Landscape Ecology 16: 743–755, 2001.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.
743
Land ownership and other landscape-level effects on biodiversity in
southern Ontario’s Niagara Escarpment Biosphere Reserve, Canada
Jon Lovett-Doust∗ & Kathryn Kuntz
Department of Biology, University of Windsor, Windsor, Ontario N9B 3P4, Canada (∗ author for correspondence,
e-mail: [email protected]
Received 18 May 2000; Revised 21 August 2001; Accepted 21 August 2001
Key words: biodiversity, conservation, land management, landscape ecology, Niagara Escarpment ownership
Abstract
We investigated effects of landscape-level factors on measures of biodiversity using published descriptions for 98
significant natural areas along the Niagara Escarpment. This is a 725 km, largely forested, Paleozoic limestone
escarpment that, excepting the Great Lakes, is the most prominent topographical feature of southern Ontario,
Canada. Results show highly significant differences in mean site size and extent of forest interior among natural
areas of different ownership classes, with larger and more forested sites being under mixed (private + public)
ownership, but no significant difference between sites of public and private ownership. Analysis of covariance
demonstrated that after controlling for differences in landscape-level factors (total size of natural area, extent
of forest interior, extent of landform heterogeneity and geographic location), most measures of biotic diversity
(including the number of vegetation community types, provincially rare vascular plants, and regionally and locally
rare breeding birds) differed significantly among sites of private, public and mixed ownership. In general, values
at public and mixed ownership sites were greatest, with significantly lower biodiversity values at privately-owned
sites. Furthermore it would seem not to be a product of public bodies having historically purchased the largest
sites or most-forested sites, since there is no significant difference between the mean size of publically-owned and
privately-owned sites. Results of stepwise multiple regression confirm the well known relation between size of a
natural area and variation in both total, and rare species diversity. Since public sites have generally more species
than private sites, they are essential elements of any conservation network.
Introduction
Landscape ecology attends to the spatial and biological features of a region, and their interactions. Perhaps
the most important contribution that landscape ecology may make involves guidance toward land management and land-use planning. Strategic planning for
biodiversity conservation in remaining North American natural areas now recognizes the significance
of the landscape-level environment in shaping biotic
patterns. Thus decisions about the size, shape, and
distribution of natural areas tend to be placed within
a context of landscape ecology and indeed this is,
if belatedly, becoming standard practice. Patterns of
land-use and other anthropogenic factors tend to be the
major correlates of biotic diversity (Forman 1995).
A significant though little-studied factor influencing land-use is the ownership of the land (Crow et al.
1999; Kindscher and Scott 1997). Because of the
long history of private property rights in North America, plus the extensive acreages owned by aboriginal,
federal, state and provincial, and other public jurisdictions, land ownership seems likely to be a powerful
determinant of the types of conservation that take
place at particular locations in the landscape.
In a classic paper, Hardin (1968) proposed that
users of a common resource are caught in an inevitable process that leads to the destruction of an
open-access commons. This ‘tragedy of the commons’
results when publicly-owned lands are over-used by
relatively few individuals, having no regard to future
sustainability of the public resource. Yet it is not at
744
all clear that this is the case, if the resource in question is biodiversity. Ownership of habitat by private
landowners or private organizations with conservation
goals could vigorously protect the habitat on their
property from unwanted disturbances. However, in
most jurisdictions there are few regulations preventing
subsequent private landowners from converting natural habitat to a different landuse. In contrast public
jurisdictions would seem to be better able to withstand forces favoring development. Unfortunately, little data have been available to evaluate critically some
implications underpinning the ‘tragedy’ that Hardin
described. On a global scale, extensive undeveloped
land of potential conservation significance is owned
by an assortment of both public and private governing
groups, ranging from municipal to state, provincial
and federal jurisdictions (see Groves et al. 2000).
Apart from government policies, the plethora of global
property rights alone may help to explain why and
how land ownership may be a powerful determinant
of conservation.
The Niagara Escarpment Biosphere Reserve is a
largely forested, 725-km natural corridor that crosses
the most heavily populated part of Canada (Figure 1).
It supports a remarkable amount of biological diversity. Riley et al. (1996) recently published an extensive
and detailed inventory of each of the 98 Areas of Natural and Scientific Interest (ANSIs) in the Reserve
– which, collectively, constitute the core of the Reserve. However Riley et al. carried out little analysis
of the data and none at all on effects of ownership.
Our objective was to utilize the data of Riley et al.
to investigate effects of certain landscape-level factors
on biodiversity. Estimates of biodiversity (including
information about flora and fauna) were assembled for
each ANSI and effects of an array of landscape factors
(including site ownership, total size, extent of forest
interior, number of landform features, and location
effects) were evaluated statistically.
