Urban Restoration
the advantages and challenges
Catherine Bryan
Tena koutou katoa,
Ko Pukenui o raho toku maunga
Ko Tairongo toku moana
Ko Waiotahe toku awa
No Ohiwa ahau
Kei Kirikiriroa toku kainga inaianei
Ko Catherine toku ingoa
Ka huri ahau inaianei, ki, te reo tauiwi
A very good afternoon to you all,
My name is Catherine, I am a research support staff member in the Environmental Research Institute at the University of Waikato. I live in Hamilton but I’m from Ohiwa, here in the Bay of Plenty and today it is my great pleasure to talk about the advantages and challenges of Ecological Restoration in an urban environment.
1
Introductions
The underlying science
Why work in urban ecosystems
Restore or Reconstruct?
The Goals
The Challenges
The Advantages
2 Case Studies
Tena koutou katoa,
Ko Pukenui o raho toku maunga
Ko Tairongo toku moana
Ko Waiotahe toku awa
No Ohiwa ahau
Kei Kirikiriroa toku kainga inaianei
Ko Catherine toku ingoa
Ka huri ahau inaianei, ki, te reo tauiwi
A very good afternoon to you all,
My name is Catherine, I am a research support staff member in the Environmental Research Institute at the University of Waikato. I live in Hamilton but I’m from Ohiwa, here in the Bay of Plenty and today it is my great pleasure to talk about the advantages and challenges of Ecological Restoration in an urban environment.
2
Research Support Officer
Terrestrial ecology
•Forests
•Epiphytes
•Restoration
My background is in terrestrial ecology – I have done most of my study and work in lowland forests of the North Island. I did my MSc research on epiphytes and their ecology in urban forests – trying to discover why many epiphyte species are missing from urban forests. All of my work is focussed towards ecological restoration and I have been part of the urban restoration team at the University of Waikato for three years. I am involved in a few community initiatives including Tui 2000 and the Waikato Biodiversity Forum. 3
At the Environmental Research Institute we have a two pronged focus – research and consultation. Our staff members do research in terrestrial, feshwater, coastal and antarctic ecosystems. I am part of the terrestrial team and have worked with councils, community groups and individuals on restoration issues. A few examples of the work we do are 4
These reports on the environmental effects of the only ski field on Mt. Taranaki, the coastal walkway impact in New Plymouth, 5
The threatened and special plants of the Taranaki region, the Ecology of Barrett Domain, 6
And an interactive planting plan for Hamilton’s Waiwhakareke Natural Heritage Park. 7
Bare,
disturbed
earth
Colonisers
e.g. mosses,
grasses
Early‐arrival
species e.g.
tutu, tea tree
Mid‐arrival
species e.g.
ferns,
Coprosma
Late‐arrival
species e.g.
tree species
Functional
forest
community
All of our work and advice is based on ecological theory because following natural patterns in terms on plant assemblage and interactions has been shown to reap the best rewards. This diagram represents a key theory that we follow which is ecological succession. It is an important concept for the rest of my talk so I’ll walk you through it. This diagram explains the progression through different successional groups as a natural ecosystem like a forest establishes after disturbance.
8
Bare,
disturbed
earth
Colonisers
e.g. mosses,
grasses
Early‐arrival
species e.g.
tutu, tea tree
Mid‐arrival
species e.g.
ferns,
Coprosma
Late‐arrival
species e.g.
tree species
Functional
forest
community
Age 0 years Age 200 years
Image:
Lucas Frey
So first up we start with disturbance event such as fire, human activity, flooding or pollution. Conceptually this creates a blank canvas although in reality we often have an environment with foreign components such as weeds or pollution to deal with first. On this graph at the top we have a high proportion of group 1 which is bare, disturbed earth which is too harsh for the establishment of any trees or shrubs. Instead, colonising plants arrive and move the system to stage 2 where communities of plants like grasses or mosses establish and begin to ameliorate the harsh conditions by accumulating moisture, stabilising soils and fixing nitrogen. The next stage involves early‐arrival species such as tutu and tea tree which further improve the microclimate and conditions by creating shade, increasing humidity, and further ameliorating the environment. As these species establish they will out‐compete species from the two previous groups so you can see on this graph that one group peaks at the expense of the other. So succession is not the accumulation of species but the replacement of each functional group with another.
