC,
Barton, Australia.
214
References
Poulin, J.F., Villard, M.A., 2011. Edge effect and matrix influence on the nest
survival of an old forest specialist, the Brown Creeper (Certhia
americana). Landsc. Ecol. 26, 911-922.
Pressey, R.L., S., F., Hager, T.C., Woods, C.A., L., T.S., Weinman, K.M., 1996.
How well protected are the forests of north-eastern New South Wales? Analyses of forest environments in relation to formal protection measures,
land tenure, and vulnerability to clearing. For. Ecol. Man. 85, 311-333.
Prevedello, J.A., Vieira, M.V., 2010. Plantation rows as dispersal routes: A test
with didelphid marsupials in the Atlantic Forest, Brazil. Biol. Cons. 143,
131-135.
Price, B., Kutt, A.S., McAlpine, C.A., 2010. The importance of fine-scale
savanna heterogeneity for reptiles and small mammals. Biol. Cons. 143,
2504-2513.
Prieto-Benítez, S., Méndez, M., 2011. Effects of land management on the
abundance and richness of spiders (Araneae): A meta-analysis. Biol.
Cons. 144, 683-691.
Pringle, R.M., Webb, J.K., Shine, R., 2003. Canopy structure, microclimate, and
habitat selection by a nocturnal snake. Ecology 84, 2668-2679.
Pritchard, J.M., Comeau, P.G., 2004. Effects of opening size and stand
characteristics on light transmittance and temperature under young
trembling aspen stands. For. Ecol. Man. 200, 119-128.
Proença, V.M., Pereira, H.M., Guilherme, J., Vicente, L., 2010. Plant and bird
diversity in natural forests and in native and exotic plantations in NW
Portugal. Acta Oecol.-Int. J. Ecol. 36, 219-226.
Prosser, C., Hudson, S., Thompson, M.B., 2006. Effects of urbanization on
behavior, performance, and morphology of the Garden Skink,
Lampropholis guichenoti. J. Herpetol. 40, 151-159.
Pyke, G.H., 1984. Optimal foraging theory : A critical review. Annual Review of
Ecology and Systematics 15, 523-575.
215
References
Rabosky, D.L., Donnellan, S.C., Talaba, A.L., Lovette, I.J., 2007. Exceptional
among-lineage variation in diversification rates during the radiation of
Australia's most diverse vertebrate clade. Proceedings of the Royal
Society B-Biological Sciences 274, 2915-2923.
Radford, J.Q., Bennett, A.F., 2007. The relative importance of landscape
properties for woodland birds in agricultural environments. J. Appl. Ecol.
44, 737-747.
Rambo, T.R., North, M.P., 2008. Spatial and temporal variability of canopy
microclimate in a Sierra Nevada riparian forest. Northwest Sci. 82, 259268.
Rambo, T.R., North, M.P., 2009. Canopy microclimate response to pattern and
density of thinning in a Sierra Nevada forest. For. Ecol. Man. 257, 435442.
Ramírez, P.A., Simonetti, J.A., 2011. Conservation opportunities in commercial
plantations: The case of mammals. J. Nat. Conserv. 19, 351-355.
Ratsirarson, H., Robertson, H.G., Picker, M.D., Noort, S.v., 2002. Indigenous
forests versus exotic eucalypt and pine plantations: a comparison of leaflitter invertebrate communities. African Entomology 10, 93-99.
Read, J.L., Cunningham, R., 2010. Relative impacts of cattle grazing and feral
animals on an Australian arid zone reptile and small mammal
assemblage. Austral Ecol. 35, 314-324.
Reino, L., Porto, M., Morgado, R., Carvalho, F., Mira, A., Beja, P., 2010. Does
afforestation increase bird nest predation risk in surrounding farmland?
For. Ecol. Man. 260, 1359-1366.
Repenning, R.W., Labisky, R.F., 1985. Effects of even-age timber management
on bird communities of the Longleaf Pine forest in Northern Florida. J.
Wildl. Manage. 49, 1089-1098.
Retana, J., Cerdà, X., 2000. Patterns of diversity and composition of
Mediterranean ground ant communities tracking spatial and temporal
variability in the thermal environment. Oecologia 123, 436-444.
216
References
Ricketts, T.H., 2001. The matrix matters: Effective isolation in fragmented
landscapes. The American Naturalist 158, 87-99.
Rodrígues, A.S.L., Andelman, S.J., Bakarr, M.I., Boitani, L., Brooks, T.M.,
Cowling, R.M., Fishpool, L.D.C., Fonseca, G.A.B.d., Gaston, K.J.,
Hoffmann, M., Long, J.S., Marquet, P.A., Pilgrim, J.D., Pressey, R.L.,
Schipper, J., Sechrest, W., Stuart, S.N., Underhill, L.G., Waller, R.W.,
Watts, M.E.J., Yan, X., 2004. Effectiveness of the global protected area
network in representing species diversity. Nature 428, 640-643.
Rodriguez-Serrano, E., Navas, C.A., Bozinovic, F., 2009. The comparative field
body temperature among Liolaemus lizards: Testing the static and the
labile hypotheses. J. Therm. Biol. 34, 306-309.
Rosenberg, M., Adams, D.C., J., G., 1997. MetaWin. Sinauer Associates,
Sunderland, Massachusetts.
Row, J.R., Blouin-Demers, G., 2006. Thermal quality influences effectiveness of
thermoregulation, habitat use, and behaviour in milk snakes. Oecologia
148, 1-11.
