Australian Natural Resources Atlas

Natural Resource Topics

Australian Native Vegetation Assessment 2001

Maria Cofinas, Colin Creighton
National Land and Water Resources Audit, 2001
ISBN 0 642 37128 8

Cleared native vegetation: what and where?

Ringbarked trees, Womblebank, Qld

Ringbarked trees, Womblebank, Qld

Photo: Murray Fagg

What are the key types of native vegetation lost?

Key findings

Table 12 details the clearing of native vegetation by major vegetation groups across Australia. At a continental scale, approximately 13% of the total land has been cleared. This clearing has been concentrated (see Figure 11), reflecting settlement patterns and areas most capable of supporting development. Clearing has occurred predominantly for human settlement and agriculture in the higher rainfall regions and where there are more fertile soils, generally excluding the arid interior and tropical far north. Major vegetation groups that have been cleared since European settlement are shown in Figure 19.

The condition of the vegetation varies even if the broad native vegetation fabric is still intact, condition may still be declining (discussed separately in later sections on vegetation condition).

Eucalypt open forests: about 30% of pre-European extent cleared, accounting for 10% of total clearing:

Eucalypt open forests were extensively cleared in the latter half of the 19th century for:

Continued loss of these communities would have occurred if substantial areas had not been set aside in Crown reserves for timber production and later for nature conservation. The reservations for state forests are a good example of the foresight of resource managers at the time. Other examples are the various reservations of river foreshores, tidal waters and mangrove communities in many States and Territories as crown land administration systems developed. The Bulletin of the late 1890s through to the early 1900s includes much discussion about the reservation of lands for forestry and public uses, including opposition to the concept of state forests by various agricultural interests.

Eucalypt woodlands and eucalypt open woodlands: approximately 31% and 25% of pre-European extent cleared, accounting for 32% and 13% of total clearing respectively:

Eucalypt woodlands and eucalypt open woodlands are an important component of cereal cropping and pastoral zones. Cleared areas are very extensive, resulting in the loss of the broad fabric of the landscape from a vegetation perspective. Within the remnants, the shrubby understorey has often been removed mechanically, by frequent fire, or by the invasion of exotic species or overgrazing of native tussock grasses (annuals often replacing perennials). Eucalypt open woodlands areas mapped as native vegetation may be highly modified.

Inland acacia forests and woodlands: approximately 15% of pre-European extent cleared, accounting for 10% of total clearing:

Agricultural and pastoral development have led to major changes in extent and condition of these landscapes, expecially in brigalow (Acacia harpophylla) and mulga (A. aneura) communities. Extensive areas of brigalow, that once extended from Collinsville in Queensland to Narrabri in New South Wales, have been cleared. Approximately 4 million hectares of this brigalow was cleared as part of government land development schemes (Webb 1984). Few substantial areas remain in the southern Brigalow Belt. The government also encouraged clearing of mulga country. The expansion of grazing across the mulga lands occurred from the 1850s to the 1890s.

Mallee woodlands and shrublands: approximately 35% of pre-European extent cleared, accounting for 14% of total clearing:

As with the Brigalow Belt, encouragement for clearing was provided by government in the temperate mallee woodlands areas. Clearing was encouraged for cereal cropping and pastoralism and was often a condition of leases.

Rainforest communities: most lowland occurrences cleared, approximately 30% of pre-European extent cleared, accounting for 1% of total clearing:

The broad range of rainforest and vine thicket communities across Australia found within this major vegetation group masks the level of regional depletion of some rainforest and vine thicket types.

In the coastal lowlands, floodplains and more undulating sections of the coastal ranges of eastern Australia much of the rainforest communities have been cleared. These were among the earlier native vegetation communities to be exploited for timber (using coastal rivers to gain access and transport timber out for export). Notable examples of subtropical rainforests being cleared for timber, dairy or agriculture (e.g. sugar cane or tobacco) are:

In the Brigalow Belt of Queensland and north-western New South Wales, extensive areas of vine thickets, notably the softwood scrubs, were substantially cleared for agriculture or grazing as part of Brigalow land development.

Heath communities: approximately 45% of pre-European extent cleared, accounting for 2% of total clearing:

Heaths have been heavily impacted by clearing for sand mining, agriculture, grazing or development mainly in southern coastal areas. Mallee communities, which occur in association with some heath communities, have similarly had extensive areas cleared, mainly for pastoral development in Victoria and South Australia.

Tussock grasslands: approximately 10% of pre-European extent cleared, accounting for 6% of total clearing:

Many of the tussock grasslands (Mitchell grass) of eastern Australia have been either substantially cleared or heavily modified from grazing. The mapping of this type in the National Vegetation Information System reflects where there is good information on native grasslands. There are known to be many other areas either not mapped or subject to change through grazing and introduced species such as buffel grass and other introduced pasture grasses. The Audit's rangelands report (NLWRA 2001d) discusses pasture management and condition in further detail.

