Indicator: LD-01 The proportion and area of native vegetation and changes over time

Data

Prior to European settlement native vegetation covered most of Australia but now only 87% of the country is vegetated by native species. Most of the change has been from clearing of forests and woodlands, which originally covered 54% of the country and now covers 42% of the country. The following table provides a more detailed analysis of native vegetation remaining.

While grasslands, which were the most extensive original vegetation, have not been extensively modified, their condition is largely unknown.

Native forests and woodlands have born the brunt of the clearing. Since European settlement, about a quarter of Australia’s native forests and woodland has been cleared, mainly in what is now the intensive land use zone.

The following table shows the Native Vegetation Inventory Assessment (NVIS) of native vegetation by type prior to European settlement and as at 2001-2004.

Vegetation type Pre settlement NVIS 2005 Difference Percentage lost Percentage left Percentage of remaining vegetation in reserves
Rainforest and vine thickets 53,469 35,200 18269 34% 66% 54%
Eucalyptus Tall Open Forest 40,801 35,344 5457 13% 87% 34%
Eucalyptus Open Forest 394,280 272,121 122159 31% 69% 23%
Eucalyptus Low Open Forest 4,726 3,952 774 16% 84% 35%
Eucalyptus Woodland 1,362,263 892,920 469343 34% 66% 8%
Acacia Forest and Woodlands 495,059 408,632 86427 17% 83% 9%
Callitris Forest and Woodlands 40,278 32,296 7982 20% 80% 6%
Casuarina Forest and Woodland 166,303 149,262 17041 10% 90% 19%
Melaleuca Forest and Woodland 106,057 99,561 6496 6% 94% 10%
Other Forests and Woodlands 80,772 72,414 8358 10% 90% 10%
Eucalyptus Open Woodland 498,663 458,905 39758 8% 92% 6%
Tropical Eucalyptus woodlands/grasslands 115,503 112,481 3022 3% 97% 13%
Acacia Open Woodland 320,981 314,040 6941 2% 98% 8%
Mallee Woodland and Shrubland 387,230 271,529 115701 30% 70% 37%
Low Closed Forest and Tall Closed Shrublands 25,819 16,278 9541 37% 63% 31%
Mangroves 9,664 9,325 339 3% 97% 33%
Total forest and woodland 4,101,868 3,184,260 917,608 22% 78%
Acacia Shrubland 865,845 851,274 14571 2% 98% 10%
Other Shrublands 157,530 123,464 34066 22% 78% 19%
Chenopod Shrub, Samphire Shrub and Forbland 447,239 436,801 10,438 2% 98% 13%
Total shrublands 1,470,614 1,411,539 59,075 4% 96%
Heath 9,256 8,071 1,185 13% 87% 44%
Tussock Grassland 559,850 525,888 33,962 6% 94% 3%
Hummock Grassland 1,368,861 1,367,973 888 0% 100% 10%
Other Grassland, Herbland, Sedgeland and Rushland 67,977 64,810 3,167 5% 95% 17%
Total grassland 1,996,688 1,958,671 38,017 2% 98%
Total native vegetation 7,578,427 6,562,541 1,015,885 13% 87% 54%
Woody native veg cleared since settlement 4,092,204 3,174,935 917,269 22% 78%
Other veg cleared since settlement 3,476,558 3,378,281 98,277 3% 97%

The following figure shows these data graphically and also shows the proportion of each broad type of vegetation that is to some degree protected by virtue of being in reserves.

Areas of estimated pre-1750 and remaining (2001-04) vegetation in Australia (km2); area of remaining vegetation in reserves

Broad vegetation groups protected by reserves

The following maps show the change spatially. The whited out areas on the 2001-2004 map are the 13 per cent of Australia that has lost its native vegetation cover.

Estimated Pre-1750 Vegetation in Australia: Major Vegetation Groups

 Major Vegetation Groups

Present (2001-2004) Vegetation in Australia: Major Vegetation Groups

 Major Vegetation Groups

The following map shows IBRA regions by the percentage of total native vegetation remaining in each of them.

Percentage of vegetation remaining by IBRA regions

Percentage of vegetation remaining by IBRA regions

Source: Department of the Environment and Heritage 2005, National Vegetation Information System (NVIS) Stage 1, Version 3.0 Major Vegetation Groups, viewed N/A, http://www.deh.gov.au/erin/nvis/mvg/index.html

Source: Parks Australia 2006, National Reserve System Programme Priority Review (in prep.), DEH, Canberra.

