Erosion and rangeland condition in the West Kimberley

Page last updated: Wednesday, 18 July 2018 - 11:23am

The Department of Primary Industries and Regional Development and the Department of Planning, Lands and Heritage surveyed erosion and rangeland condition in the West Kimberley region in 1972. The survey defined the extent, location and severity of erosion and pasture degradation, and mapped land system areas. The survey report provides land managers, advisors and administrators with a baseline record of the condition of the area’s natural resources to assist with planning and implementing land management practices.

How to use this survey

Inventory and condition surveys assist people in the pastoral industry to plan sustainable use of existing natural resources and the protection of those areas suffering from degradation or at risk of degradation.

A survey of the West Kimberley region of Western Australia was undertaken in 1972 by A Kubicki, LC Short, DG Wilcox and AL Payne and was published in 1979 as Technical bulletin no. 42 'A report on erosion and range condition in the West Kimberley area of Western Australia'.

The survey report identifies and describes the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animal. It also assesses the impact of pastoralism and makes land management recommendations, including recommended carrying capacities for each pastoral lease.

Fourteen inventory and condition surveys have been published since 1972, and most of Western Australia’s rangeland pastoral leases have been surveyed, except for pastoral 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 being conducted in 2017.

Survey area and inventory summary

The area surveyed covers about 89 600 square kilometres (km²) in the catchments of the Fitzroy, Lennard, Meda and May rivers.

The survey found that the worst-affected pasture lands were:

  • frontage grass and black soil plain pastures closely associated with the major rivers
  • frontage grass and ribbon grass pastures of drainage floors, plains and valleys
  • white grass/bundle bundle pas­tures of valleys with basaltic red earth soils in the east and north-east of the survey area
  • short grass pastures of un­dulating interfluves and alluvial drainage floors in the central and eastern parts of the survey area.

Condition summary

The survey report provides condition statements for the whole survey area and for each land system. Findings include:

  • nearly 20% (17 500km²) of the survey area was in good rangeland condition; this country consisted mainly of poorly accessible land systems and systems supporting low quality spinifex pastures
  • nearly 51% (45 400km²) of the area was in fair rangeland condition
  • nearly 30% (26 700km²) of the area was in poor rangeland condition; pastures were degraded to poor or very poor condition and moderate and severe erosion was widespread
  • the worst areas of degradation and erosion were on the most valuable pasture lands.

The report recommends that about 6920km² of poor condition rangeland be removed from the area being grazed, within 3 years, to prevent irreversible degradation.

Contact information

Matthew Fletcher
+61 (0)8 9166 4019