Ryan, T.J., Philippi, T., Leiden, Y.A., Dorcas, M.E., Wigley, T.B., Gibbons, J.W.,
2002. Monitoring herpetofauna in a managed forest landscape: effects of
habitat types and census techniques. For. Ecol. Man. 167, 83-90.
Sabo, J.L., 2003. Hot rocks or no hot rocks: overnight retreat availability and
selection by a diurnal lizard. Oecologia 136, 329-335.
Sala, O.E., Chapin III, F.S., Armesto, J.J., Berlow, E., Bloomfiled, J., Dirzo, R.,
Huber-Sanwald, E., Huenneke, L.F., Jackson, R.B., Kinzig, A., Leemans,
R., Lodge, D.M., Mooney, H.A., Oesterheld, M., Poff, N.L., Sykes, M.T.,
Walker, B.H., Walker, M., Wall, D.H., 2000. Global biodiversity scenarios
for the year 2100. Science 287, 1770-1774.
Sample, V.A., 2003. Forest plantations as components in a global biodiversity
conservation strategy: the role of developed, temperate-forest countries.
World Forestry Congress XII, Canada.
217
References
Samways, M.J., Caldwell, P.M., Osborn, R., 1996. Ground-living invertebrate
assemblages in native, planted and invasive vegetation in South Africa.
Agriculture, Ecosystems and Environment 59, 19-32.
Sartorius, S.S., do Amaral, J.P.S., Durtsche, R.D., Deen, C.M., Lutterschmidt,
W.I., 2002. Thermoregulatory accuracy, precision, and effectiveness in
two sand-dwelling lizards under mild environmental conditions. Can. J.
Zool.-Rev. Can. Zool. 80, 1966-1976.
Saunders, S.C., Chen, J.Q., Crow, T.R., Brosofske, K.D., 1998. Hierarchical
relationships between landscape structure and temperature in a managed
forest landscape. Landsc. Ecol. 13, 381-395.
Sax, D.F., 2002. Equal diversity in disparate species assemblages: a
comparison of native and exotic woodlands in California. Glob. Ecol.
Biogeogr. 11, 49-57.
Schnell, M.R., Pik, A.J., Dangerfield, J.M., 2003. Ant community succession
within eucalypt plantations on used pasture and implications for
taxonomic sufficiency in biomonitoring. Austral Ecol. 28, 553-565.
Schultz, T.D., 1998. The utilization of patchy thermal microhabitats by the
ectothermic insect predator, Cicindela sexguttata. Ecological Entomology
23, 444-450.
Schulze, C.H., Waltert, M., Kessler, P.J.A., Pitopang, R., Shahabuddin,
Veddeler, D., Mühlenberg, M., Gradstein, S.R., Leuschner, C., SteffanDewenter, I., Tscharntke, T., 2004. Biodiversity indicator groups of
tropical land-use systems: comparing plants, birds, and insects. Ecol.
Appl. 14, 1321-1333.
Scott, D.M., Brown, D., Mahood, S., Denton, B., Anastasia Silburn,
Rakotondraparany, F., 2006. The impacts of forest clearance on lizard,
small mammal and bird communities in the arid spiny forest, southern
Madagascar. Biol. Cons. 127, 72-87.
Sedgeley, J.A., 2001. Quality of cavity microclimate as a factor influencing
selection of maternity roosts by a tree-dwelling bat, Chalinolobus
tuberculatus, in New Zealand. J. Appl. Ecol. 38, 425-438.
218
References
Sedjo, R.A., Botkin, D., 1997. Using forest plantations to spare natural forests.
Environment 39, 14-22.
Seebacher, F., Alford, R.A., 2002. Shelter microhabitats determine body
temperature and dehydration rates of a terrestrial amphibian (Bufo
marinus). J. Herpetol. 36, 69-75.
Sheridan, J.A., Bickford, D., 2011. Shrinking body size as an ecological
response to climate change. Nature Clim. Change 1, 401-406.
Sinervo, B., Adolph, S.C., 1994. Growth plasticity and thermal opportunity in
Sceloporus lizards. Ecology 75, 776-790.
Singleton, G.R., 1995. House mouse. In: Strahan, R. (Ed.), The Mammals of
Australia. Reed books, Chatswood , NSW, pp. 646-647.
Skelly, D.K., Werner, E.E., S.A.Cortwright, 1999. Long-term dynamics of a
Michigan amphibian assemblage. Ecology 80, 2326-2337.
Skinner, ee, M.S.Y., Hutchinson, M.N., 2008. Rapid and repeated limb loss in
a clade of scincid lizards. BMC Evol. Biol. 8, 310.
Spellerberg, I., 1972a. Temperature tolerances of southeast Australian reptiles
examined in relation to reptile thermoregulatory behaviour and distribution.
Oecologia 9, 23-46.
Spellerberg, I., Sawyer, J., 1997. Biological diversity in plantation forests. In:
Hale, P., Lamb, D. (Eds.), Conservation Outside Nature Reserves. Centre
for Conservation Biology, University of Queensland, Brisbane: Australia,
pp. 517-522.
SPSS, 2012. IBM SPSS Statistics Version 21. In. IBM Corporation.
Stephens, S.S., Wagner, M.R., 2007. Forest Plantations and Biodiversity: A
Fresh Perspective. Journal of Forestry 107, 307-313.