Methods
Study area
According to Riley et al. (1996) Ontario provincial
legislation (the Niagara Escarpment Planning and Development Act of 1973), established certain policy
objectives and procedures intended to protect the Niagara Escarpment in relation to aggregate extraction
and urban development. In 1985 the Niagara Escarpment Plan was adopted by the Ontario Cabinet to
address land use policies, development criteria, and
a parks and open space system, intended to protect
natural, historic and cultural features and areas along
the Escarpment. All lands within the Plan Area were
placed into one of seven land use designations (Escarpment Natural Area, Escarpment Protection Area,
Escarpment Rural Area, Minor Urban Center, Urban
Area, Escarpment Recreation Area, and Mineral Resource Extraction Area), and only strictly-controlled
development allowed within the Niagara Escarpment
Plan Area (NEPA). In 1990 NEPA was designated a
World Biosphere Reserve by UNESCO, intended as
a demonstration area for both the conservation of biological diversity and the promotion of environmentally
appropriate development.
The Biosphere Reserve supports 64% (1177
species) of the native flora of Ontario; this flora is remarkable in that so many of the native species (>70%)
are considered to be at least locally rare in one or more
of the counties or regional municipalities through
which the escarpment passes (Riley et al.1996). Three
hundred and twenty-five species of birds (72% of all
birds recorded in Ontario) have been documented in
the Reserve. Of these, 198 have shown evidence of
breeding there, 69% of the known breeding birds in the
province (Riley et al. 1996). Twenty-four of the breeding birds are considered to be provincially significant,
and 38 are forest-interior species, adapted primarily to
the special habitats of forested areas. Forty-nine native mammals, 91 native fish, 39 native reptiles and
amphibians, and 98 butterflies are also found in the
Reserve. Almost 150 faunal species are considered
to be of provincial conservation concern (i.e., endangered, threatened, vulnerable or rare) (Riley et al.
1996).
Field studies
The survey sites reviewed by Riley et al. (1996) and
used in the present project had been subject to an extensive array of detailed field studies. Some provincial
ANSIs were the subject of detailed biological inventories during the 1980’s. Additionally, many sites had
been surveyed as part of Environmentally Significant
Area (ESA) studies, natural areas inventories and wetland evaluations between 1976 and 1994. All 98 sites
were surveyed at a reconnaissance level. The level
of study at a site was determined based on existing information (e.g., vegetation community mapping,
flora and fauna checklists, etc.) Preliminary air photo
interpretation was undertaken to locate a site’s phys-
745
Figure 1. Location of Niagara Escarpment Biosphere Reserve within southern Ontario, Canada, and division of study area into five sectional
locations (Niagara Peninsula, Halton, Dufferin, Grey, and Bruce Peninsula) (after Riley et al. 1996).
iographic features and associated vegetation types.
Where access was possible, each vegetation type was
visited. A vascular plant checklist for each site was
compiled based on field observations and voucher
specimens. Breeding bird surveys were carried out
separately at the majority of sites. A great deal of field
information on the locations of rare species had been
assembled from many sources by volunteer and professional atlas projects, and accessed by Riley et al.
(1996) for site-specific information.
746
Data collection
An electronic database was created using information
available in Riley et al. (1996). We evaluated 98 sites
on the following criteria:
Size
The size (ha) of each site was estimated based on
site boundaries mapped on 1:10 000 Ontario Base
Maps (OBMs), using digital planimeter and/or a transparency grid (1 cm2 grid). Site boundaries were drawn
to contain those features for which a site had been
identified as a significant natural area, plus directly
associated areas that added to the native diversity of
the site. Boundaries fell at obvious edges between
woodland/wetlands and developed lands.
Extent of forest interior
The approximate extent of closed-canopy forest interior of each site was measured. ‘Closed canopy’ was
defined as >70% cover. Forest interior was defined as
forest occurring 100 m back from fields, other anthropogenic edges and major roads (>30 m wide), 50 m
back from minor roads, trails and road allowances
(>10 m wide), and 25–50 m back from natural edges
such as major cliff exposures, rivers and lakeshores.
Number of landform units
The total number of landform features from the representation matrix was recorded for each of the sites.
Overall, some 34 landform features were recognized
by Riley et al. (1996).
Ownership
To categorize ownership, we divided sites into private, public, or mixed (private + public) sites. For the
present purposes, if >80% of the area of a site was
privately-owned, we considered it as private. If >80%
of the area of a site was publicly-owned, we treated
the site as public. If the site did not meet these criteria
for private or public ownership, it was considered as
mixed ownership.
Number of vegetation community types
The total number of vegetation community types,
based on the vegetation classification system devised
for the Niagara Escarpment was recorded for each
site. Overall, some 38 natural community types were
recognized by Riley et al. (1996), some of which
included an array of further sub-types.
