An overview of recent native vegetation clearance in Australia and its implications for biodiversity
Biodiversity Series, Paper No. 6
Andreas Glanznig, Biodiversity Unit
Department of the Environment, Sport and Territories, June 1995
Since European colonisation in the 1830s of what is now Victoria, its forests and woodlands, grasslands and wetlands have been heavily impacted. In 1869 Victoria's forests and woodlands were estimated to extend over nearly 20 million ha, covering some 88 per cent of the State (Powell 1967). Studies have shown that in little more than 150 years since European settlement, over 65 per cent of Victoria's forest and woodland cover (some 12 million ha) has been cleared (Woodgate and Black 1988) (see Figure 9 and definitions below). In addition one third of the wetlands in Victoria have vanished, shrinking from an area of 725 600 to 531 200 hectares (VICDCE 1992). The impact on lowland native grasslands has been particularly severe (McDougall and Kirkpatrick 1994).
Notes: Victoria's forest and tree cover in 1869 as defined as: all woody vegetation with a height greater than 2 metres and a density (foliar cover) greater than 10 per cent. The map was derived from early survey records.
Victoria's forest and tree cover in 1987 as defined as: all woody vegetation with a height greater than 2 metres and a density (foliar cover) greater than 10 per cent. The map was derived from Landsat MSS satellite images.
Source: Woodgate and Black (1988, p.22, 23)
Victoria is one of the few States that comprehensively monitors the clearance of woody native vegetation and general habitat loss using Landsat MSS and TM satellite imagery and GIS technology.
Until recently the clearing of vegetation and habitat continued at a significant rate. For example, between 1972 and 1987 a total of 230 874 ha of mostly native forest was cleared; an average of about 15 392 ha per year gross or about 10 438 ha per year net (Woodgate and Black 1988).
The pattern of past clearing closely followed land types, which in turn reflected the capability of land for agriculture. Clearing was concentrated on the plains of northern and north-western Victoria and coastal Gippsland, extending into the highlands along the relatively flat and fertile valley floors.
The total area of forest for all classes of land by region for 1869, 1972 and 1987 is presented in Table 10 below.
|Region||1869||1972||1987||1987 Forest area
1869 Forest Area %
|Mildura||3 877 000||1 569 127||1 540 461||40|
|Horsham||2 214 000||589 514||529 996||24|
|Portland||1 654 000||312 646||299 352||18|
|Colac||500 000||195 129||192 206||38|
|Ballarat||625 000||153 394||148 881||24|
|Bendigo||1 932 000||308 333||299 112||15|
|Geelong||664 000||173 383||171 847||26|
|Benalla||984 000||162 727||160 843||16|
|Alexandra||1 039 000||514 489||514 837||50|
|North East||1 815 000||1 113 151||1 094 723||60|
|Dandenong||569 000||193 970||188 286||33|
|Yarram||586 000||193 739||185 798||32|
|Central Gippsland||1 361 000||931 705||933 863||69|
|Bairnsdale||1 170 000||872 880||867 679||4|
|Orbost||900 000||839 631||834 587||93|
|Melbourne||93 000||3 258||3 109||3|
|Total||19 983 000||8 127 076||7 965 580||av. 40|
Source: Woodgate and Black (1988, pp.16,20)
The Victorian Department of Conservation and Natural Resources has completed mapping the change to Victoria's tree cover for the period 1990 to 1993 and a full report with area statements is due to be published in mid-1995. In the interim, the indicative extent of clearance can be gauged from clearance permits which show that in the period between 1989-90 and 1992-93 some 15 136 ha of woody native vegetation were allowed to be cleared (GOV cited in NGGIC 1994, p. 129a).
Clearance of lowland native grasslands is still occurring at a significant rate. A recent study found that 44 per cent of the grassland sites in western Victoria recorded by John Stuwe in 1986 have been subsequently destroyed, severely degraded or are planned for destruction. About half of the remaining 'intact' sites have been reduced in size or degraded to some extent. The study concludes that without immediate action the decline of grasslands will continue (McDougall and Kirkpatrick 1994, pp.159-60).