Communities and habitat

Healthy functioning ecosystems are a fundamental element of healthy functioning landscapes. They are valuable in themselves and provide ecosystem services such as air and water quality; carbon sequestration; and habitat, amenity and cultural values. Biodiversity is an important part of ecosystem functioning and any further losses are unacceptable for future generations.

A major threat to lowland grassland and woodland communities is from the continued spread of urban development, particularly for housing. This threat is exacerbated by the strong economic position of the ACT as people continue to prefer large houses on separate blocks of land either in the ACT or in neighbouring NSW.

Demand for housing is also being driven by a growing population and a declining number of people per household so that the rate that new households are formed is increasing. From a perspective of controlling the consumption of raw land, housing demand must take denser forms and include more redevelopment of existing housing.

Weeds are also of concern to both biodiversity and agricultural values particularly following the 2000 to 2006 drought and 2003 bushfires. Weeds such as Pattersons curse, capeweed and nodding thistle have become established on the newly bare ground that has followed loss of introduced pasture and native plants through fire and drought. Other weeds (e.g. Chilean needle grass [Nasella neesiana] and African love grass [Eragrostis curvula]) are also spreading in any places where the land has been disturbed particularly along fire trails, utility easements and adjacent to urban areas. Other weeds include willow, broom and some water weeds.

Pests such as oriental weatherloach (Misgurnus anguillicaudatus) and European wasp (Vespula germanica) are increasing their hold in urban and other areas, although recent data compiled by Canberra Ornithologists Group indicate that the common myna (Acridotheres tristis) may be decreasing in abundance in the urban areas of Canberra (Canberra Ornithologists Group 2008). Feral horses have migrated from the Snowy Mountains into the ACT following the bushfires and removal of dense vegetation.

Natural values along with urban areas need to be protected from bushfires. Key areas for protection have been identified and appropriate management for biodiversity outcomes is being
implemented.

Recent positive moves to limit threats to biodiversity have included:

• reducing (but not eliminating) land development in relatively undisturbed woodlands and grassland areas by increasing the rate of urban infill in areas that are already degraded, redeveloping burnt pine plantations and moving to a smaller block size in new developments
• changing the location of Gungahlin town centre to reduce threats to habitats of threatened species
• developing land management agreements that enable farmers and biodiversity specialists to work together in rural areas and
• increasing the area protected by nature reserves.

Endangered species and communities

In the ACT, two ecological communities, and 17 plant and animal species are endangered; a further 14 species are vulnerable. The number of endangered and vulnerable species is increasing.

• Yellow Box-Redgum Grassy Woodland is habitat for eight threatened species and other woodland species that are described as declining.
• Natural temperate grasslands are under considerable threat as are a number of threatened and declining species that live in the grasslands.
• Woodland birds and native fish are both in decline.
• Five native fish are threatened or endangered particularly from reduced flows and quality of water in rivers from regulation of flows, degradation of habitat, lower water quality, barriers to fish migration, presence of alien species, pressure from recreational fishers, outbreak of disease and loss of genetic integrity, as well as drought (MDBC 2004).

White Box-Yellow Box-Blakely’s Red Gum Grassy Woodland and derived native grassland was declared a critically endangered ecological community under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) on 17 May 2006.

Only 2345 ha of the associated community Yellow Box-Red Gum Grassy Woodland (or 9.3% of the total remaining in the ACT and surrounding region from commencement of European settlement) are protected in nature reserves. Some are also protected on rural leases. Although the ACT meets the Regional Forests Assessment target of 15% of its original extent within its own borders, the total for the region is only 8.5%. Future signifi cant impacts will need to be referred to the Australian Government under the Environment Protection and Biodiversity Conservation Act 1999.

Preservation of individual trees does not protect the ecological community since the understorey is lost. Preservation next door to suburbs with no protection from pets such as cats and dogs is also unlikely to be particularly successful.

The ability of native species to be maintained in a landscape depends on the quality, quantity and connectivity of its preferred habitat. Achievement of this target will ensure conservation of endangered species and communities through successful implementation of recovery plans, strategies and action plans, and mitigation of key threatening processes.

The target relates to the 2008 baseline of 17 endangered species, 14 vulnerable species and two endangered communities in the ACT. Progress over the long term would see species and communities gradually becoming more secure and being removed from the list. If species (or communities) are allocated three points for extinct, two for endangered and one for vulnerable, the 2008 ‘conservation listing’ score for the ACT is 50. The target is to reduce this to 40 by 2030.

Natural challenges

ACT Natural Resource Management Council program

NATURAL CHALLENGES

Meeting distinctive challenges to the recovery of threatened and endangered species and ecological communities

Natural challenges projects are addressing nature conservation issues and threats from pest plants and animals by:

• rehabilitating subalpine peat bogs
• monitoring urban bushfire interfaces
• improving feral pig management in conservation areas
• improving kangaroo management in lowland grasslands and woodlands
• delivering environmental flows to large biota
• measuring and monitoring urban ecological function
• breeding and releasing corroboree frogs and
• monitoring and researching ACT frogs and Macquarie perch.

Parks Conservation and Land, CSIRO Sustainable Ecosystems

Kangaroos in Mt Majura woodlands.

Photo Sarah Ryan

Macquarie perch – native to the ACT and an endangered species.

Photo Environment ACT

 

Urban biodiversity

Canberra residents appreciate open space and easy access to reserves for relaxation and exercise. The green places in the urban area (between suburbs, along drainage lines, beside road corridors, across the hills) provide a rich and diverse urban ‘nature reserve’ of open woodland and grasslands in which a key element is interconnectedness. They are a valued ecological resource that include refuge for some endangered species and communities, as well as contributing to the community’s wellbeing and sense of place. The urban lakes (Burley Griffin, Tuggeranong and Ginninderra) also provide habitat for aquatic species and hold good populations of golden perch and Murray Cod as well as alien species.

This constructed landscape requires continued management and rejuvenation. It is managed under various management plans (e.g. the Canberra Nature Park Management Plan). The Tree Protection Act 2005 (ACT) is intended to protect exceptional trees (valued for heritage, landscape or scientific importance) and to provide protection for the urban forest where it is most needed.

Defining and setting a measurable target for urban biodiversity depends on more foundational work. It is likely to be a type of urban habitat-hectare measure that combines biodiversity area,
value and condition.