Stevens, V., 1997. The ecological role of coarse woody debris: an overview of
the ecological importance of CWD in B.C. forests. British Columbia
Ministry of Forests Research Program, Working Paper 30. Victoria, British
Columbia.
Stoutjesdijk, P., Barkman, J.J., 1992. Microclimate, Vegetation and Fauna.
Opulus Press, Grangýrde, Sweden.
219
References
Strahan, R., 1995. The Mammals of Australia. Reed Books, Sydney, Australia.
Strauss, S.Y., 2001. Benefits and risks of biotic exchange between Eucalyptus
plantations and native Australian forests. Austral Ecol. 26, 44–45.
Strobl, S., Fetene, M., Beck, E.H., 2011. Analysis of the "shelter tree-effect" of
natural and exotic forest canopies on the growth of young Podocarpus
falcatus trees in southern Ethiopia. Trees - Structure and Function 25,
769-783.
Sullivan, T.P., Sullivan, D.S., Lindgren, P.M.F., Ransome, D.B., 2009. Stand
structure and the abundance and diversity of plants and small mammals
in natural and intensively managed forests. For. Ecol. Man. 258, S127S141.
Szarzynski, J., Anhuf, D., 2001. Micrometeorological conditions and canopy
energy exchanges of a neotropical rain forest (Surumoni-Crane Project,
Venezuela). Plant Ecology 153, 231-239.
Taniguchi, H., Nakano, S., Tokeshi, M., 2003. Influences of habitat complexity
on the diversity and abundance of epiphytic invertebrates on plants.
Freshw. Biol. 48, 718-728.
Tews, J., Brose, U., Grimm, V., Tielbörger, K., Wichmann, M.C., Schwager, M.,
Jeltsch, F., 2004. Animal species diversity driven by habitat
heterogeneity/diversity: the importance of keystone structures. J.
Biogeogr. 31, 79-92.
Todd, B.D., Andrews, K.M., 2008. Response of a reptile guild to forest
harvesting. Conserv. Biol. 22, 753-761.
Tomasevic, J.A., Estades, C.F., 2008. Effects of the structure of pine plantations
on their "softness" as barriers for ground-dwelling forest birds in southcentral Chile. For. Ecol. Man. 255, 810-816.
Tracy, C.R., Christian, K.A., 1986. Ecological relations among space, time and
thermal niche axes Ecology 67, 609-615.
Troost, T.A., Kooi, B.W., Dieckmann, U., 2008. Joint evolution of predator body
size and prey-size preference. Evol. Ecol. 22, 771-799.
220
References
Tscharntke, T., Tylianakis, J.M., Rand, T.A., Didham, R.K., Fahrig, L., Batáry, P.,
Bengtsson, J., Clough, Y., Crist, T.O., Dormann, C.F., Ewers, R.M.,
Fründ, J., Holt, R.D., Holzschuh, A., Klein, A.M., Kleijn, D., Kremen, C.,
Landis, D.A., Laurance, W., Lindenmayer, D., Scherber, C., Sodhi, N.,
Steffan-Dewenter, I., Thies, C., van der Putten, W.H., Westphal, C., 2012.
Landscape moderation of biodiversity patterns and processes - eight
hypotheses. Biol. Rev. 87, 661-685.
Turnbull, J.W., 1999. Eucalypt plantations. New For. 17, 37-52.
Umetsu, F., Pardini, R., 2007. Small mammals in a mosaic of forest remnants
and anthropogenic habitats-evaluating matrix quality in an Atlantic forest l
landscape. Landsc. Ecol. 22, 517-530.
Urbina-Cardona, J.N., Olivares-Pérez, M., Reynoso, V.H., 2006. Herpetofauna
diversity and microenvironment correlates across a pasture–edge–interior
ecotone in tropical rainforest fragments in the Los Tuxtlas Biosphere
Reserve of Veracruz, Mexico. Biol. Cons. 132, 61-75.
Valentine, L.E., Roberts, B., Schwarzkopf, L., 2007. Mechanisms driving
avoidance of non-native plants by lizards. J. Appl. Ecol. 44, 228-237.
Vallan, D., 2002. Effects of anthropogenic environmental changes on amphibian
diversity in the rain forests of eastern Madagascar. J. Trop. Ecol. 18, 725742.
Van Calster, H., Baeten, L., Verheyen, K., De Keersmaeker, L., Dekeyser, S.,
Rogister, J.E., Hermy, M., 2008. Diverging effects of overstorey
conversion scenarios on the understorey vegetation in a former coppicewith-standards forest. For. Ecol. Man. 256, 519-528.
Van Damme, R., Bauwens, D., Verheyen, R.F., 1990. Evolutionary rigidity of
thermal physiology : the case of the cool temperate lizard Lacerta vivipara.
Oikos 57, 61-67.
Van Damme, R., Bauwens, D., Verheyen, R.F., 1991. The thermal dependence
of feeding behaviour, food consumption and gut-passage time in the
lizard Lacerta vivipara Jacquin. Funct. Ecol. 5, 507-517.
221
References
Van Zandt, P.A., Mopper, S., 1998. A meta-analysis of adaptive deme formation
in phytophagous insect populations. Am. Nat. 152, 595-604.
Vasconcelos, H.L., Vilhena, J.M.S., Magnusson, W.E., Albernaz, A., 2006.
Long-term effects of forest fragmentation on Amazonian ant communities.
