Download biodiversity - City of Mitcham

biodiversity
“Settlements surrounded and connected by native plants,
buzzing with the sounds of birds and frogs and a
multitude of tiny living things. Bilbies and bettongs in
every primary schoolyard. Council and local research
institutions working together toward a sustainable
future.”
City of Mitcham Community Visioning Forum, December 1998.
Biological diversity, or biodiversity, refers to the variety of life-forms:
plants, animals and micro-organisms, the genes they contain and
the ecosystem of which they form a part.
An ecosystem refers to the complex networks formed by the
interactions of species in a given area with each other and with their
environment.
Biodiversity should be considered at three distinct levels:
— ecosystem diversity
— species diversity, and
— genetic diversity.
To accurately track biodiversity in the City of Mitcham, indicators of
biodiversity should be developed at each of these levels.
WHY IS BIODIVERSITY IMPORTANT?
The Commonwealth State of Environment Report (1996) points out
that biodiversity is important for four reasons:
ƒ
Healthy ecosystems make all life possible; they maintain the
quality of the air we breathe, they maintain and regulate the
climate, fresh water, soil formation, recycling and disposal of
wastes.
ƒ
It is ethically wrong for one species or generation to use the
Earth’s resources exclusively for their own use.
ƒ
Many Australians place a high aesthetic and cultural value on
native plants and animals. They are essential to our sense of
cultural identity, spiritual enrichment and recreation.
City of Mitcham State of Environment Report
11
ƒ
Biodiversity is also of economic importance through the control
of pest plants, animals and diseases, the pollination of crops,
and the provision of building materials, medicines and tourism.
Increased vegetation covering also helps to combat global warming
through sequestration of greenhouse gases.
The Commonwealth report concludes that: ‘future generations are
unlikely to forgive further losses of biodiversity through bad
management or lack of commitment, especially now that its
precarious state is recognised’.
MEASURING BIODIVERSITY
PRESSURE
PEST PLANTS AND ANIMALS
This indicator provides a measure of distribution and abundance of
those introduced plant species causing significant problems of
posing significant threats.
Since colonial days the City of Mitcham has been colonised by a
range of introduced plant and animal species which, without natural
competitors, parasites and diseases have placed great pressure on
the biodiversity of the area.
The severity of pest plant infestation can be affected by several
factors including: growth patterns, habitat and adaptability to
receiving environments, soil types, rainfall, shaded areas and water
ways. The olive is one such plant that has adapted readily to the
hills environs around Adelaide.
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City of Mitcham State of Environment Report
SEVERITY OF PEST PLANTS INFESTATION : CITY OF MITCHAM
1992 – 1998
GROUP
Trees
Shrubs
Ground
covers,
grasses
COMMON NAME
BOTANICAL NAME
SEVERITY
RATING
0–5
(5 = most
severe)
5
4
4
3
3
5
5
2
2
4
2
2
3
4
5
5
5
4
2
3
3
4
Olives
Buckthorn
Tagasaste
Aleppo pine
Azzarola
Desert ash
Montpellier Broom
Hedge Broom
Scottish Broom
Topped lavender
Sweet Briar
Dog Rose
Milkwort
Bamboo
Pampas Grass
Blackberry
Boneseed
African daisy
Hemlock
Boxthorn
Olea europeaea
Rhamnus alaternus
Cytisus proliferus
Pinus halepensis
Crataegus sinaica
Fraxinus oxycarpa
Genista monspessulana
Cytisus racemosus
Cytisus scoparius
Lavandula stoechas
Rosa rubiginosa
Rosa canina
Polygala myrtifolia
Arundo donax
Cortaderia selloana
Rubus ulmifolius
Chryanthemoides monilifera
Senecio pterophorous
Conium maculatum
Lyciium ferocissimum
Crassula
German Ivy
Osteospermum
Gazania
Common Ivy
Field bindweed
Tangier pea
Nasturtium
Periwinkle
Horehound
Tricolour harlequin
flower
Bubil watsonia
False hair grass
Fountain Grass
Petty spurge
Kikuyu
Senecio mikanioides
Osteospermum fruticosum
Gazania spp
Hedera helix
Convolvulus arvensis
Lathyrus tingitanus
Tropaeolum majus
Vinca major
Marrubium vulgare
Sparaxis tricolor
3
4
4
3
3
3
2
4
4
Watsonia bulbillifera
Pentaschitis airoides
Pennisetum setaceum
Euphorbia peplus
Pennisetum clandestinum
5
3
3
3
2
Source: Compiled by David Deer, Horticultural Consultant, City of Mitcham
Note1:
Native vegetation introduced from other States can also be considered
weeds in some locations. A list of these plants is currently being
compiled.