Number of vascular plant, breeding bird and reptile
and amphibian taxa
Total numbers of vascular plants, breeding birds, reptiles and amphibians were recorded for each site. The
number of mammal species was generally unavailable,
due to insufficient data from much of the study area.
‘Significant’ vascular plant, breeding bird, mammal,
reptile and amphibian species
The total number of nationally, provincially, regionally and locally rare species found in each site was
determined. Criteria for assigning status are described
in Riley et al. (1996). Mammalian top carnivores (such
as Eastern Cougar (Felis concolor), Bobcat (Lynx
rufus) and Timber Wolf (Canius lupus)) have been
essentially extirpated from southwestern Ontario.
S-ranked significant vascular plant, breeding bird,
mammal and reptile and amphibian species
We determined the total numbers of provincially rare
(i.e., S1-3) species found in each of the sites (see
NHIC [1999] for detailed descriptions of criteria).
Forest interior bird species
A composite list of forest-interior species was developed by Riley et al. (1996) from various literature
sources, including neotropical migrant forest species
declining in Ontario, forest bird species at risk and
personal observations of species occurring primarily
in forest interior.
Hawk and owl species
Hawks and owls are avian top carnivores still occurring at most sites along the Escarpment. The abundance and diversity of top carnivores may be an indicator of a more complex and supportive food chain at
a site. The number of hawk and owl species occurring
during breeding season was recorded for each site at
which breeding bird surveys had been conducted.
Endangered or threatened species
The total number of endangered or threatened species,
as defined by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), and/or the
Ontario Ministry of Natural Resources (NHIC, 1999),
were assembled for each site.
Data transformations and statistical analysis
For all data used in the present study, assumptions of
normality and homocedasticity were assessed. Biodiversity data were then log transformed [log (n + 1)]
2.770 ∗
0.54
13.5
1.71
13.3a
0.75
13.9a
1.61
16.0a
15.4a
11.0a
Size (ha)
Extent of forest
interior (ha)
Number of
landform units
0.98
380.5b,c
146.6bc
1.31
443.6 87.67 6.674 ∗∗∗
203.5 53.5
16.354 ∗∗∗
1106.9c 518.19
657.9c 317.5
74.57
40.1
500.1c
219.7bc
194.9ab 32.57
63.4b
13.56
(N = 97)
Mean SE
160.1a 27.25
24.3a
6.20
89.52
42.3
Significance
F
Overall
Bruce
section
(N = 15)
Mean
SE
Grey
section
(N = 30)
Mean
SE
Factor
There were 97 sites complete with patch size and ownership data – sizes ranged from 1 to 8049 ha. Total area
of designated natural areas was 43 472 ha, and mean
size was 443.6 ha (SE = 87.7). Furthermore, when
site 90 (Cabot Head, in the Bruce Peninsula Section;
see Figure 1) was excluded from the calculation due
to its comparatively very large size, the mean for the
remaining 96 sites was 369 ha (SE = 39.8). Results of
analysis of variance indicate highly significant differences in the mean site size, extent of forest interior and
number of landform units among the five sections (Table 1). Student–Newman–Keuls tests confirm that sites
in the Bruce Peninsula section were generally greatest
in size, though not significantly different from those
of the Grey and Halton sections. Sites in the Dufferin
section were next in mean size (and not significantly
different from the Halton section, though significantly
larger than sites in the Niagara Peninsula Section, the
smallest section of the Reserve) (see Table 1 and Figure 1). The 97 sites with information concerning the
extent of forest interior ranged from 0–4886 ha of interior forest. The overall total was 19 943 ha and the
mean forest interior size was 203.5 ha (SE=53.5). Excluding site 90 left a mean size of forest interior for
Dufferin
section
(N = 13)
Mean
SE
Size, forest interior, and number of landform units
Halton
section
(N = 14)
Mean
SE
Results
Niagara
section
(N = 25)
Mean SE
prior to analysis to achieve normality and/or homocedasticity.
ANOVAs were carried out on both the landscapelevel factors and biological features to analyze variation along a N–S gradient among the five sections of
the Reserve (see Figure 1). Student–Newman–Keuls
tests were used to evaluate differences between sections, and between sites of different ownership classes.
Stepwise linear multiple regressions were used to
compare the relative effects of landscape factors (patch
size, extent of forest interior, number of landform
units, geographic [i.e., sectional] location, and ownership) upon biotic features of each of the five designated sections of the escarpment, and for the Reserve
as a whole. Using a generalized linear model, both
continuous and categorical factors were evaluated in
the regressions. Analyses of covariance (ANCOVAs)
were carried out to detect differences in total biodiversity and rare species diversity due to ownership,
after controlling for differences in the other landscape
factors. Bonferroni post hoc tests were used to discern
differences between sites due to ownership.