J. Biogeogr. 33, 1348-1356.
Vellend, M., Verheyen, K., Jacquemyn, H., Kolb, A., van Calster, H., Peterken,
G. Hermy, M., 2006. Extinction debt of forest plants persists for more than
a century following habitat fragmentation. Ecology 87, 542-548.
Verbeke, G., Molenberghs, G., 2000. Linear Mixed Models for Longitudinal Data.
Springer, New York.
Vernes, K., Dunn, L., 2009. Mammal mycophagy and fungal spore dispersal
across a steep environmental gradient in eastern Australia. Austral Ecol.
34, 69-76.
Vickers, M., Manicom, C., Schwarzkopf, L., 2011. Extending the Cost-Benefit
Model of Thermoregulation: High-Temperature Environments. Am. Nat.
177, 452-461.
Vitt, L.J., Sartorius, S.S., Avila-Pires, T.C.S., Zani, P.A., Esposito, M.C., 2005.
Small in a big world: Ecology of leaf-litter geckos in new world tropical
forests. Herpetol. Monogr. 19, 137-152.
Volpato, G.H., Prado, V.M., dos Anjos, L., 2010. What can tree plantations do
for forest birds in fragmented forest landscapes? A case study in southern
Brazil. For. Ecol. Man. 260, 1156-1163.
Walsberg, G.E., Tracy, R.L., Hoffman, T.C.M., 1997. Do metabolic responses to
solar radiation scale directly with intensity of irradiance? J. Exp. Biol. 200,
2115-2121.
Walsberg, G.E., Weathers, W.W., 1986. A simple technique for estimating
operative environmental temperature. J. Therm. Biol. 11, 67-72.
Wampold, B.E., Mondin, G.W., Moody, M., Stich, F., Benson, K., Ahn, H.-n.,
1997. A meta-analysis of outcome studies comparing bona fide
psychotherapies: Empirically, "All Must Have Prizes". Psychological
Bulletin 122, 203-215.
222
References
Wanger, T.C., Saro, A., Iskandar, D.T., Brook, B.W., Sodhi, N.S., Clough, Y.,
Tscharntke, T., 2009. Conservation value of cacao agroforestry for
amphibians and reptiles in South-East Asia: combining correlative models
with follow-up field experiments. J. Appl. Ecol. 46, 823-832.
Wapstra, E., Swain, R., 1996. Feeding ecology of the Tasmanian spotted skink,
Niveoscincus ocellatus (Squamata: Scincidae). Australian Journal of
Zoology 44, 205-213.
Ward, A.J.W., Hensor, E.M.A., Webster, M.M., Hart, P.J.B., 2010. Behavioural
thermoregulation in two freshwater fish species. J. Fish Biol. 76, 22872298.
Waters, J.R., McKelvey, C.J., Zabel, C.J., Oliver, W.W., 1994. The effects of
thinning and broadcast burning on sporocarp production of hypogeous
fungi. Canadian Journal of Forest Research 24, 1516-1522.
Watts, C.H.S., Braithwaite, R.W., 1978. The diet of Rattus lutreolus and five
other rodents in Southern Victoria. Aust. Wild. Res. 5, 47-57.
Webb, J.K., Shine, R., 1998. Using thermal ecology to predict retreat-site
selection by an endangered snake species. Biol. Cons. 86, 233-242.
Wehrly, K.E., Wiley, M.J., Seelbach, P.W., 2003. Classifying regional variation in
thermal regime based on stream fish community patterns. Transactions of
the American Fisheries Society 132, 18-38.
Williams, N.M., Crone, E.E., Roulston, T.H., Minckley, R.L., Packer, L., Potts,
S.G., 2010. Ecological and life-history traits predict bee species
responses to environmental disturbances. Biol. Cons. 143, 2280-2291.
Williams, S.H., Peiffer, E., Ford, S., 2009. Gape and bite force in the rodents
Onychomys leucogaster and Peromyscus maniculatus: Does jaw-muscle
anatomy predict performance? J. Morphol. 270, 1338-1347.
Wilson, S.K., and D. G. Knowles, 1988. Australia’s reptiles: a photographic
reference to the terrestrial reptiles of Australia. Collins, Sydney, Australia.
223
References
Woinarski, J.C.Z., Ash, A.J., 2002. Responses of vertebrates to pastoralism,
military land use and landscape position in an Australian tropical savanna.
Austral Ecol. 27, 311-323.
Wolf, B.O., Walsberg, G.E., 1996. Thermal effects of radiation and wind on a
small bird and implications for microsite selection. Ecology 77, 2228-2236.
Wright, T.E., Kasel, S., Tausz, M., Bennett, L.T., 2010. Edge microclimate of
temperate woodlands as affected by adjoining land use. Agric. For.
Meteorol. 150, 1138-1146.
Yang, Z.L., Dai, Y., Dickinson, R.E., Shuttleworth, W.J., 1999. Sensitivity of
ground heat flux to vegetation cover fraction and leaf area index. J.
Geophys. Res.-Atmos. 104, 19505-19514.
Yates, C.J., Norton, D.A., Hobbs, R.J., 2000. Grazing effects on plant cover, soil
and microclimate in fragmented woodlands in south-western Australia:
implications for restoration. Austral Ecol. 25, 36-47.
Yirdaw, E., Luukkanen, O., 2004. Photosynthetically active radiation
transmittance of forest plantation canopies in the Ethopian highlands. For.
