How to use this survey
Inventory and condition surveys can help people in the pastoral industry to plan for sustainable use of natural resources and the protection of those areas suffering from degradation or at risk of degradation.
The Western Australian part of the Nullarbor region survey was undertaken between 2005 and 2007 by PA Waddell, AK Gardner and P Hennig. The department published this survey in 2010 as Technical bulletin no. 97 An inventory and condition survey of the Western Australian part of the Nullarbor region.
The survey reports identify and describe the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. They also assess the impact of pastoralism and make land management recommendations, including recommended carrying capacities for each pastoral lease.
The department has surveyed and reported on 14 rangeland areas since 1972. Most of the rangeland pastoral leases have been surveyed, except for leases in the Southern Goldfields region and to the north-east of Wiluna-Meekatharra. The 15th rangeland survey — in the Southern Goldfields region, covering the area known as the Great Western Woodlands — is in progress and will be published in 2018.
Survey area and inventory summary
The Nullarbor region has unique, extensive, gently undulating stony plains of limestone karst that form the Bunda Plateau. As well as vast treeless plains through the region's centre, the Bunda Plateau is Australia’s largest karst and the world’s largest arid karst region (about 250 000 square kilometres).
An area of about 118 358 square kilometres was covered in the Nullarbor survey. The northern survey limits are defined by pastoral lease boundaries and the southern limits are bounded by the Southern Ocean. The western limits of the survey area are defined by the western-most Nullarbor pastoral lease boundaries and the eastern limit is defined by the Western Australia – South Australia border.
Pastoralism is the most extensive land use. Twenty pastoral leases fall wholly within the survey area and collectively occupy about 57 673 square kilometres (49% of the area). Areas set aside for nature conservation at the time of survey covered about 9526 square kilometres (8% of the area), consisting of the Eucla National Park, the Great Victoria Desert and the Nuytsland Nature Reserves, and some smaller parcels of land.
Eighteen soil groups are identified within the survey area. The most common soil group is calcareous shallow loams, occurring on all but coastal and subcoastal land systems. In comparison with other biogeographic regions in Western Australia, the flora of the Nullarbor region is not particularly diverse, with 426 vascular species recorded during the survey. Of these species, 383 are native. Eight of the 15 plant species on the Declared Rare and Priority Flora listing for the survey area were collected during the survey.
The survey report provides condition statements for the whole survey area and for each land system. Pasture and soil condition was assessed at more than 12 000 points throughout the survey area. Findings include:
- 66% of these points were in good rangeland condition
- 26% were in fair rangeland condition
- 8% were in poor rangeland condition.