Figure 19: Cleared major vegetation groups.
Table 12. Area (km²) of major vegetation groups cleared* in Australia and the percentage cleared as a proportion of the total area of clearing in Australia.
Major vegetation group Area (km²) Percent cleared across Australia as total of clearing
Rainforest and vine thickets 13,262 1.4
Eucalypt tall open forests 14,688 1.5
Eucalypt open forests 100,484 10.3
Eucalypt low open forests 2,144 0.2
Eucalypt woodlands 318,598 32.5
Acacia forests and woodlands 96,933 9.9
Callitris forests and woodlands 3,239 0.3
Casuarina forests and woodlands 12,508 1.3
Melaleuca forests and woodlands 2,988 0.3
Other forests and woodlands 5,944 0.6
Eucalypt open woodlands 129,633 13.2
Tropical eucalypt woodlands/grasslands 2,206 0.2
Acacia open woodlands 3,238 0.3
Mallee woodlands and shrublands 132,979 13.6
Low closed forests and closed shrublands 7,115 0.7
Acacia shrublands 16,458 1.7
Other shrublands 16,877 1.7
Heath 21,297 2.2
Tussock grasslands 60,214 6.1
Hummock grasslands 858 0.1
Other grasslands, herblands, sedgelands and rushlands 1,981 0.2
Chenopod shrubs, samphire shrubs and forblands 10,995 1.1
Mangroves, tidal mudflats, samphires and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes 5,064 0.5
Note: * Clearing does not include grazing, thinning or other activities. In particular; parts of the rangelands may be heavily disturbed.

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.

Logging south of Coffs Harbour, NSW

Logging south of Coffs Harbour, NSW

Photo: Maria Cofinas

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.

Which bioregions have lost most native vegetation?

Key findings

Australia has 85 designated bioregions (Environment Australia 2000). The extensive clearing of native vegetation has been concentrated in comparatively few regions. Five bioregions (some of the key agricultural zones of south-eastern and south-west Australia) (Table 13 and Figure 20) have less than 30% of native vegetation remaining:

Sand mining damage, Stradbroke Island, Qld

Sand mining damage, Stradbroke Island, Qld

Photo: Murray Fagg

Twenty-two bioregions have between 30% and 70% of native vegetation remaining:

Fifty-eight bioregions have greater than 70% of native vegetation remaining.

Detailed information on each major vegetation group cleared and the percentage of pre-European vegetation remaining for the five bioregions with less than 30% remaining native vegetation is presented in Table 14. This break-up is extremely valuable in assessing the status of each vegetation group within a region, in particular for regions where the total clearing may not be high but particular vegetation groups within the region are being targeted for clearing.

Table 13: Summary figures of clearing and remaining native vegetation for IBRA bioregions with less than 30% of native vegetation remaining.
  Victorian Midlands Naracoorte Coastal Plain South East Coastal Plain Avon Wheatbelt Victorian Volcanic Plain
Area cleared (ha) 2,704,748 1,948,364 1,339,960 8,132,108 1,998,844
Total area of bioregion (ha) 3,782,384 2,541,888 1,697,036 9,517,188 2,162,192
Percent cleared native vegetation 71.5 76.7 79.0 85.4 92.4
Percent remaining native vegetation 28.5 23.3 21.0 14.6 7.6

Figure 20: Percentage native vegetation by IBRA bioregion.

Figure 20: Percentage native vegetation by IBRA bioregion.

Figure 21: Percentage native vegetation by IBRA subregion.