Table 1. Landscape factors at natural areas in the Niagara Escarpment Biosphere Reserve, grouped by regional section, with results of ANOVA and Student–Newman–Keuls post hoc tests comparing the five sections (N = number of natural areas). Significance: ∗ = p < 0.05; ∗∗∗ = p < 0.001. Within a
factor, Student-Newman-Keuls values having the same superscript did not differ significantly (p > 0.05). (One site was excluded due to absence of data.)
747
748
the remaining 96 sites of 156.8 ha (SE=23.5). The
number of landform units per site within the Reserve
ranged from 2–27; with a mean of 13.5 (SE=0.5)
(Table 1).
Ownership
Thirty-two sites were privately owned, 24 were publicly owned, and 41 were of mixed ownership.
Landscape-level features and biotic components of
natural areas in the Reserve, grouped according to
ownership categories are given in Table 2. Privatelyowned sites had a mean total size of 250.6 ha
(SE=50.7), mean interior forest size of 110.3 ha
(SE=32.3), and contained on average 12.5 (SE=0.8)
landform units. Publicly-owned sites had a mean total size of 305.9 ha (SE=67.6), mean interior forest
of 96.7 ha (SE=23.84), and had on average 13.1
(SE=1.3) landform types. The largest natural areas
were those of mixed ownership, with a mean size of
685.6 ha (SE=197.2), mean forest interior of 343.7 ha
(SE=122.1), and a mean number of landform units of
14.5 (SE=0.8).
Analysis of variance showed significant differences in size and extent of forest interior between
the different ownership categories (Table 2). Student–
Newman–Keuls results indicate that private and public sites do not differ in either total size or extent
of forest interior, however sites of mixed ownership
are significantly larger and have more forest interior
(Table 2).
Analyses of covariance (ANCOVAs) were carried
out using site size, extent of forest interior, number
of landform units and sectional location as covariates in order to probe the effects of ownership upon
total biodiversity and numbers of significant species.
Ownership was a very significant factor in explaining
variation in the number of vegetation community types
(Table 3). Bonferroni post-hoc tests revealed that sites
of public and mixed ownership contained the greatest diversity of vegetation community types. Public
and mixed ownership sites were significantly different from private ownership sites for total diversity of
vegetation community types.
Land ownership was also highly significant in explaining variation in numbers of both ‘significant’ and
provincially rare (S1-3) vascular plant species (Tables 3 and 4). Sites of public ownership were greater
(p < 0.0001) than those of mixed ownership, and both
were significantly greater than sites of private ownership, for numbers of ‘significant’ plants. Ownership
also accounted for significant variation in numbers of
nationally, regionally and locally rare) breeding bird
species found across the escarpment (Tables 3 and
4). Sites of public ownership had significantly more
(p < 0.05) breeding birds of conservation importance
than sites of private ownership.
Effects of landscape factors on biodiversity features
Stepwise multiple linear regressions were carried out
to determine the extent to which variability in biotic
features of the Reserve were explained by site size, the
extent of forest interior, the number of landform units,
ownership and sectional location differences.
Number of vegetation community types
Size of the natural area alone accounted for nearly
50% of variation in the number of vegetation community types among sites along the escarpment length
(R 2 = 0.497; p < 0.0001) (Table 4). The number
of landform units explained a further 6% of variation
in the number of vegetation community types among
sites (p < 0.0001). Site ownership accounted for another 6% of variation (p < 0.0001), and sectional
differences a further 4%. In total, more than 66% of
variation in the number of vegetation community types
was accounted for by site size, number of landform
units, ownership and sectional location (p < 0.0001)
(Table 4).
Number of vascular plant taxa
Size accounted for 26% of variation in the number
of vascular plant taxa (Table 4). A further 10%, 4%
and 2% of variation was explained by sectional effects,
ownership and number of landform units, respectively
(p < 0.0001) of variation in the number of vascular
plant taxa explained by these four factors. Extent of
forest interior had no significant effects.
Number of S-rare vascular plants
Sectional location accounted for 11% (p < 0.001)
of variation in the number of S-rare (i.e., of provincial conservation significance) vascular plant species
in the Reserve. Size and ownership accounted for a
further 14% and 8%, respectively, totaling 33% (p <
0.0001). The extent of forest interior and landform
heterogeneity had no significant effects.
Number of ‘significant’ breeding bird species
Size accounted for nearly 39% of variation in the number of breeding birds of conservation value along the
749
Table 2. Landscape-level and biotic characteristics of the Niagara Escarpment Biosphere Reserve, plus results of ANOVA and
Student–Newman–Keuls post hoc tests comparing effects of ownership of sites (private, mixed, public) on landscape factors.
Significance: ∗∗ =p <0.01; ∗∗∗ p=0.001; n.s. = not significant. Within a factor, Student–Newman–Keuls values having the same
superscript did not differ significantly (p < 0.05).