Ecol. Man. 188, 17-24.
Yu, X.D., Luo, T.H., Zhou, H.Z., 2006. Distribution of carabid beetles among
regenerating and natural forest types in Southwestern China. For. Ecol.
Man. 231, 169-177.
Yu, X.D., Luo, T.H., Zhou, H.Z., 2008. Distribution of carabid beetles among
40-year-old regenerating plantations and 100-year-old naturally
regenerated forests in Southwestern China. For. Ecol. Man. 255, 26172625.
Yuan, H.W., Ding, T.S., Hsieh, H.I., 2005. Short-term responses of animal
communities to thinning in a Cryptomeria japonica (Taxodiaceae)
plantation in Taiwan. Zool. Stud. 44, 393-402.
Yuan, S.F., Ren, H., Liu, N., Wang, J., Guo, Q.F., 2013. Can thinning of
overstorey trees and planting of native tree saplings increase the
establishment of native trees in exotic Acacia plantations in south China?
Journal of Tropical Forest Science 25, 79-95.
224
References
Zborowski, P., Storey, R., 2003. A field guide to insects in Australia. Reed New
Holland, Sydney.
Zhao, J., Wang, X.L., Shao, Y.H., Xu, G.L., Fu, S.L., 2011. Effects of vegetation
removal on soil properties and decomposer organisms. Soil Biol.
Biochem. 43, 954-960.
Zhao, S., Fang, J., Peng, C., Tang, Z., 2006. Relationships between species
richness of vascular plants and terrestrial vertebrates in China: analyses
based on data of nature reserves. Diversity and Distributions 12, 189-194.
Zurita, G.A., Bellocq, M.I., 2010. Spatial patterns of bird community similarity:
bird responses to landscape composition and configuration in the Atlantic
forest. Landsc. Ecol. 25, 147-158.
Zurita, G.A., Rey, N., Varela, D.M., Villagra, M., Bellocq, M.I., 2006. Conversion
of the Atlantic Forest into native and exotic tree plantations: Effects on
bird communities from the local and regional perspectives. For. Ecol. Man.
235, 164-173.
225
Appendices
Appendix 1
Table 1. Summary statistics for all bird species recorded from young and old plantations, logged
and old growth native forests from twenty field sites on the Mid-North Coast of NSW between
2001 and 2002. Guild membership is specified by strata commonly used and diet. Notations are
A= all strata, C=canopy, Gr= ground, G-L= ground-low, M-C= midstorey-canopy, G= granivore
C= carnivore, H=herbivore, N= nectarivore, O= omnivore, I= insectivore, F= frugivore. Habitat
associations are F = forest, W = woodland, G = generalist. Species indicated by * are excluded
from analyses as they were only documented overflying field sites.
Family
Acanthizidae
Acanthizidae
Acanthizidae
Acanthizidae
Acanthizidae
Acanthizidae
Accipitridae
Alcedinidae
Apodidae
Cacatuidae
Cacatuidae
Campephagidae
Campephagidae
Caprimulgidae
Climacteridae
Climacteridae
Columbidae
Columbidae
Columbidae
Columbidae
Corvidae
Cracticidae
Cracticidae
Cracticidae
Cuculidae
Cuculidae
Cuculidae
Estrildidae
Halcyonidae
Maluridae
Maluridae
Maluridae
Megapodidae
Meliphagidae
Meliphagidae
Meliphagidae
Meliphagidae
Meliphagidae
Meliphagidae
Meliphagidae
Meliphagidae
Menuridae
Monarchidae
Monarchidae
Monarchidae
Nectariniidae
Oriolidae
Orthonychidae
Pachycephalidae
Pachycephalidae
Pachycephalidae
pachycephalidae
Paradisaeidae
Pardalotidae
Petroicidae
Petroicidae
Petroicidae
Petroicidae
Psittacidae
Psittacidae
Psittacidae
Psittacidae
Psophodidae
Ptilonorhychidae
Ptilonorhychidae
Rhipiduridae
Rhipiduridae
Strigidae
Strigiformes
Zosteropidae
Species
Brown gerygone
Brown thornbill
Striated thornbill
White-browed scrubwren
Yellow thornbill
Yellow-throated scrubwren
Brown goshawk
Azure kingfisher
White-throated needletail*
Glossy black cockatoo
Yellow-tailed black cockatoo
Black-faced cuckoo shrike
White-bellied cuckoo-shrike
White-throated nightjar
Brown treecreeper
White-throated treecreeper
Brown pigeon
Peaceful dove
Wompoo pigeon
Wonga pigeon
Australian Raven*
Australian magpie
Pied butcherbird
Pied currawong
Channel-billed cuckoo
Horsfield's bronze cuckoo
Pheasant coucal
Red-browed finch
Laughing kookaburra
Red-backed wren
Superb wren
Variagated wren
Australian brush turkey
Bell miner
Eastern spinebill
Lewins honeyeater