Figure 21: Percentage native vegetation by IBRA subregion.
Table 14: Area (ha) of major vegetation groups and clearing for IBRA bioregions with <30% of native vegetation remaining.
Major vegetation groups
  Rainforest and vine thickets Eucalypt tall open forests Eucalypt open forests Eucalyptlow open forests Eucalypt woodlands Acacia forests and woodlands Callitris forests and woodlands Casuarina forests and woodlands Melaleuca forests and woodlands Other forests and woodlands Eucalypt open woodlands Mallee woodlands and shrublands Low closed forests and closed shrublands Acacia shrublands Other shrublands Heath Tussock grasslands Other grasslands, herbland, etc Chenopod shrubs, samphires, etc Mangrove group
Naracoorte Coastal Plain
present vegetation - 12 46,652 1,308 146,048 36 - 328 4,552 104 5,092 161,060 16,644 12,724 76,764 45,388 7,760 26,068 19,496 23,488
cleared vegetation - 0 229,888 40 528,040 0 - 0 9,320 1,712 49,424 521,712 10,740 243,268 52,192 444 242,620 7,552 41,160 8,692
pre-European veg. - 12 276,540 1,348 674,088 36 - 328 13,872 1,816 54,516 682,772 27,384 255,992 128,956 45,832 250,380 33,620 60,656 32,180
percent remaining - 100 16.87 97.03 21.67 100 - 100 32.81 5.73 9.34 23.59 60.78 4.97 59.53 99.03 3.10 77.54 32.14 72.99
Victorian Volcanic Plain
present vegetation - 656 34,392 40 49,616 180 - - 4 708 1,020 1,932 4,484 0 852 36 4,512 872 9,320 54,724
cleared vegetation - 12,740 31,368 112 759,796 1,316 - - 72 11,260 266,260 964 34,808 16 63,208 52 770,592 44,988 920 364
pre-European veg. - 13,396 65,760 152 809,412 1,496 - - 76 11,968 267,280 2,896 39,292 16 64,060 88 775,104 45,860 10,240 55,088
percent remaining - 4.90 52.30 26.32 6.13 12.03 - - 5.26 5.92 0.38 66.71 11.41 0 1.33 40.91 0.58 1.90 91.02 99.34
South East Coastal Plain
present vegetation 8 14,864 109,444 928 65,112 1,008 - - 548 35,464 1,056 - 19,736 928 9,336 9,248 1,028 22,156 37,200 29,012
cleared vegetation 120 46,164 328,952 316 635,084 17,880 - - 4,004 14,476 3,292 - 147,780 2,004 11,920 2,356 48,040 51,460 2,396 480
pre-European veg. 128 61,028 438,396 1,244 700,196 18,888 - - 4,552 49,940 4,348 - 167,516 2,932 21,256 11,604 49,068 73,616 39,596 29,492
percent remaining 6.25 24.36 24.96 74.60 9.30 5.34 - - 12.04 71.01 24.29 - 11.78 31.65 43.92 79.70 2.10 30.10 93.95 98.37
Avon Wheatbelt
present vegetation - 4 720 - 525,408 4 - 6,836 532 952 36,588 87,024 52,176 271,356 216,184 31,916 - - 103,800 51,580
cleared vegetation - 36 1,696 - 92 152 - 17,668 2,012 4,532 4,824,552 813,108 339,224 488,420 848,204 387,540 - - 235,996 168,876
pre-European veg. - 40 2,416 - 525,500 156 - 24,504 2,544 5,484 4,861,140 900,132 391,400 759,776 1,064,388 419,456 - - 339,796 220,456
Percent remaining - 10.00 29.80 - 99.98 2.56 - 27.90 20.91 17.36 0.75 9.67 13.33 35.72 20.31 7.61 - - 30.55 23.40
Victorian Midlands
present vegetation - 69,756 122,372 9,912 691,112 1,420 724 - - 300 33,892 28,056 8,180 - 23,972 14,132 1,648 17,348 19,712 35,100
cleared vegetation - 90,048 83,044 9,520 1,836,544 7,188 2,000 - - 3,072 552,060 23,432 5,888 - 9,168 440 68,144 14,128 8 64
pre-European veg. - 159,804 205,416 19,432 2,527,656 8,608 2,724 - - 3,372 585,952 51,488 14,068 - 33,140 14,572 69,792 31,476 19,720 35,164
percent remaining - 43.65 59.57 51.01 27.34 16.50 26.58 - - 8.90 5.78 54.49 58.15 - 72.34 96.98 2.36 55.12 99.96 99.82
Table 15: Area (ha) of major vegetation groups and clearing for the Tasmanian Northern Slopes IBRA bioregion with 64% of native vegetation remaining.
  Rainforest and vine thickets Eucalypt tall open forests Eucalypt open forests Eucalypt low open forests Eucalypt woodlands Acacia forests and woodlands Other forests and woodlands Eucalypt open woodlands Low closed forests and closed shrublands Other shrublands Heath Tussock grasslands Other grasslands, herbland, etc Mangrove group
present vegetation 47,824 76,884 250,376 - 5,636 124 168 104 3,564 496 420 344 4,448 6,228
cleared vegetation 6,572 98,392 27,460 332 48,060 6,880 - - 39,112 - - - - -
pre-European vegetation 54,396 175,276 277,836 332 53,696 7,004 168 104 42,676 496 420 344 4,448 6,228
percent remaining 88 44 90 - 10 2 100 100 8 100 100 100 100 100
Note: - Indicates that this major vegetation group does not exist in a particular jurisdiction or that the scale and type of mapping compiled has not captured this major vegetation group.
Dust storm, ploughed mallee, Mildura-Renmark Road, Vic

Dust storm, ploughed mallee, Mildura-Renmark Road, Vic

Photo: Murray Fagg

An example of a bioregion with a much higher total percentage of native vegetation remaining is the Tasmanian Northern Slopes bioregion with 64% of native vegetation remaining. Information on remaining native vegetation extent, clearing and percentage relative to pre-European extent is presented in Table 15. Within this bioregion a number of major vegetation groups have either been cleared or have less than 30% of their pre-European extent remaining. They include eucalypt low open forests, eucalypt woodlands, acacia forests and woodlands and low closed forests and closed shrublands.