Note2:
This table rates pest plants according to the severity of current and
potential impact on the biodiversity of the City.
City of Mitcham State of Environment Report
13
How Are We Doing?
The data shows that weed infestation is a major threat to
biodiversity in the City.
The effects are seen most clearly adjacent waterways, with almost
the total length of watercourses affected to some degree. Much of
the original native vegetation in these areas has been lost or
replaced by weeds (PCWMB 1998a).
Native fauna also faces significant pressure from introduced plants
and animals.
Cats (domestic and feral), rabbits and foxes are also are an
acknowledged concern although specific numerical data is not
available. A cat-by law has been proposed by Council (January 1999)
and is awaiting Parliamentary approval.
A high land consumption rate can also place pressure on natural
habitats and threaten biodiversity (Commonwealth, 1998b). Urban
density and land use indicators are discussed in the Land
Management Chapter of this report.
CONDITION
NUMBER OF THREATENED SPECIES
This indicator is a good measure of species diversity and indicates
which groups may need special management.
THREATENED SPECIES SIGHTED WITHIN THE CITY OF
MITCHAM 1992 -1998
Major Group
Vegetation
Animals
14
Species
Ferns
Native Pines
Trees/Shrubs
Grasses
Birds
Reptiles, Mammals, Amphibians
Butterflies
Number of
Threatened Species
2
2
41
19
12
insufficient data
1
Note 1:
For full lists of these species, their conservation status, and sources of
this data, refer to Appendices 5-8.
Note 2:
The data should be interpreted with care because increases in species at
risk can be attributed to increased knowledge of species that were already
at risk.
City of Mitcham State of Environment Report
How Are We Doing?
The data shows that the City of Mitcham is in a unique position to
aid the protection and enhancement of native flora and fauna
species.
It is also important to note that species diversity is closely linked to
ecosystem diversity.
The retention of plant associations or communities is as important
(or more important) as protecting specific species. In this area, too,
the City of Mitcham can play a vital role in preserving communities
of threatened vegetation.
The City contains some of the last remaining examples of
eucalyptus microcarpa (grey box) woodland in the State. These
woodlands have been given a high conservation priority rating by
the State Environment Department (Neagle 1992).
Although one species of butterfly is threatened, eight species have
become extinct within the City limits. The retention of caterpillar
foodplant for the threatened butterfly species will ensure its survival
in Micham, but more importantly, the planting of foodplants and
nectoring plants for the ‘extinct’ species may provide suitable
habitat for these species to re-establish.
AREA OF NATIVE VEGETATION AS A PERCENTAGE OF TOTAL
COUNCIL AREA
This indicator is the best available measure for the condition of
ecosystem diversity.
The best available data shows:
Area of City of Mitcham
Area of (Overstory) Native Vegetation (1986)
Native Vegetation as percentage of total area
City of Mitcham State of Environment Report
7468.5ha
1734.83ha
23.23%
15
Native Vegetation
Vegetation heritage agreement
NPWS reserve
City of Mitcham boundary
Major Road
Minor Road
Source: Planning SA
Note 1: Although the native vegetation data dates from 1986 it is included as a
baseline for future reference. Improved satellite mapping systems will
enable more regular assessment of this indicator.
Planning SA will
complete a similar but more extensive mapping of native vegetation by mid1999.
Note 2: Data refers to tree canopy only, it does not reflect the quality of native
vegetation, particularly as regards weed infested areas. Nor does it
reflect the degree or quality of understory vegetation.
How Are We Doing?
The available data shows that Mitcham has a relatively high
percentage of native vegetation in comparison to most metropolitan
Adelaide Councils.