The following map shows the number of vegetation groups with less than 30% remaining by IBRA regions.

Vegetation groups with 30% remaining by IBRA region

Vegetation groups with 30% remaining by IBRA region

Source: Department of the Environment and Heritage 2005, National Vegetation Information System (NVIS) Stage 1, Version 3.0 Major Vegetation Groups, viewed N/A, http://www.deh.gov.au/erin/nvis/mvg/index.html

Source: Parks Australia 2006, National Reserve System Programme Priority Review (in prep.), DEH, Canberra.

Source: Department of the Environment and Heritage 2006, National Vegetation Information System (NVIS) Stage 1, Version 3.0 Major Vegetation Groups, viewed 30 May 2006, http://www.deh.gov.au/erin/nvis/mvg/index.html

Source: Department of the Environment and Heritage 2006, National Reserve System Programme Priority Review 2006 (in prep.), DEH, Canberra.

For further information about the NVIS data see:

What the data mean

About 87% of Australia’s pre-European vegetation remains although clearing has not been uniform across major vegetation types. Many vegetation types have undergone significant changes since European arrival. ‘Low closed forest and tall closed shrublands’, for example, was uncommon and now is even more so, with only 63% remaining. About 66% of ‘rainforest and vine thickets’, remains. The rarest pre-European vegetation type was ‘Eucalyptus low open forest’ - about 84% remains. The most widespread pre-European vegetation type was hummock grasslands (covering about 18% of Australia) and most of it still remains although its condition and density of hummocks may have decreased due to grazing, weeds and other pressures. It is the densely settled coastal, temperate regions (originally mainly native forest and woodland), particularly on the eastern coast of the continent, that have lost most of their vegetation. Of the 13% of Australia’s original vegetation that has been lost since European settlement, most has been forests and woodlands. Almost a quarter of Australia’s native forests and woodland has been cleared, mainly in what is now the intensive land use zone.

However, the AGO data derived from remote sensing (see LD-03 Change in extent and proportion of woody vegetation, clearing and regrowth ) suggest that the situation may be even worse. According to these data, woody vegetation covers only 33% of the area estimated to be under woody native vegetation by NVIS, with only 26% of the continent’s original area of woody vegetation remaining.

Data Limitations

Methodologies for deriving quantitative assessments of the status of Australia’s native vegetation have been further developed since the native vegetation assessment undertaken for the National Land and Water Resources Audit in 2001, making comparisons between the NVIS estimates in 2005 and the Audit estimates in 2001 difficult.

The data does not indicate condition of the vegetation.

Methodologies for deriving quantitative assessments of the status of Australia’s native vegetation vary considerably.

The following table shows the NLWRA 2001 assessment of pre-European vegetation (by major vegetation type) and the more recent NVIS assessment of pre-European vegetation, with the Audit’s 2001 assessment of current vegetation and the NVIS 2005 assessment of current vegetation. The table shows the difficulty showing recent vegetation trends while methodologies for data collection and data interpretation continue to improve.

Comparative summary of NLWRA and NVIS data: pre-european, audit 2001 assessment and NVIS 2005 assessment
Pre-European
(NLWRA 2001 assessment)
Pre-European (NVIS 2005 assessment) NLWRA 2001 assessment
(Data date 1997)
NVIS 2005
(Data date 2001-2004 excl. NSW 1997-2004)
Forest and woodland (inc. some associated shrub, heath and grassland) 3 724 754 4 092 204 2 878 795 3 174 935
Other shrub and heath 1 397 105 1 480 675 1 331 481 1 419 610
Hummock grass 1 756 962 1 368 861 1 756 104 1 367 973
Tussock grass 589 212 559 850 528 998 525 888
Other grassland 100 504 67 977 98 523 64 810
Other (inc. bare ground, water bodies, mangroves, etc) 112 063 106 999
Cleared/modified Nil Nil 982 051

Source: Department of the Environment and Heritage 2005, National Vegetation Information System (NVIS) Stage 1, Version 3.0 Major Vegetation Groups, viewed N/A, http://www.deh.gov.au/erin/nvis/mvg/index.html

Source: National Land and Water Resources Audit 2001, Fragmentation of Australia's Native Vegetation: Applications, Australian Native Vegetation Assessment 2001, viewed 5 Jun 2006, http://audit.deh.gov.au/ANRA/vegetation/docs
/Native_vegetation/nat_veg_applications.cfm

Issues for which this is an indicator and why

Land — Land condition - Condition of terrestrial species and ecological communities 

To fully understand what is happening to species, habitats and ecological communities, we would need indicators that show long term changes in number of species present within each habitat and habitat type, changes in numbers and distribution within each species, both within each habitat and between different habitats, an understanding of how each different species interacts with each other species and of seasonal, climatic and anthropogenic changes in habitats. To understand these processes at a continental scale, we would need to have this information across all habitats comprising the continent’s ecosystems.

