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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Australian Terrestrial Biodiversity Assessment 2002
Paul Sattler and Colin Creighton
National Land and Water Resources Audit, 2002
ISBN 0 642 3713
Case Study
Murrumbidgee (Riverina 2) Second lowest stress class
Murrumbidgee River
Photo: NSW NPWS
The Murrumbidgee subregion is within the Western Riverina region in the south-west of NSW. The Murrumbidgee River dissects this subregion from Narrandera in the east to Balranald in the west, near the confluence of the Murray and Murrumbidgee Rivers.
A wide range of vegetation communities occurs in the subregion, some of which are unique to the Riverine Plain of NSW. The vegetation supports a diversity of species, including several endangered species. The Murrumbidgee subregion also contains extensive wetland areas including the Lowbidgee Floodplain wetland, the most extensive wetland in the Murrumbidgee catchment.
Land tenure is mainly a mix of freehold and leasehold. State Forest comprises less than 1% of land and is principally along the Murrumbidgee River. The subregion is a highly productive agricultural area, particularly the irrigation areas adjacent to the Murrumbidgee River. Sheep grazing on native pastures is the dominant land use (84% of the subregion). Approximately 6.8% is used for irrigated cultivation.
Condition and trend
About 25% of the land has been cleared of native vegetation, mostly on floodplains where the landscape is flat, soils are fertile and there is easy access to water. Compared to the whole bioregion, the Murrumbidgee subregion still retains areas of continuous native vegetation cover, as rainfall is lower and access to water more restricted. Condition is better to the west of the subregion, with native vegetation in the eastern portion more fragmented. Recent vegetation clearing information indicates that clearing rates are increasing to the west.
Threatening processes
Key threatening processes include:
- clearing and overgrazing;
- intensive agricultural production on lands adjacent to the Murrumbidgee River, leading to altered hydrological regimes, water logging, salinity, land degradation, vegetation decline and fragmentation;
- feral animals—one of the great historical impacts on the region's biodiversity was the massive proliferation of rabbits from the 1870's. This, combined with the droughts of 1883-85 and 1890-95, severely reduced the extent and condition of grass and herb species as well as those fauna species dependent on saltbush and grassland;
- fragmentation and degradation of woodland habitat, which threatens a number of species and ecosystems. Connectivity of woodland habitat is important for species that have a limited range and do not tolerate disturbance around their nest sites; and
- illegal egg collection and trapping for the bird trade, especially parrot species.
Management responses
The vegetation types that are reserved are not representative of the diversity of vegetation types or ecosystems that exist within the subregion, and are biased towards a few vegetation types. Two major planning process have the potential to assist reserve system design: Riverina Bioregional Conservation Planning; and Regional Vegetation Planning.
Species recovery plans are being developed for three bird species (Plains-wanderer, Superb Parrot, Regent Parrot) and one orchid (Caladenia arenaria).
Options to increase nature conservation on private land will be investigated within the Riverina Bioregion Conservation Planning project. These include:
- Voluntary Conservation Agreements (National Parks and Wildlife Service Act). These agreements are permanently binding on the land title and offer funding assistance and possible tax deductions as well as advice and support from NPWS staff.
- Wildlife Refuges (National Parks and Wildlife Service Act). A temporary voluntary mechanism. This also has some general legal requirements governing the management of the land while the refuge remains in place. It again offers the opportunity for advice and support from agency staff.
- Property Agreements (Native Vegetation Conservation Act). These agreements may be permanently or temporarily binding. Technical and management advice is provided and funding assistance may be provided depending on the length of the agreement.
The Conservation Trust Revolving Fund program will provide incentives for landholders to protect areas of high conservation value on private property compensates for the loss of productive land.
Limiting factors
The historically poor reservation status of both the Murrumbidgee and the Riverina is a consequence of several factors, namely the:
- historical lack of systematic State and regionwide conservation reserve planning;
- limited availability of Crown land for incorporation into the reserve system; and
- limited opportunity to purchase land due to high acquisition costs.
Key impediments to progress include:
- the overall lack of strategic coordination between government agencies, and between agencies and the private land owner communities. A good example is the Plantations Code of Practice and the Interim Regional Vegetation Schedule for the Riverina Highlands area that will allow for a further clearing of 40% of Yellow Box Woodland and 40% of White Box Woodland, without consent, as part of the government's drive to encourage farmers to establish plantations at minimum cost;
- available programs are not adequately resourced; and
- the plethora of target setting processes being undertaken by various agencies and groups for NSW landscapes. These diverse, and at times competitive, target exercises do not necessarily relate easily to the overall achievement of landscape conservation outcomes.
Future scenarios
Some significant gains in biodiversity conservation are expected to result from the Riverina Bioregional Conservation Planning Project. The current levels of degradation and loss of biodiversity will continue without considerable improvement in delivery of biodiversity conservation programs.
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