Factor
Private ownership
(n = 32)
Mean
SE
Mixed ownership
(n = 41)
Mean
SE
Public ownership
(N = 24)
Mean
SE
F
Size (ha)
Extent of forest
interior
No. of landform
units
No. of vegetation
community types
No. of vascular
plant taxa
No. of breeding
bird taxa
No. of interior
forest bird species
No. of reptile and
amphibian species
No. of ‘significant’
faunal taxa
No. of hawk and
owl species
No. of endangered
or threatened species
No. of S-ranked
vascular plant species
No. of G-ranked
breeding bird species
No. of S-ranked
breeding bird species
No. of S-ranked
mammal species
No. of S-ranked reptile
and amphibian species
250.6a
110.3a
50.71
32.31
685.6b
343.7b
197.15
122.11
305.9a
96.7a
67.56
23.84
7.401
6.473
12.5a
0.84
14.5a
0.78
13.1a
1.31
1.236
26.7
2.8
48.1
5.0
42.1
5.5
351.8
63.8
396.8
15.5
377.3
28.8
45.1
4.0
68.2
4.1
53.8
5.2
11.6
1.1
16.8
1.3
13.1
1.5
7.6
1.1
12.4
1.0
11.2
1.5
1.6
0.3
1.9
0.3
2.3
0.5
1.9
0.5
3.3
0.4
2.3
0.4
0.6
0.1
1.0
0.2
1.1
0.22
2.8
0.5
5.5
0.7
8.2
2.4
0.0
0.0
0.0
0.02
0.0
0.0
1.3
0.3
3.6
0.7
3.1
1.0
0.1
0.0
0.1
0.1
0.1
0.1
0.5
0.0
0.5
0.5
0.7
0.0
escarpment (p < 0.0001). Ownership explained an
additional 4% of variation (p < 0.0001).
Number of S-rare breeding birds
For the Reserve as a whole, size of natural area accounted for 15% (p < 0.0001) of variation in the
number of S-rare breeding bird species. An additional
11% and 5% of the variation was explained by sectional location and forest interior, respectively (p <
0.0001).
Significance
∗∗∗
∗∗
n.s.
Numbers of reptile and amphibian taxa
Size explained 22% of variation in the number of
reptile and amphibian taxa (p < 0.0001). A further
14% and 3% of variation was explained by sectional
location and ownership effects, respectively (p <
0.0001).
Number of ‘significant’ faunal taxa
Size accounted for nearly 19% of variation in the
number of ‘significant’ faunal taxa (here amphibians,
reptiles, and mammals of greatest conservation value)
750
Table 3. Results of ANCOVA evaluating effects of ownership, with size (ha), extent of forest interior (ha), number of landform units, and sectional differences as covariates, on the biotic factors of the Niagara Escarpment
Biosphere Reserve. Significance: ∗ = p<0.05; ∗∗ = p<0.01; ∗∗∗ = p<0.001; n.s. = not significant.
Factors
MS
F -value
P -value
0.001
0.000007
0.403
0.0003
0.030
Dependent
Independent + Covariates
No. of vegetation
community types
Ownership
Size
Extent of forest interior
Number of landform units
Section
0.182
0.540
0.017
0.329
0.117
7.588
22.554
0.706
13.732
4.881
Ownership
Size
Extent of forest interior
Number of landform units
Section
0.575
0.001
0.068
0.586
0.119
7.479
0.014
0.880
7.630
1.544
Ownership
Size
Extent of forest interior
Number of landform units
Section
1.068
1.670
0.114
0.174
1.385
14.810
23.171
1.580
2.419
18.941
0.000003
0.000006
0.212
0.123
0.0004
Ownership
Size
Extent of forest interior
Number of landform units
Section
0.342
0.749
0.207
0.002
0.859
4.750
10.395
2.877
0.023
11.928
0.011
0.002
0.093
0.880
0.001
Ownership
Size
Extent of forest interior
Number of landform units
Section
0.247
1.224
0.071
0.206
0.00009
3.688
18.251
1.953
3.063
0.001
0.029
0.00005
0.307
0.083
0.970
Number of ‘significant’
vegetation community
types
Number of ‘significant’
vascular plant taxa
Number of S-rare
vascular plant taxa
Number of ‘significant’
breeding bird taxa
present on the escarpment (p < 0.0001). No other
effects were evident.
Number of hawk and owl species
Site size accounted for 16% of variation in the number of hawk and owl species (p < 0.0001). Sectional location explained a further 8% (p < 0.0001)
(Table 4).
Number of forest interior birds
Size was the only significant factor; it accounted for
32% of variation in the number of forest interior bird
species along the escarpment (p < 0.0001).