Little friar bird
New holland honeyeater
White-eared honeyeater
White-naped honeyeater
Yellow-faced honeyeater
Superb lyrebird
Black-faced monarch
Restless flycatcher
Satin flycatcher
Mistletoebird
Olive-backed oriole
Logrunner
Crested Bell bird
Golden whistler
Grey shrike thrush
Rufous whistler
Paradise riflebird
Spotted pardalote
Jacky winter
Eastern yellow robin
Rose robin
Scarlet robin
Crimson rosella
King parrot
Rainbow lorikeet
Scaly-breasted lorikeet
Eastern whipbird
Green catbird
Satin bowerbird
Grey fantail
Rufous fantail
Southern boobook owl
Sooty owl
Silvereye
Old Growth Native
captures mean se
13
2.6 0.32
43
8.6 0.83
7
1.4 0.37
25
5
0.30
7
1.4 0.14
2
0.4 0.07
1
0.2 0.05
3
0.6 0.11
1
0.2 0.05
1
0.2 0.05
1
0.2 0.05
12
2.4 0.40
150
30 1.34
2
0.4 0.11
9
1.8 0.13
10
2
0.40
4
0.8 0.10
9
1.8 0.48
5
1
0.27
3
0.6 0.07
4
0.8 0.21
75
15 0.89
7
1.4 0.37
5
1
0.27
18
3.6 0.55
13
2.6 0.35
29
5.8 0.41
0
0
0.00
6
1.2 0.20
6
1.2 0.26
4
0.8 0.15
93
18.6 0.80
25
5
0.47
36
7.2 1.22
2
0.4 0.07
2
0.4 0.11
26
5.2 0.18
26
5.2 0.85
13
2.6 0.42
6
1.2 0.21
35
7
1.23
0
0
0.00
60
12 1.06
14
2.8 0.32
8
1.6 0.20
90
18 2.45
71
14.2 1.11
5
1
0.08
2
0.4 0.11
0
0
0.00
Logged Native
captures mean se
12
2.4 0.23
1
0.2 0.05
6
1.2 0.20
4
0.8 0.21
7
1.4 0.26
3
0.6 0.16
5
1
0.12
5
1
0.21
36
7.2 0.71
132
26.4 1.76
2
0.4 0.11
3
0.6 0.11
3
0.6 0.11
16
3.2 0.23
3
0.6 0.16
3
0.6 0.11
1
0.2 0.05
7
1.4 0.31
59
11.8 1.35
5
1
0.15
1
0.2 0.05
61
12.2 1.12
48
9.6 1.17
11
2.2 0.58
2
0.4 0.11
1
0.2 0.05
30
6
0.24
10
2
0.28
21
4.2 0.48
1
0.2 0.05
1
0.2 0.05
0
0
0.00
1
0.2 0.05
1
0.2 0.05
3
0.6 0.16
56
11.2 0.57
23
4.6 0.38
1
0.2 0.05
46
9.2 0.57
1
0.2 0.05
10
2
0.47
4
0.8 0.13
111
22.2 2.95
2
0.4 0.07
13
2.6 0.20
1
0.2 0.05
7
1.4 0.16
22
4.4 0.26
36
7.2 0.65
1
0.2 0.05
-
Old Plantation
captures mean se
1
0.2 0.05
2
0.4 0.11
58
11.6 1.38
9
1.8 0.32
3
0.6 0.16
11
2.2 0.20
17
3.4 0.31
23
4.6 0.35
2
0.4 0.11
1
0.2 0.05
13
2.6 0.29
18
3.6 0.39
7
1.4 0.23
31
6.2 0.73
22
4.4 0.61
25
5
0.25
30
6
0.42
37
7.4 0.72
0
0
0.00
22
4.4 0.61
1
0.2 0.05
10
2
0.40
2
0.4 0.07
2
0.4 0.07
7
1.4 0.37
8
1.6 0.36
11
2.2 0.18
30
6
0.42
7
1.4 0.31
33
6.6 0.37
4
0.8 0.21
2
0.4 0.11
21
4.2 0.69
17
3.4 0.34
2
0.4 0.11
32
6.4 0.49
4
0.8 0.15
2
0.4 0.07
-
Young plantation
captures mean se
6
1.2 0.21
30
6
1.15
1
0.2 0.05
5
1
0.27
2
0.4 0.11
8
1.6 0.22
2
0.4 0.11
1
0.2 0.05
79
15.8 0.58
3
0.6 0.07
6
1.2 0.21
14
2.8 0.41
4
0.8 0.15
6
1.2 0.21
6
1.2 0.15
26
5.2 1.19
8
1.6 0.20
16
3.2 0.62
75
15 1.18
6
1.2 0.26
2
0.4 0.07
57
11.4 0.73
9
1.8 0.24
2
0.4 0.11
4
0.8 0.15
7
1.4 0.25
10
2
0.17
3
0.6 0.11
24
4.8 0.65
8
1.6 0.14
53
10.6 0.38
15
3
0.57
9
1.8 0.41
3
0.6 0.11
36
7.2 0.41
1
0.2 0.05
64
12.8 0.90
Habitat
Guild
F
F
F
F
W
F
F
G
W
W
F
W
W
W
W
F
F
W
F
F
W
W
W
W
W
W
W
G
W
G
G
W
F
W
F
F
F
W
F
F
W
F
F
W
F
W
F
W
W
F
F
W
F
W
W
F
F
W
F
F
G
F
F
F
F
F
F
G
F
G
Ar, N/I
Ar, N/I
C, N/I
G-L, I
C, F/O
G-L, I
A, C/I
G-L, C
C, N/I
C, G
C, G
C, F/O
C, N/I
G-L, I
Ar, N/I
Ar, N/I
M-C, N/I/F
G-L, G
C, F/O
G-L, G
G-L, O
G-L, O
G-L, O
A, O
C, F/O
Ar, N/I
Gr, I
G-L, G
G-L, C
G-L, I
G-L, I
G-L, I
G-L, O
M-C, N/I/F
Ar, N/I
M-C, N/I/F
C, N/I
Ar, N/I
M-C, N/I/F
Ar, N/I
C, F/O
Gr, I
C, N/I
Ar, N/I
C, N/I
C, F/O
C, N/I
Gr, I
C, N/I
Ar, N/I
A, C/I
C, N/I
C, N/I
C, N/I
G-L, I
G-L, I
Ar, N/I
G-L, I
C, G
C, G
C, N/I
C, N/I
Gr, I
M-C, N/I/F
A, O
Ar, N/I
G-L, I
A, C/I
A, C/I
M-C, N/I/F
226
Appendices
Table 2. Summary statistics for mammal, frog and reptile species recorded from young and old
plantations, logged and old growth native forests from twenty field sites on the Mid-North Coast
of NSW between 2001 and 2002, and analyzed in chapter 3. Guild membership is specified by
strata commonly used and diet. Notations are A= all strata, C=canopy, Gr= ground, G-L=
ground-low, M-C= midstorey-canopy, G= granivore C= carnivore, H=herbivore, N= nectarivore,
O= omnivore, I= insectivore, F= frugivore. Habitat associations are F = forest, W = woodland, G
= generalist. Species indicated by * are excluded from analyses. Values represent total numbers
of unique captures.