Many bioregions cover very large areas. It is useful to analyse the data to assess clearing levels in absolute terms (e.g. from Table 16, in 25 of the 85 bioregions native vegetation clearing exceeds 1 million hectares; these bioregions contain 91 million hectares of cleared land-92% of the total area of native vegetation cleared area in Australia; these bioregions occur across south-western Western Australia, southern South Australia, most of Victoria and New South Wales and central and southern Queensland).

Only an additional three bioregions have 800,000 - 1,000,000 ha of clearing. These are the Desert Uplands bioregion in Queensland, the Cobar Peneplain in New South Wales and the Swan Coastal Plain bioregion in Western Australia. The remaining 14 bioregions have 100 000 - 800,000 ha of native vegetation removed.

Table 16: Bioregions with greater than 800,000 ha of native vegetation cleared.
IBRA bioregion Cleared native vegetation (ha) Total area of region (ha) Percent cleared native vegetation Percent remaining native vegetation
Desert Uplands 811,564 7,032,020 11.5 88.5
Cobar Peneplain 820,516 7,350,240 11.2 88.8
Swan Coastal Plain 915,752 1,512,400 60.5 39.5
Sydney Basin 1,142,868 3,632,932 31.5 68.5
Mitchell Grass Downs 1,167,240 33,513,668 3.5 96.5
Flinders Lofty Block 1,300,556 7,126,092 18.3 81.7
South East Coastal Plain 1,339,960 1,697,036 79.0 21.0
Esperance Plains 1,402,020 2,906,644 48.2 51.8
Nandewar 1,748,584 2,698,724 64.8 35.2
New England Tableland 1,774,852 3,004,080 59.1 40.9
Geraldton Sandplains 1,921,976 3,966,988 48.4 51.6
Naracoorte Coastal Plain 1,948,364 2,541,888 76.7 23.3
Jarrah forest 1,959,380 4,507,968 43.5 56.5
Victorian Volcanic Plain 1,998,844 2,162,192 92.4 7.6
New South Wales North Coast 2,220,440 5,925,384 37.5 62.5
Victorian Midlands 2,704,748 3,782,384 71.5 28.5
Mulga Lands 3,307,320 25,299,496 13.1 86.9
South Eastern Queensland 3,376,096 5,943,728 56.8 43.2
Mallee 3,389,464 7,394,820 45.8 54.2
Darling Riverine Plains 3,428,472 10,652,152 32.2 67.8
South Eastern Highlands 3,697,800 8,743,444 42.3 57.7
Eyre Yorke Block 3,954,300 6,078,720 65.1 34.9
Riverina 4,580,904 9,589,472 47.8 52.2
New South Wales South Western Slopes 5,715,272 8,673,896 65.9 34.1
Brigalow Belt North 6,430,308 13,552,556 47.4 52.6
Murray Darling Depression 7,450,212 19,749,136 37.7 62.3
Avon Wheatbelt 8,132,108 9,517,188 85.4 14.6
Brigalow Belt South 14,948,992 26,926,740 55.5 44.5

Bioregions contain distinctive geomorphic units that closely align with land capability and development potential, termed subregions. The subregions mentioned previously developed as part of the Audit's Landscape Health initiative (NLWRA 2001c) provide a scale of analysis more appropriate to regional vegetation management planning.

This information with detailed vegetation types within bioregions and subregions is available on the Australian Natural Resources Atlas and provides the level of detail likely to be of value to regional groups as they plan for vegetation management and biodiversity conservation.

Applications

At the bioregion scale, the analysis provides an overview of the status of bioregions in terms of their native vegetation cover (a broad surrogate for biodiversity condition). At the subregion scale, the analysis provides information relevant to vegetation management planning, identifying key land types where management activities such as rehabilitation and protection for biodiversity conservation may be a priority.

Limitations

Bioregions cover large areas and are often bisected by administrative boundaries (e.g. local and State/Territory government boundaries or State/Territory land administration boundaries). Patterns of vegetation clearing are often influenced by these management factors. Therefore, the bioregion analysis is limited as an absolute indicator of bioregion condition.

The analysis is also limited by the quality of the present vegetation information compiled into the National Vegetation Information System and in development of the major vegetation groups. The limitations and guidelines provide information on the present vegetation products. In particular, recent clearing in some areas of Tasmania, New South Wales and Queensland are not mapped.

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