0.001
0.908
0.351
0.007
0.217
Significance
∗∗∗
∗∗∗
n.s.
∗∗∗
∗
∗∗∗
n.s.
n.s.
∗∗
n.s.
∗∗∗
∗∗∗
n.s.
n.s.
∗∗∗
∗
∗∗
n.s.
n.s.
∗∗∗
∗
∗∗∗
n.s.
n.s.
n.s.
Number of endangered or threatened species
Sectional location accounted for about 7% (p < 0.01)
of variation. An additional 12% and 5% were explained by size and ownership, respectively (p <
0.0001) (Table 4).
Discussion
Ownership
It is not clear why public ownership is associated with
high diversity, or indeed how public ownership may
have resulted in better conservation. It may be because
751
Table 4. Summary of major results of stepwise multiple regression analysis (minimum p < 0.0001)
showing effects of natural area size (SIZE), extent of forest interior (XFI), number of landform units
(LAND), ownership (OWNER) and geographic location (SECTION) on an array of biotic characteristics
for 97 sites of the Biosphere Reserve.
Biotic characteristic
Landscape factors
R2
F-value
No. of vegetation community types
SIZE
SIZE, LAND
SIZE, LAND, OWNER
SIZE, LAND, OWNER, SECTION
0.497
0.561
0.623
0.663
93.75
60.12
51.24
45.31
No. of vascular plant taxa
SIZE
SIZE, SECTION
SIZE, SECTION, OWNER
SIZE, SECTION, OWNER, LAND
0.262
0.366
0.397
0.424
33.68
27.08
20.43
16.90
No. of S-rare vascular plant species
SECTION
SECTION, SIZE
SECTION, SIZE, OWNER
0.105
0.252
0.335
11.18
15.80
15.63
No. of reptile and amphibian taxa
SIZE
SIZE, SECTION
SIZE, SECTION, OWNER
0.220
0.358
0.394
26.76
26.22
20.12
No. of endangered or threatened species
SECTION
SECTION, SIZE
SECTION, SIZE, OWNER
0.065
0.194
0.240
6.63
11.32
9.77
No. of S-rare breeding bird species
SIZE
SIZE, SECTION
SIZE, SECTION, XFI
0.148
0.356
0.410
16.48
26.01
21.51
No. of ‘significant’ breeding bird taxa
SIZE
SIZE, OWNER
0.387
0.434
59.88
35.97
No. of hawk and owl species
SIZE
SIZE, SECTION
0.164
0.240
18.59
14.88
No. of ‘significant’ faunal taxa
SIZE
0.187
21.90
No. of forest interior bird species
SIZE
0.323
45.353
of differential management or conservation measures
after the sites were included in the Biosphere Reserve,
and it may be because criteria to include sites in the
first place differed for public vs private sites. Both
these possibilities seem likely. Unfortunately there is
little information available on the previous management practices in these sites. Furthermore, despite the
fact that a common set of criteria are applied for designation of ANSI status (Area of Natural and Scientific
Interest), only a small number from the full set of criteria need be met to support status designation, and
different criteria could be satisfied at different sites.
Thus it is difficult directly to relate ownership per se
to management history at a site.
In the present study, ownership was evaluated as
a factor explaining variation in biodiversity at individual natural areas, and proved highly significant in
explaining variation in numbers of vegetation commu-
752
nity types, vascular plant taxa, S-rare vascular plants,
numbers of reptile and amphibian taxa, ‘significant’
breeding birds and numbers of endangered or threatened species. In a similar study of rare biota, LovettDoust et al. (2001) reviewed a further 340 natural
area patches across southern Ontario and showed that
public ownership was associated with significantly
greater rare species richness for birds, herpetofauna,
butterflies, mammals and plants, compared to private
ownership, after size of site was controlled.
In considering effects of land ownership on biodiversity conservation in the Biosphere Reserve, it
should be noted that sites of mixed (private + public) ownership were on average significantly larger and
more extensively forested than those of entirely private or entirely public ownership. Within these mixed
ownership sites, high total levels of biodiversity are
evident (in terms of vegetation community types, vascular plants, breeding birds and herpetofauna), and
also rare species diversity generally (e.g., provincially
and regionally rare vascular plant species, plus birds,
and hawk and owl species). Though these levels of
diversity were all significantly greater in sites of mixed
ownership than in privately-owned sites, they were not
greater than those of the significantly smaller publiclyowned sites. This suggests that while some of the best
lands (i.e., large and highly biodiverse) along the escarpment may historically have been purchased by the
provincial government or other public agencies, it remains the case that public authorities have carried out
a remit of biodiversity conservation significantly more
effectively than the host of individual private owners.