Taxon
Mammals
Species
Antechinus stuartii
Antechinus swainsonii
Isoodon macrourus
Melomys cervinipes
Mus musculus
Planigale maculata
Pseudocheirus peregrinus*
Pteropus scapulatus*
Rattus fuscipes
Rattus lutreolus
Sminthopsis murina
Trichosurus vulpecula*
Old Growth Native
captures mean se
37
7.4 0.95
1
0.2 0.13
1
0.2 0.13
8
1.6 0.39
7
1.4 0.48
10
2 0.82
76
15.2 1.53
-
Logged Native
captures mean se
15
3 0.46
4
0.8 0.52
4
0.8 0.38
6
1.2 0.38
12
2.4 0.72
59
11.8 1.34
2
0.4 0.16
Old Plantation
captures mean se
20
4 0.84
0
0 0.00
6
1.2 0.32
9
1.8 0.59
32
6.4 1.54
22
4.4 0.97
7
1.4 0.44
4
0.8 0.32
Young plantation
Habitat
Guild
captures mean se AssociationSpecification
9
1.8 0.56
F
Gr, I
0
0 0.00
F
Gr, I
4
0.8 0.24
W
Gr, O
F
Gr, H
7
1.4 0.33
G
Gr, O
3
0.6 0.16
G
Gr, I
F
A, H/N
G
A, H/N
1
0.2 0.13
F
Gr, O
15
3 0.68
W
Gr, H
5
0.6 0.16
W
Gr, I
W
A, H/N
Amphibians
Crinia signifera
Limnodynastes peronii
Mixophyes fasciolatus
Pseudophryne coriacea
Uperolia fusca
2
28
3
0.4
5.6
0.6
0.24
4.13
0.24
1
5
53
4
0.2
1
10.6
0.8
0.20
0.55
2.69
0.37
2
5
41
8
0.4
1
8.2
1.6
0.24
0.45
5.58
0.93
3
2
0.6
0.4
0.60
0.24
G
G
F
W
F
Gr, I
Gr, I
Gr, I
Gr, I
Gr, I
Adrasteia amicula
Amphibolurus muricatus
Cacophis kreffti
Calyptotis ruficaudata
Cryptophis nigrescens
Ctenotus robustus
Cyclodomorphus gerrardi
Demanisa psammophis
Drysdalia coronoides
Egernia mcpheei
Eulamprus murrayi
Eulamprus quyoii
Eulamprus tenuis
Hoplocephalus stephensi
Hypsilurus spinipes
Lampropholis delicata
Lampropholis guichenoti
Lerista muelleri
Lialis burtonis
Morelia spilota
Physignathus lesueurii
Pseudechis porphyriacus
Ramphotyphlops nigrescens
Rhinoplocephalus nigrostriatus
Saltuarius swainii
Tiliqua scincoides
Vermicella annulata
1
8
3
4
46
1
1
2
6
16
7
7
4
3
0
8
3
0.2
1.6
0.6
0.8
9.2
0.2
0.2
0.4
1.2
3.2
1.4
1.4
0.8
0.6
0.09
0.30
0.11
0.32
1.11
0.09
0.09
0.11
0.21
0.35
0.26
0.30
0.26
0.18
12
3
3
21
12
2
1
7
2.4
0.6
0.6
4.2
2.4
0.4
0.2
1.4
0.22
0.18
0.18
0.54
0.41
0.11
0.09
0.11
2
15
1
1
26
40
1
2
2
-
0.4
3
0.2
0.2
5.2
8
0.2
0.4
0.4
-
0.11
0.20
0.09
0.09
0.38
0.83
0.09
0.11
0.11
-
3.4
0.6
0.2
0.2
0.8
0.2
0.8
3
0.4
1
-
0.55
0.11
0.09
0.09
0.09
0.09
0.16
0.44
0.11
0.24
-
1.6
0.6
0.18
0.11
1
-
0.2
-
0.09
-
1
-
0.2
-
0.09
-
17
3
1
1
4
1
4
15
2
5
2
2
-
0.4
-
0.11
-
W
W
F
F
G
W
F
G
G
F
F
F
F
F
F
G
G
W
G
F
F
G
W
W
F
G
G
Gr, I
G-L, I
Gr, C
Gr, I
Gr, I
Gr, I
G-L, I
Gr, C
Gr, C
Gr, O
Gr, I
Gr, I
G-L, I
A, C-I
A, C-I
Gr, I
Gr, I
Gr, I
Gr, C
A, C-I
Gr, O
Gr, C
Gr, I
Gr, I
A, C-I
Gr, O
Gr, C
Reptiles
227
Appendices
Appendix 2
Summary statistics for all herpetofaunal and mammal species recorded from young and old
plantations, logged and old growth native forests from twenty field sites on the Mid-North Coast
of NSW between 2002 and 2003 (as described in chapter 4). Species indicated by * were
excluded from analyses. Values represent total numbers of unique captures.
