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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.
Biodiversity and Vegetation - Western Australia
Western Australia
Proportion of native vegetation remaining in Western Australia
In Western Australia, 7% or 18.3 million hectares of native vegetation has been cleared. This has been almost completely concentrated in the agricultural zone of the south west, where a high proportion of the remaining native vegetation consists of small remnant patches of vegetation outside state forest, protected areas or crown land.
Major vegetation groups most affected by clearing are eucalypt open woodlands, mallee woodland and shrubland, heath, other shrublands, chenopod shrublands, acacia shrublands and eucalypt open forests.
Significant areas of native vegetation remain uncleared in the deserts of the arid interior, the Pilbara region and the tropical north such as the Kimberley region. Large areas have been disturbed by grazing of cattle, sheep and feral animals.
The Audit assessment of landscape health provides a summary on a subregional basis of the landscape stresses in Western Australia including clearing, grazing, feral animals and weeds (NLWRA 2001c).
| Major Vegetation Group | Pre-European Area (km2) | Circa 1997 Area (km2) | % remaining relative to pre-European area |
|---|---|---|---|
| Rainforest and vine thickets | 18 | 16 | 90 |
| Eucalyptus tall open forests | 2,757 | 2,343 | 85 |
| Eucalyptus open forest | 28,536 | 20,321 | 71 |
| Eucalyptus low open forest | 3,277 | 1,506 | 46 |
| Eucalyptus woodlands | 88,639 | 88,430 | 100 |
| Acacia forest and woodlands | 402,519 | 402,223 | 100 |
| Callitris forest and woodlands | 23 | 0 | 0 |
| Casuarina forest and woodlands | 3,348 | 3,139 | 94 |
| Melaleuca forest and woodlands | 1,596 | 1,189 | 75 |
| Other forests and woodlands | 5,190 | 2,977 | 57 |
| Eucalyptus open woodlands | 108,680 | 32,654 | 30 |
| Tropical Eucalyptus woodland/grasslands | 126,321 | 126,321 | 100 |
| Acacia open woodlands | 3,766 | 3,766 | 100 |
| Mallee woodlands and shrublands | 91,975 | 51,693 | 56 |
| Low closed forest and closed shrublands | 5,850 | 1,590 | 27 |
| Acacia shrublands | 247,652 | 238,771 | 96 |
| Other Shrublands | 53,382 | 42,246 | 79 |
| Heath | 38,806 | 17,822 | 46 |
| Tussock grasslands | 60,856 | 60,538 | 99 |
| Hummock grasslands | 999,222 | 998,696 | 100 |
| Other grasslands, herblands, sedgelands and rushlands | 8,110 | 7,855 | 97 |
| Chenopod shrub, samphire shrub and forblands | 192,402 | 189,665 | 99 |
| Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes | 52,207 | 48,111 | 92 |
Methods
This analysis is based on a comparison of the present extent of major vegetation groups (circa 1997) and pre-European mapping.
Applications
Analysis at the Australia-wide, State and Territory and regional scales provides information on which to base broad assessments of change in extent and type of vegetation. This is a key input to assessing:
- the representativeness or otherwise of Australia's nature conservation estate and for related interpretations (e.g. setting priorities for retention of native vegetation types);
- opportunities for catchment rehabilitation, whether the issue is catchment hydrology or dryland salinity control;
- the types of vegetation suitable for rehabilitation, restoration and/or revegetation activities in an area; and
- priorities for protection of biodiversity in landscapes under stress.
Limitations
Pre-European vegetation and present native vegetation for many States and Territories do not match in mapping method or scale. Development of pre-European vegetation maps in cleared areas of Australia is usually dependent upon coarse or generalised data on landforms and soils sometimes at 1:250 000 or even 1:1 000 000 scale. Reconstructing the natural complexity of vegetation patterns from such broad interpretations is difficult. Earlier vegetation mapping for areas now cleared may similarly be coarse in scale and/or generalised, with little data from systematic field sampling to support the derivation of mapping units and the allocation of individual patches of native vegetation to mapping units.
Pre-European data is more reliable where:
- impacts of European land use is minimal;
- there is good physical and floristic information (e.g. in Victoria) which can be used for detailed interpolation; and
- the scale of the pre-European mapping and method is similar to that of the current extent mapping (e.g. in Queensland, Victoria, Northern Territory and Western Australia).
Data variability is greatest in New South Wales, the Australian Capital Territory and South Australia, where the pre-European data does not meet the requirements of the National Vegetation Information System. In Tasmania the pre-European data is not finalised. In these States it is assumed that the present vegetation mapped is an approximate representation of the pre-European vegetation. The Australia wide pre-European major vegetation groups data set is an interim product.
