Australian Natural Resources Atlas

Natural Resource Topics

Australian Terrestrial Biodiversity Assessment 2002

Paul Sattler and Colin Creighton
National Land and Water Resources Audit, 2002
ISBN 0 642 3713

Case Study

Victorian Volcanic Plain 1 Highest stress class

A high quality remnant of Basalt Plains Grassland. This threatened ecosystem once covered over 75% of the subregion - approximately 1% remains and much of this is degraded.

A high quality remnant of Basalt Plains Grassland. This threatened ecosystem once covered over 75% of the subregion - approximately 1% remains and much of this is degraded.

Photo: V. Craigie

The Victorian Volcanic Plain is an area of flat to undulating plains stretching from north of Melbourne to Portland in Western Victoria. The region is characterised by fertile volcanic derived soils that was covered with open grasslands and grassy woodlands, interspersed with stony rises and numerous volcanic eruption points, large shallow lakes and wetlands. Few major rivers cross the plain.

The Victorian Volcanic Plain was one of the first areas settled for agriculture in Victoria. Originally the Volcanic Plain was developed as pasture. Cropping and plantation forestry are now major land uses. There is very little public land.

Condition and trend

Greater than 95% of all native vegetation has been cleared. Seventy-eight Ecological Vegetation Classes and floristic communities were mapped in the bioregion. Fifteen percent of these are probably extinct and 78% threatened. Plains Grassland and Grassy Woodlands once covered three quarters of the subregion. Today only approximately 1% remains, and much of this is degraded.

Sixty-five taxa are listed as nationally threatened and 173 as threatened in Victoria (15 mammals, 61 birds, 4 reptiles, 1 frog, 8 fish, 2 invertebrates and 93 plants). Twelve are listed as extinct. Twenty taxa were assessed as having declining populations, 18 as static and 6 as increasing.

Nine lakes are included in the Ramsar convention of wetlands of international importance. An additional twenty-six wetlands are listed in the Directory of Important Wetlands in Australia. Over 75% of shallow freshwater wetlands have been modified or destroyed and while most of the deeper permanent freshwater wetlands remain, their margins are often highly degraded. Waterways throughout the region are in poor health, with the majority of stream lengths being rated as in poor or very poor condition.

Threatening processes

The extreme depletion and relict nature of native vegetation and habitats including wetlands and the small size of the majority of remnants is the major threat to conservation of biodiversity. The impacts of severe fragmentation and lack of remaining habitat on vegetation communities and plant and animal populations are yet to be fully realised.

Major threatening processes include:

Management responses

Nature conservation reserves occupy approximately 1.3% of the Victorian Volcanic Plain. Approximately 40% of ecological vegetation classes are represented in parks and reserves. Land acquisition through the National Reserve System Program has increased the reservation level of Grassland and Plains Grassy Woodland. A comprehensive investigation of all known unreserved high priority vegetation remnants has been carried out and identifies priorities for further protection and reserve acquisition.

Biodiversity conservation will rely heavily on management on private land and the network of road and rail reserves and other public land. Threatened species recovery actions have been systematically documented at a landscape scale for species identified as high priority in the Victorian Volcanic Plain as part of the bioregional Action Plan. An action statement under the Flora and Fauna Guarantee Act 1988 has been prepared for the Western (Basalt) Plains Grassland Community, which was dominant across much of the subregion and is now extremely depleted. A process for prioritisation of protection, enhancement and restoration of native vegetation will be implemented through the Regional Native Vegetation Management Plans when these are finalised. Recovery actions are an immediate priority given the widespread extent of threatening processes, the extreme depletion of native vegetation and the vulnerability due to small size and isolation or habitat remnants and the populations they contain.

Integrated natural resource management activities are of great importance in the subregion to maintain basic ecosystem function and services and the biodiversity that is essential for and dependant on these processes. These activities are primarily coordinated through the strategies and associated plans of Regional Catchment Management Authorities (Glenelg-Hopkins and Corangamite) or the Port Phillip Catchment and Land Protection Board.

Relatively large areas of forest occur in the southwest of the region and these are widely used for resources, conservation and recreation. The management of these areas is under a Regional Forest Agreement that includes an assessment of forestry management and its impact on threatened species and communities.

Innovative projects with a biodiversity focus in the Victorian Volcanic Plains include a project to assess the potential impacts of raised bed cropping on biodiversity. This project will facilitate identification of areas where land use change may be detrimental to biodiversity. A second project is developing a biodiversity module for environmental management systems that integrate biodiversity management objectives into farm grazing practices.

The voluntary "Land for Wildlife" and conservation covenant programs have resulted in significant conservation gains. Fencing incentive schemes are targeted for biodiversity protection outcomes.

Other opportunities for improved natural resource management include incorporation of biodiversity conservation objectives into Local Planning Schemes, wider use of overlays and local policies to highlight and protect significant biodiversity values, and full implementation of local government roadside conservation plans.

Limiting factors

Opportunities for improving the occurrence of many vegetation types within the conservation reserve system are constrained by the limited areas of these communities remaining and hence the options available for either reservation of public land or purchase of private land. The generally high land prices across the Victorian Volcanic Plain, due to its suitability for agriculture or urban development, further limit opportunities for consolidating the reserve system.

Community capacity to undertake recovery actions is variable across the bioregion. It may be particularly limited where declining commodity values have reduced the profitability of dominant farming practices and alternatives have yet to be found. Improved stewardship schemes and further public investment would provide opportunities to increase the actions undertaken and strengthen the viability of some farming businesses. Increased access to information, technical training and key resources would greatly add value to these efforts.

Figure 10.15: The proportional difference among strategies of resources required and resources currently available to ensure adequate biodiversity conservation.

Figure 10.15: The proportional difference among strategies of resources required and resources currently available to ensure adequate biodiversity conservation.

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