In New Zealand about 30% of that country is held
by public bodies, giving it one of the highest protected
land areas of any nation (see Norton 2000). Yet less
than 20% of lands below 500 m in elevation are part
of this conservation estate, while some 50% of lands
above 500 m are. It is estimated that 20% of threatened vascular plants occur only on private land and
another 60% occur on both public and private land,
with many having their largest populations on private
land (Norton 2000). In New Zealand over the past
decade there has been an important shift in government thinking, away from the tradition of legally and
administratively separating conservation (mainly public) and production (mainly private) lands and values
toward an approach that recognizes the importance of
better integrating these two value sets within the same
landscape (Norton 2000). Such a shift recognizes that
on non-conservation lands there is a need to recognize
the legitimate rights of private landowners to get an
economic return from their land, and also that national
responsibilities include the conservation of indigenous
biodiversity (Norton 2000).
Private ownership of natural areas may be more
responsive to economic incentives for conversion to
development (Daily and Walker 2000), especially
where natural areas and the services they provide are
not recognized as capital (because they accrue to the
‘commons’). In contrast, the greater value of land sold
for individual development would seem more likely
to influence an owner’s decision to develop or sell.
When differences in site size, extent of forest interior, landform heterogeneity and location were controlled in the ANCOVA, results indicate that the mean
numbers of vegetation community types, regionally
and locally rare vegetation community types, provincially, regionally, and locally rare vascular plants,
and regionally and locally rare breeding birds all differed significantly among sites of private, public and
mixed ownership, with biodiversity values at public
sites higher than at mixed or private sites. Hardin’s
‘tragedy of the commons’ is not evident in the Niagara Escarpment Biosphere Reserve. Indeed, though
many privately-owned natural areas exist, both the
total- and rare-species richness found in sites of public ownership far surpass those of private landowners.
Furthermore, it would seem not to be a product of
public bodies having historically purchased the largest
sites or most-forested sites, since there is no significant
difference between the mean size of publically-owned
and privately-owned sites.
Government investment in the conservation of biodiversity seems essential (see James et al. 2000). In
particular, the private sector is less well-equipped to
provide public goods related to the global environment (such as the values of biological resources). Once
provided, public goods become freely available. Furthermore, given the rate of biodiversity decline, there
is some urgency; action is necessary now and to delay action until private-sector investment is sufficiently
expanded would be hazardous (James et al. 2000).
As indicated above, mixed ownership natural areas
– including both public and private sector components
– were significantly larger and more forested than either public or private sites, and had indices of biotic
richness that were significantly greater than those of
private sites but not greater than those of public sites.
In practice, environmentally sustainable economies
are unachievable without enhanced participation of the
private sector (see Daily and Walker 2000). Business
brings much to the table of conservation: it is power-
753
ful, innovative and adaptable, and it is efficient (at least
relative to government) (Daily and Walker 2000).
Landscape-level factors
Crow et al. (1999) recently demonstrated the complexity of the relationship that exists between ownership
and land use, and the physical environment that ultimately constrains land use. These authors studied two
large plots in forested northern Wisconsin, USA and
showed that when patch size and shape were compared between ecosystems (moraine versus outwash)
but within an ownership category (private versus U.S.
National Forest), significant differences in landscape
structure were present on public land but not on private
land. On public land, different management practices
– primarily a product of timber harvesting and road
building – on different ecosystems created very different landscape patterns. In contrast, on private land the
landscape structure for different ecosystems tended to
be similar, since ownership was fragmented in both
ecosystems but on private land ownership boundaries
typically corresponded to patch boundaries. Clearly
this interaction between landscape factors and ownership and management is complex.
In the present study, five landscape-level factors
(site size, extent of forest interior, landform heterogeneity, geographic location and ownership) were
applied to natural areas along the Niagara Escarpment in an attempt to understand patterns in vegetation
communities, vascular plants, breeding birds, herpetofauna and mammals present at NAs along the
escarpment. Highly significant results from regression
analysis of these factors upon biotic diversity were evident. Though each of the landscape-level factors was
important, some figured more prominently in regard to
particular biotic groups. Given that plants and birds,
herptiles and mammals all obviously differ in their
general niche requirements and dispersal capabilities,
the effectiveness of a particular patch to their habitat
needs (in terms of size, isolation, landform heterogeneity, etc.) is also likely to differ. Different landscape constraints are likely to exist for wide-ranging
species like birds and mammals, than for herpetofauna. Similarly, large-seeded plant species (like forest
trees) are likely to be affected by landscape factors differently from small-seeded species (such as ephemeral
herbs).