What major vegetation groups have been cleared in Western Australia since European settlement?
| Major Vegetation Group | Cleared Area (km2) | % cleared across WA as total of clearing |
|---|---|---|
| Rainforest and vine thickets | 2 | 0 |
| Eucalyptus tall open forests | 414 | .2 |
| Eucalyptus open forest | 8,214 | 4.5 |
| Eucalyptus low open forest | 1,771 | 1 |
| Eucalyptus woodlands | 209 | .1 |
| Acacia forest and woodlands | 296 | .2 |
| Callitris forest and woodlands | 23 | 0 |
| Casuarina forest and woodlands | 209 | .1 |
| Melaleuca forest and woodlands | 406 | .2 |
| Other forests and woodlands | 2,213 | 1.2 |
| Eucalyptus open woodlands | 76,026 | 41.3 |
| Mallee woodlands and shrublands | 40,281 | 21.9 |
| Low closed forest and closed shrublands | 4,260 | 2.3 |
| Acacia shrublands | 8,880 | 4.8 |
| Other Shrublands | 11,137 | 6.1 |
| Heath | 20,984 | 11.4 |
| Tussock grasslands | 318 | .2 |
| Hummock grasslands | 527 | .3 |
| Other grasslands, herblands, sedgelands and rushlands | 256 | .1 |
| Chenopod shrub, samphire shrub and forblands | 2,737 | 1.5 |
| Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes | 4,095 | 2.2 |
Note: The clearing referred to in table 2 does not include grazing, thinning or other activities. In particular, parts of the rangelands may be heavily disturbed.
Map: Cleared Major Vegetation Groups (circa 1997) in Western Australia
Source:
Major vegetation groups V1.0 (1km), National Land and Water Resources Audit 2001. Data used are assumed to be correct from suppliers.
© Commonwealth of Australia 2001
The summary maps provide information on Australia's native vegetation collated within the National Vegetation Information System (NVIS) at July 2001 and with additional mapped information. The NVIS will be updated as vegetation mapping becomes available.
The map is a compilation of data collected at different scales by different organisations. Major Vegetation Groups were compiled by Environment Australia based on data collated by the Bureau of Rural Sciences and provided by Environment ACT, Department of Urban Services; NSW National Parks and Wildlife Service; NSW Royal Botanic Gardens; NSW State Forests; NT Department of Infrastructure, Planning and Environment; Queensland Herbarium, Environmental Protection Agency; SA Department for Environment and Heritage; Tasmanian Department of Primary Industries, Water and Environment; Flora Section, Department of Natural Resources and Environment; Agriculture Western Australia; Western Australia Department of Conservation and Land Management and Geoscience Australia, National Mapping Division.
Methods
This analysis is based on the present extent of native vegetation and data on the type and area of these groups cleared in Australia from the pre-European mapping. All summary findings are based on the data sets compiled for the National Vegetation Information System and development of the major vegetation groups.
Applications
This analysis at the Australia-wide, State and Territory and regional scales provides information on which to base assessment of change in land cover and type of vegetation, a key input to vegetation management activities. Loss of particular vegetation types across regions impacts on biodiversity values and landscape function and this analysis highlights those major vegetation groups.
At the regional scale, the National Vegetation Information System compilation provides an excellent basis for regional planning groups to understand the changes in vegetation extent that have occurred and set their regional priorities for vegetation management in the context of this information. The assessment of major vegetation groups across Australia provides a broader context.
Limitations
As detailed previously, issues of attributes, scale and currency of available mapping limits the precision of this analysis. The broad nature of the major vegetation groups masks the distinct vegetation types and regional clearing patterns that would emerge at a finer scale of analysis.
Link to cleared native vegetation information for Western Australia's bioregions
What sources of information were used?
View the guidelines for the interpretation of vegetation mapping products.
References
View the references used in the Australian Native Vegetation Assessment 2001.
Partnerships
Australian Native Vegetation Assessment 2001 was facilitated and coordinated by the National Land and Water Resources Audit and prepared in partnership with State, Territory and Commonwealth agencies:
Australian Capital Territory
Department of Urban Services
www.urbanservices.act.gov.au
New South Wales
www.dlwc.nsw.gov.au
NSW National Parks and Wildlife Service
www.npws.nsw.gov.au
NSW Botanic Gardens
www.rbgsyd.gov.au
Northern Territory
Department of Natural Resources, Environment and The Arts
www.nreta.nt.gov.au
Queensland
Environment Protection Agency
www.epa.qld.gov.au
South Australia
Planning SA
www.planning.sa.gov.au
Tasmania
Department of Primary Industries, Water and Environment
www.dpiwe.tas.gov.au
Victoria
Department of Sustainability and Environment
www.dse.vic.gov.au
Western Australia
Agriculture WA
www.agric.wa.gov.au
Commonwealth
Australian Greenhouse Office
www.greenhouse.gov.au
Department of Environment and Heritage
www.deh.gov.au
Further information
Exit to Agriculture WA
Exit to Department of Conservation and Land Management
View the Australian Native Vegetation Assessment 2001 report
The National Vegetation Information System Framework
View Landscape Health in Australia 2001 report
View the Australian Catchment, River and Estuary Assessment 2002
View the Australian Terrestrial Biodiversity Assessment 2002
View all Theme Reports from the National Land and Water Resources Audit
Link to dynamic mapping
Link to data available for download
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