Stage 4 sees mid‐arrival species like coprosma species and ferns arrive once a canopy of the previous species has established. This is where the community really begins to increase in diversity and structure. We begin to see the development of an understorey and groundcover. However, it is not until stage 5 that dominant tree species begin to arrive and the community begins to develop complexity and host many different species and groups of plants. Stage 6 represents a mature or functional state such as a mature forest. You can see up the top that early groups become more prevalent here again. This is because we are always dealing with a dynamic system where disturbance events, large or small, continue to occur and provide opportunities for these earlier groups to again play their role. A simple example of this is tree fall in a forest that creates a canopy gap and 9
New planting 2 years
5 years
11
20 years
Waiwhakareke sequence, canopy closure, bare ground, poineer death, enhancement planting‐ McKay story. Threshold for self‐sustaining regeneration; e.g. liz’s work
12
40 years
We also know from the pioneering work of people like Alwyn Seeley, Peter Morris and Alison Edgar that it is possible within 20 years to have a good canopy cover of native trees established in a gully setting.
13
Mature
www.teara.govt.nz/en/map/23596/forest‐cover‐before‐human‐habitation
www.teara.govt.nz/en/map/15842/pastoral‐land‐use
Our native ecosystems are not evenly distributed across landforms
16
So any native ecosystems that we have in urban areas – which are always in lowland areas – are very valuable because they represent very rare lowland ecosystems
17
Many of these ecosystems are
degraded
What we should have had here: Kahikatea semi‐swamp forest with an array of native grasses, sedges and reeds in the waterlogged areas. What we do have here: Grey willow, arrum lily, macrocarpas and wandering jew
18
Restore
Reconstruc
t
There are three main ways that people approach planting native species. The first is revegetation, now I realise that these are pine trees in a xmas tree farm but it’s the closest photo I could get. Revegetation is where a few species are planted with the objective of filling in the landscape. They are generally not planted with a view to the long term and are the most likely to be planted then left. Restoration is undertaken where there is some native components remaining while reconstruction is undertaken when there are no remnants of native ecosystems at all. 19
Ecological Restoration
“intentional activity that initiates or accelerates the recovery of an ecosystem with
respect to its health, integrity and sustainability”
So on the theoretical scale restoration occurs somewhere around here and is defined as “intentional activity that initiates or accelerates the recovery of an ecosystem with
respect to its health, integrity and sustainability”
This is what most community groups in the north island do and as I’m sure you are aware, looks a bit like this
20
Ecological Restoration
Age 0 years Age 200 years
Image:
Lucas Frey
21
Ecological Restoration
Ecological Reconstruction
“intentional activity that initiates or accelerates the establishment of a native
ecosystem where there was none before”
In contrast, ecological reconstruction starts at this end of the spectrum and can be identified as intentional activity that initiates or accelerates the establishment of a native
ecosystem where there was none before”
And it looks more like this
23
Ecological Reconstruction
Ecological Reconstruction
Overarching Goals
To improve:
•ecosystem biodiversity, function, resilience and
services
•environmental aesthetics, educational
opportunities and people’s connection with
nature
Regardless of which practise you are undertaken, the overarching goals are normally to 26
Urban Restoration
the advantages and challenges
Catherine Bryan
So we have moved on to the advantages and challenges – as per the title of this talk. However, because it is always good to finish on good news I’ve decided to discuss the advantages last. This section of the presentation will hopefully make you realise that there are some very good reasons to do urban restoration and I’d be happy to discuss any potential urban sites in your area after this session.
27
The Challenge:
Working with Disturbed Ecosystems
Fragmentation
Losses
Gains
So the challenges of urban restoration can be summed up and they all come down to the fact that you are working with a very disturbed ecosystem. Sometimes this means a small fragment of forest, an urban stream, or a in some situations, a landscape where every native component has been completely removed. 28
Reference Ecosystem?
Fragmentation
29
Edge Effects & Habitat Loss
Fragmentation
30
Edge Effects
Fragmentation
31
Species loss
45%
absent
in urban
forests
Epiphyte species
Pyrrosia eleagnifolia
Asplenium flaccidum
Microsorum pustulatum
Metrosideros fulgens
Blechnum filiforme
Collospermum hastatum
Earina mucronata
Astelia solandri
Metrosideros perforata
Asplenium polyodon
Freycinetia banksii
Hymenophyllum sanguinolentum
Earina autumnalis
Microsorum scadens
Winika cunninghamii
Griselinia lucida
Tmesipteris tannensis
Ripogonum scadens
Lygodium articulatum
Muehlenbeckia australis
Ichthyostomum pygmaeum
Asplenium oblongifolium
Metrosideros diffusa
Collospermum microspermum
Drymoanthus adversus
Parsonsia heterophylla
Leucopogon fasciculatus
Pittosporum cornifolium
Urban
Non-urban
Loss
32
Species gain
Carolyn King
N. Lawes
D. Mudge
D. Mudge
Gain
33
Vandalism, litter & safety concerns
Also…
34
Ongoing pressure
And the major difference between urban and non‐urban sites is that the urban sites are recipients of ongoing pressure – with people surrounding the fragment there is always going to be disturbance and most of these challenges need to be managed as they can’t be eliminated.