Furthermore, the likelihood of species extirpation
is not expected to be uniform across taxa. Those that
are more mobile are less likely to experience local
extirpation because they can exist in small patches
and re-colonize a site (Glenn and Nudds 1989). In
contrast, species which are more rare tend to have
more specialized habitat requirements or less dispersal
ability, so they are more often extirpated (Pickett and
Thompson 1978; Cadotte and Lovett-Doust 2001). In
southern Ontario, mammals depending on large natural landscapes [including Timber Wolf, Grey Fox
(Urocyon cinereoargenteus), Wapiti (Cervus canadensis), Woodland Caribou (Rangifer caribou), Eastern
Cougar, Marten (Martes americana), Fisher (Martes
pennanti), Lynx (Lynx canadensis), Bobcat and Black
Bear (Ursus americanus)], were all extirpated from
the region by the early 1900s as extensive land clearing
occurred (Larson et al. 1999).
In a recent study of landscape and fragment size effects on reproductive success of forest-breeding birds
in Ontario, Burke and Nol (2000) monitored nesting
success of five species of songbirds on 40 fragments
(12–2350 ha in total woodlot size) and two contiguous forest sites in south-central Ontario, from 1994
through 1997. Woodlot size was the most important
variable contributing to differences in reproductive
success, with local forest cover (within a 10-km radius) having no significant additional effect on productivity for any species. For all species except one, adult
female reproductive success was at or above replacement levels in large fragments (mean of 121 ha core
area, 849 ha woodlot area) and continuous forest, and
below replacement levels in small fragments (mean of
7.8 ha core area, 93 ha woodlot area).
In their study of the mostly forested sites along
the Niagara Escarpment, Riley et al. (1996) surveyed
breeding habits for 38 forest interior bird species.
Sites having <100 ha of forest interior averaged c. 14
species per site; sites with >300 ha of forest interior
averaged 34 species. According to Riley et al., woodland sites along the escarpment have essentially no
forest interior left when they are smaller than 50 ha
(based upon correlations of size of forest interior and
number of interior bird species) or smaller than 92 ha
based on correlation of total site size and size of forest
interior. In contrast to this effect for birds, Weaver and
Kellman (1981) found for plants no effect of area or
isolation on tree species persistence in southern Ontario older-growth forests. However it should be noted
that tree declines tend to be difficult to document due
to the longer lifespans of trees and generally weak
historic data (Larson et al. 1999).
From the perspective of land managers trying to retain maximum biodiversity, it should be noted that site
754
size was the single most significant landscape-level
factor in explaining both total and rare species diversity for vegetation community types, vascular plant
taxa, herpetofauna, and birds (see Table 4). Larger
sites contained greater biodiversity of both common
species (plants) and rare species (all groups except
mammals). Variation in rare mammal species along
the escarpment was not significantly accounted for by
any of the landscape-level factors. This may be due to
their overall extreme rarity and a paucity of data, in
that very few species were found in any of the sites,
or simply to the fact that the landscape-level factors
we evaluated were not among those that influence rare
mammal diversity.
At present the largest intact patches of forested
land in southwestern Ontario are publically owned,
under the jurisdiction of the Ontario Government’s Ministry of Natural Resources (Pearce 1993).
Privately-owned lands are the most fragmented, comprising highly isolated woodlots, and thus providing
less protection for a wide variety of species (Pearce
1993). Along the landscape of the Niagara Escarpment
there was no significant difference observed in the
sizes of patches of privately- and publicly-owned land.
Thus other factors must account for the greater diversity values observed on the Escarpment’s public lands.
Our observations support the conclusions of Pearce
(1993) and also those of Thomas et al. (1997) who
determined that old woodlands (>400 yr) in Britain
experienced significantly more effective management
(with respect to nature conservancy) when they were
on publicly- and trust-owned lands, than when they
occurred on private- and estate-owned lands. There
is clearly more to conservation and biodiversity than
species richness alone. For example, it could be that
the private sites have fewer species, but have different
species (i.e., they may complement other, larger sites).
Possibly private sites act as ‘stepping stones’ in otherwise heavily-fragmented landscape, connecting larger
sites. Perhaps too they protect scattered, rare habitats
in otherwise biologically-poor landscape.
In the conservation of biodiversity along the Niagara Escarpment, identification of biotic measures that
seem most sensitive to landscape-level factors could
help to focus conservation efforts on both public and
private lands. Within the Biosphere Reserve three features stand out as potential indicators – the number
of vegetation community types, total vascular plant
diversity, and the number of S-rare breeding birds.
High diversity values for each of these features were
present. The number of vegetation community types
seems particularly useful as it can be quantified readily by experienced land managers using simple visual
cues. Likewise, the number of S-rare (or regionally
rare) birds also has a highly significant amount of its
variation explained by landscape-level factors and is
relatively easy to estimate, given the general abundance of excellent records of birders visiting natural
areas. In contrast, total vascular plant diversity, though
having a significant proportion of variance accounted
for by landscape-level factors, may be less practical as
a measure for natural area managers. Identifying all of
the vascular plants of a natural area requires extensive
research by botanists, and could be less cost-effective.
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