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

Present (2001-2004) Vegetation in Australia: 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

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

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:

Major Vegetation Groups Changes and Reservation (Word - 4780 KB)

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: 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.