Changes in this indicator will reveal the success or otherwise of
strategies to enhance native vegetation in Mitcham.
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City of Mitcham State of Environment Report
RIVER HEALTH
‘River health’ is a concept that goes beyond suitability of water for
particular uses and integrates a range of ecosystem values and
functions. (ANZECC 1998). It is a good measure of ecosystem
diversity.
A one off testing project of water animals (aquatic
macroinvertebrates) and plants (aquatic microphytes) was done by
Professor W.D Williams in April 1996. The project was intended as
an overall indication of ecological condition. A scale of 0-5 was used
to rate the ecological condition.
Summary of Biological River Health Sampling Points
April 1997
River Name
Sturt River
Brownhill Creek
Sampling Point
Ecologocial Status
(5 High 0 Low)
Stirling (Pole Road)
3
Coromandel Valley
(Frank Smith Park)
3
Coromandel Valley
(Murrays Hill Road)
4
Bedford Park
(Caravan Park)
4
Bedford Park
(upstream of Sturt Road)
4
Brownhill creek
(upper reaches)
1
Brownhill creek
(caravan park)
1
Torrens Park
(Mitcham Reserve)
1
Hawthorn
(Memorial Gardens)
0
Source: Patawalonga Catchment Water Management Board (1997a)
Note 1: Further sampling of macroivertebrates was carried out at five sites during
preparation of the BCEAP (1998). Results broadly supported Professor
Williams’ work.
Note 2 This indicator is strongly linked to the catchment management indicators
discussed in the Chapter 3.
City of Mitcham State of Environment Report
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How Are We Doing?
As a result of the above sampling, the PCWMB (1997a) reached the
following conclusions about the health of the two main watercourses
in the City of Mitcham:
“…for most of the course of the (upper) Sturt River has a
relatively diverse and abundant macroinvertebrate fauna, …
not too far removed from pre-European status. There seems
little doubt that this reflects the protection offered by the Sturt
Gorge Recreation Reserve in the middle reaches and the still
relatively undeveloped nature of the upper part of the
catchment.
“Brownhill Creek [is] in poor condition … virtually insignificant
amounts of aquatic life exist.”
RESPONSE
NUMBER AND SIZE OF PROTECTED AREAS
Protected areas are necessary, although alone are not sufficient, to
enhance biodiversity at all levels.
State or Commonwealth Protected Areas in City of
Mitcham, 1998
Area (Hectares)
Belair National Park
828.61
Brownhill Creek Recreation Park
Shepherds Hill Recreation Park
Sturt Gorge Recreation Park
Private Land (Heritage Agreements)
Saddle Hill Reserve
Watiparinga Reserve
Blackwood Hill Reserve
TOTAL
50.84
77.12
32.40
1.17
15.90
24.10
60.00
1090.14ha
Source: Planning SA, City of Mitcham Horticultural Consultant
Note 1: Data does not include 200ha State government land at Craigburn farm. It
is intended that this land will be incorporated into the Sturt Gorge Recreation Park.
Note 2: Data does not include bequests and institutional land at Waite, Flinders
University and CSIRO.
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City of Mitcham State of Environment Report
Total Number, Council Reserves, Parks, Gardens, Sport
and Recreation Areas, 1999
Ward
Boorman
Gault
Overton
Babbage
Craigburn
Park
Number
30
32
22
52
46
24
206
TOTAL
TOTAL AREA : COUNCIL MANAGED PUBLIC GREEN SPACE
CITY OF MITCHAM 1999
WARD
Boorman sport and recreation
Boorman parks and gardens
Gault sport and recreation
Gault parks and gardens
Overton sport and recreation
Overton parks and gardens
Babbage sport and recreation
Babbage parks and gardens
Craigburn sport and recreation
Craigburn parks and gardens
Park sport and recreation
Park parks and gardens
TOTAL (square metres)
TOTAL (hectares)
AREA (square metres)
88,960
1,093,702
115,350
69,560
78,388
40,102
73,662
756,574
781,369
651,058
65,660
1,072,587
4,886,972
488
Source: Council records, City of Mitcham Horticultural Consultant.