Even if these interactions were understood, we would need sufficient historical data or understanding of ecological processes to know whether a major fluctuation between species is indicative of a natural, ecologically beneficial process or is a symptom of anthropogenic degradation.

No indicators, which either individually or collectively have the capacity to do this, have been identified. In the absence of any way of assessing the overall condition of all aspects of Australia’s terrestrial biodiversity, and the ecosystem as a whole, considering the condition of a selection of key species, communities and habitats is probably the best we can do. Known declines in species, communities or habitats may be indicative of broader declines in species communities and habitats. In particular, the extent of native vegetation which provides habitat for species may serve as a surrogate indicator for the general condition of the species and ecological communities which maintain the overall condition of the land.

Vegetation provides habitat for life forms from all the kingdoms (other plants, animals, fungi, bacteria and viruses). While the mere presence (extent) of vegetation is not necessarily indicative of the condition of either the vegetation itself or of the other things that live there, the ecological communities which maintain the overall condition of the land are more likely to still be present where native vegetation is still present. Therefore, the extent of native vegetation may serve as a surrogate indicator for the general condition of the species, habitats and ecological communities which maintain the overall condition of the land.

Other indicators for this issue:

Land — Land condition - Land cover 

Extent of woody vegetation is a key indicator of the condition of land cover. Woody vegetation is predominantly perennial and generally contributes to deeper and more stable surface soil, deeper root systems and groundwater, better protection for surface water, a more life-friendly microclimate and a more secure habitat for other plants and animals. It therefore contributes to the capacity of the land to maintain its vegetative cover. Extent and change in extent of native vegetative cover is a direct indicator for this issue.

Other indicators for this issue:

Land — Direct pressure of human activities on the land - Land clearing 

While all the original vegetation cleared in Australia was, by definition, native vegetation, it is the perennial, deep-rooted, woody vegetation which is most significant in terms of providing habitats for other biota and protecting soil, micro-climate and water catchments. It is this type of vegetation that has seen the most significant reductions since the European invasion. Extent and change in vegetative cover show the extent of these reductions.

Other indicators for this issue:

Land — Direct pressure of human activities on the land - Species introduction and species change 

Change in extent of native species is also an indicator for change in extent of introduced (non-native) vegetation species. It may also be a surrogate indicator for distribution of naturalised fauna because naturalised fauna tend to be better adapted than native fauna to introduced vegetation.

Other indicators for this issue:

Biodiversity — Landscapes - Ecosystem diversity 

It is reasonable to assume that landscapes which retain their original vegetation cover with a minimum of modification, are likely to retain a higher proportion of their original biodiversity than landscapes that have been highly modified. The extent of native vegetation types compared with that existing prior to European settlement indicates the broad range of terrestrial habitats lost and remaining. The indicator can help identify vegetation types at risk from pressures such as increases in the extent of dryland salinity.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Land clearing 

Clearing of native vegetation removes the biodiversity living there both directly and by removing its habitat. Extent of land cleared of native vegetation gives a broad indication of the extent to which biodiversity has been affected.

Other indicators for this issue:

Biodiversity — Species, habitats and ecological communities - Conservation status of species and ecological communities 

Extent of native vegetation of various types remaining is indicative of the conservation status of those vegetation types.

Other indicators for this issue:

Inland Waters — Catchment scale influences — Land and vegetation condition - Vegetation 

Native vegetation is a determinant of the condition of inland waters. Vegetation helps keep the water table low and protects surface waters by shading them from direct sunlight and holding banks together. Native vegetation cleared is an indicator for this pressure on inland waters.

Other indicators for this issue:

Further Information

Extensive additional analysis of vegetation data are available in the source document and also in the NHT publication “Landscape Health in Australia”. The source of the data used in these reports in the National Vegetation Inventory System.

Changes to this document since December 2006

The first table reported against the indicator was missing its first column and included old data that had been updated prior to publication of SoE 2006. Some text had also been omitted from the section entitled "What the data mean", and some source information was also missing. These errors and omissions have been corrected.