Mammals
Reptiles
Amphibians
Species
Antechinus stuartii
Antechinus swainsonii
Isoodon macrourus*
Melomys cervinipes*
Mus musculus
Planigale maculata
Rattus fuscipes
Rattus lutreolus
Sminthopsis murina
Adrasteia amicula
Amphibolurus muricatus
Cacophis kreffti*
Calyptotis ruficaudata
Concinnia tenuis*
Ctenotus robustus
Drysdalia coroniodes*
Egernia mcpheei*
Eulamprus quyoii*
Eulamprus murrayi*
Hemisphaerodon gerrardi*
Hypsilurus spinipes*
Lampropholis delicata
Lampropholis guichenoti
Lerista mulleri
Lialis burtonis*
Pseudechis porphyriacus*
Ramphotyphlops nigrescens*
Rhinoplocephalus nigrescens*
Saltuarius swainii*
Tiliqua scincoides
Crinia signifera
Limnodynastes peroni
Mixophys fasciolatus*
Pseudophryne coriacea
Uperolia fusca
N1
10
2
28
3
1
23
6
5
5
3
1
3
9
1
Old growth
N2 N3 N4
12 11 12
- 2 1 - 6 - 6
- - - - 32 28 35
- - - - - - - - 2 1 3
3 5 2
- 1 1
- - - - - - 2
- - 1
12 10 10
- - 2 3 5
15 9 8
- - 5 6 1
- - - - 1 - - - 1 2 2
- - - - - - 1 1 10 10 - - -
N5
9
2
56
1
1
1
11
2
4
7
1
1
8
1
-
LN1
1
27
2
11
3
15
-
Logged native
LN2 LN3 LN4
8
6
5
4
1
2
1
3
2
26 35 30
5
4
3
2
4
1
2
13 17 5
3
1
2
3
1
3
3
5
24 16 17
2
3
LN5
20
3
38
3
1
7
17
2
OP1
21
3
9
6
4
3
1
19
2
6
3
15
-
Old plantation
OP2 OP3 OP4
16 25 19
3
1
1
1
4
1
- 21 25
8 12 8
4
7
3
5
3
5
3
2
4
7
5
3
1
1
18 29 11
14 37 6
1
1
1
4
4
5
5
26 61 12
6
3
-
OP5
21
1
1
23
2
1
12
8
2
Young plantation
YP1 YP2 YP3 YP4 YP5
3
3 4
2
2
18 6 17 11 15
1
3
7 7
12 5 2 7 9
4 4 3
11 5 8 2 20
5
3
- 11 7 2 3 3
1
8 21 14 5 31
11 44 14 6 43
1 2
1 1 2
2
1 1 2 2
1
2
2 2 3
2
9 3
2
8
2 1
1
228
Appendices
Appendix 3
Summary statistics for all herpetofaunal and mammal species recorded from young plantations
and adjacent native forests ten field sites on the Mid-North Coast of NSW between 2002 and
2004 (as described in chapter 5). Values represent total numbers of unique captures.
Taxon
Mammals
Reptiles
Amphibians
Species richness
Species
Antechinus stuartii
Isoodon macroura
Mus musculus
Planigale maculata
Rattus fuscipes
Rattus lutreolus
Sminthopsis murina
Adrasteia amicula
Amphibolurus muricatus
Cacophis kreffti
Calyptotis ruficaudata
Ctenotus robustus
Cyclodomorphus gerrardi
Demansia psammophis
Lampropholis delicata
Lampropholis guichenoti
Lerista mulleri
Lialis burtonis
Pseudechis porphyriacus
Ramphotyphlops nigrescens
Rhinoplocephalus nigrescens
Tiliqua scincoides
Crinia signifera
Limnodynastes peroni
Pseudophryne coriacea
Uperolia fusca
M1
11
2
12
16
4
1
13
-
M2
1
1
2
2
1
-
Matrix
M3
1
4
1
12
2
1
14
30
9
1
4
2
3
1
n=20
M4
6
1
16
1
1
3
15
1
1
1
1
1
5
-
M5
6
25
4
3
1
2
14
12
0
2
1
0
2
1
-
YP1
12
-
Young Plantation
YP2 YP3 YP4
2
10
10
6
1
1
5
2
3
2
3
8
2
6
1
1
1
3
6
1
24
4
1
1
1
2
2
1
1
v
1
1
n=19
Habit
YP5
1
3
17
3
1
1
15
22
1
2
1
1
-
F
W
G
G
F
W
W
W
W
F
F
W
F
G
G
G
W
G
G
W
W
G
G
W
W
F
229