Note 1:
Improved access to geographic information systems and aerial
photography
interpretation
techniques
will
enable
improved
representation of this data in future, and provide a useful tool for
planning vegetation corridors to enhance biodiversity.
Note 2:
This indicator is closely linked to land management indicator ‘council –
managed open space’.
How are we doing?
The data shows that there is great scope for increasing the amount
of native vegetation within protected areas. Comparison with more
current information being collated by Planning SA and Council will
reveal if these opportunities are being pursued effectively.
The data also shows significant areas of native vegetation outside
protected areas. Changes in this data will show how effectively
Council and the community are revegetating non-protected areas
with native plants.
City of Mitcham State of Environment Report
19
PARTICIPATION IN BIODIVERSITY PROJECTS
Bushcare
A good medium term measure of the success of strategies to
enhance biodiversity will be the level of community awareness and
support for biodiversity projects.
Although difficult to quantify, growing participation in projects like
Bushcare show what can be done in this area. Managed by ‘Trees
for Life’ and partly funded by the City of Mitcham, the Bushcare
project involves community members in caring for specific sites of
native vegetation. The project has grown steadily in recent years.
Growth of the Bushcare project in the City of Mitcham
Bushcare Sites
Bushcarers
94/95
95/96
4
13
10
42
96/97
97/98
17
55
20
61
98/99
21
62
Source: Andrew Allanson, ‘Trees for Life’
Leafy Seadragon-Friendly Catchments Project
Participants include the Coromandel Valley Community Association,
Coromandel Valley Primary School, Mitcham and Onkaparinga
Councils, the Patawalonga Catchment Water Management Board and
Greening Australia.
Through revegetating the riverine environment of the Sturt River, the
project promotes links between land-based activities and the marine
environment. Poor water quality outflows to the sea and cause
sedimentation of seagrass beds.
The project is located along the Sturt River, upstream of the Frank
Smith Dam, and involves weed control and revegetation with local
indigenous aquatic and terrestrial plant species.
The locally threatened species, the Leafy Seadragon, is used to
highlight the loss of marine habitat due to pollution of inland
waters.
Council Biodiversity Projects
Council is working on several projects to enhance biodiversity in the
City. These include:
•
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an aerial photography mapping project, detailing more
accurately the extent of overstory native vegetation in the City.
City of Mitcham State of Environment Report
•
in partnership with the PCWMB and the Natural Heritage Trust, a
Biodiversity Action Plan for the Sturt river which will address
water quality, hydrology, land use issues, catchment ecology,
and native flora and fauna species.
•
in partnership with the PCWMB and the community, a removal
program for introduced vegetation along Brownhill Creek.
How Are We Doing?
The data suggests there is increasing knowledge within the
community about the importance of protecting and enhancing
biodiversity. Much remains to be done, however, to actively address
the pressures in this area.
City of Mitcham State of Environment Report
21
What Can I Do?
ƒ Plant species native to the area from
locally collected seed (obtain a list of plant
species from DEHAA, or phone Trees for
Life for advice, 8207 8787)
ƒ Obtain from Council a copy of non-native
species to avoid when planning a garden.
ƒ Become involved with a biodiversity
program, like Bushcare.
ƒ Control weeds on my property, being
careful to keep chemicals out of creeks and
waterways.
ƒ Keep my cat within my property
boundaries inside the house at night.
ƒ De-sex my cat.
ƒ Have my cat wear a bell.
ƒ Keep my dog on a leash and under
supervision.
ƒ Plant nectoring and caterpillar foodplants
(check out foodplants at website,
http://www.adelaide.net.au/~reid)
ƒ Retain species which provide habitat or
food for native fauna.
ƒ If trees must be felled, provide alternative
habitat such as nesting boxes for birds.
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City of Mitcham State of Environment Report
What Can Council Do?
Develop and implement an Environmental Action Plan
to meet the following objectives:
9
Control pest plants and animals that are a threat to our
environment.
9
Identify and protect threatened species.
9
Maximise retention of native vegetation.
9
Offset essential clearance with revegetation of
indigenous species.
9
Identify, protect and enhance significant habitats and
corridors.
9
Develop an appreciation among Council and the
community of the importance of native vegetation.
City of Mitcham State of Environment Report
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City of Mitcham State of Environment Report