35
Predator-proof fence?
Predator‐proof fence
36
The Challenges:
working with disturbed ecosystems
• Fragmentation
• Losses
• Gains
The Advantages:
• Taonga
• Proximity to people
Taonga
•Biodiversity
•Ecosystem services
•Habitat & resources
A sample of what was – and with that, a treasure chest for biodiversity as well as the
associated ecosystem services. For example – water filtering and soil protection. With that the ecosystems provide habitat and resources such as food, nesting materials and water for our native fauna.
38
Proximity to people
www.arapawagoats.org.nz
permuted.org.uk
www.123rf.com
www.kiwicare.co.nz
Although we have a pest problem in urban areas with mice, cats, possums and rats this isn’t actually that bad because being in an urban setting means that we don’t have other pests like goats, deer, very many stoats or rabbits. Of course this varies between cities but as a rule we have a pest sub‐set.
39
Proximity to people:
Care of threatened species
B. Clarkson
media
B. Clarkson
W. Clarkson
media
Botanic gardens and zoos
40
Proximity to people:
Intensive management
Workforce
Easy access
42
Recreation
Haibtat
43
Community-building
Haibtat
44
Health & wellbeing
Haibtat
45
Aesthetics
And property value
46
Education & awareness
Urban residents
Local experts
Natural
environment
And property value
47
Rebecca Martin
Mike Clearwater
“Providing a wellinformed public
could be the most
important
application of
urban ecology”
McKinney 2002
Case Study One
Hamilton City Gully Restoration
Hamilton Ecological District
native vegetation = 1.6% of total
area
–
–
–
–
–
Primary forest - 0.2%
Wetlands - 0.4%
Secondary forest - 0.6%
Logged forest - 0.4%
At least 15% flora locally
threatened or locally extinct
– Up to half of bird species extinct
or locally extinct
; on a par with the worst examples in NZ and the world:
54
Gully Restoration Programme
Shifting the balance from exotic species to
native dominance
Mainly early successional work
Aim:
•Raise public awareness and appreciation of Hamilton's gully systems
•Actively promote and enable the physical restoration of this resource.
55
Original Gully Vegetation
Gully Guide
Vegetation in restored vs. control
– percent cover
Although funding and involvement from the council has varied, the programme has created a community of like‐minded, motivated residents who between them have a large pool of energy and practical knowledge.
57
Real change
Control
Early succession
Mid succession
The Gully Restoration Programme was established as a partnership between Hamilton City Council (HCC) and the local community. The aim of the programme is to raise public awareness and appreciation of Hamilton's gully systems, and actively promote and enable the physical restoration of this resource. The programme was developed in association with the Environmental Protection Overlay (est. 1987), which applies specific rules to areas of the city with gullies. These rules acknowledge the importance of gullies in the city and provide a baseline to manage the impacts of development. The programme has included a range of initiatives: the development of the Gully Restoration Guide, distribution of newsletters, holding gully workshops, and the Plants for Gullies programme. 58
Native regeneration
Case Study Two
Waiwhakareke Natural Heritage Park
•
•
•
•
Est. 2004
60 hectares, inc. 10 ha peat lake
Pasture to forest
Following successional framework
Top: 2007 G. Kelly, Bottom: 2012 C. Bryan
61
2004
2009
2010
2012
Lessons learnt
•Early arrival plants ameliorate conditions
for later-arriving species
•Mulch is crucial for survival in droughtprone areas
•Dense plant spacing improves growth
rates, canopy cover and supresses weeds
To wrap up
Urban ecological restoration is an exciting
way to repair our natural environments
There are many benefits to working in urban
settings
Following ecological theory will maximise
the success and scope of restoration efforts
Thank you!
Acknowledgements:
Environmental Research Institute,
Peter Huggins, conference organisers and sponsors.
[email protected]