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 settlement native vegetation cover in Tasmania has decreased by some 1,768,600 ha from 4,878,000 ha to 3,109,400 ha (AUSLIG 1990). Changes in vegetation cover for particular vegetation types compiled from information supplied by the Tasmanian Department of Parks, Wildlife and Heritage are summarised in Table 8 below.
|Vegetation type||Pre-European (ha)||Present (ha)||Change (ha)|
|Native vegetation||4,878 0001||3,109,4001||1,768,600|
|Wet Eucalypt forest||1,272,7503||1,018,2003||254,550|
|Dry Eucalypt forest||2,853,2504||1,439,9004||1,413,350|
|Blackwood swamp forest||17,0405||1,0406||16,000|
1. Carnahan, AUSLIG. (1990).
2. Wells, P. (in press)]. The Rainforests of Tasmania.
3. Bosworth, P. and Wells, P. (pers comm)
4. Bosworth, P. (pers comm)
5. Inglis and Davey (1983) cited in Wells, P. (in press). Wet forests. In: Handbook of Vegetation Management.
6. Kirkpatrick, J.B. and Harwood, C.E. (1981). The conservation of Tasmanian wetland macrophyll species and communities. Unpublished Report to the Australian Heritage Commission.
7. Harris, S. (pers comm) including reclaimed saltbush around the Derwent estuary and drained saltmarshes converted to pasture at Ralphs Bay, Lauderdale, Pittwater, NW and E coast fragments and Moulting Lagoon.
8. Harris, S. (pers comm) almost half cleared - vast area in NE for British Tobacco in late 1960's, Clarke Island, Flinders Island, clearing of significant patches on N and E coasts for urban development, Blackmans Bay, and agricultural development along the East Coast.
9. Harris, S. (pers comm) including flooding under HEC schemes
10. Kirkpatrick, J.B. (1983). Treeless plant communities of the Tasmanian high country. Proc. Ecol. Soc. Aust. 12:61-77.
11. Kirkpatrick, J.B. and Glasby, J. (1981). Salt marshes in Tasmania: distribution, community composition and conservation. Geog. Dept. University of Tasmania. Occasional Paper No. 8.
12. Harris, S. (pers comm) Dept. of Parks, Wildlife and Heritage. Wildlife Division Internal Report.
Source: Tasmanian Department of Parks, Wildlife and Heritage cited in Kestel Research and VICDCE (1990, p.21)
Significant clearance of native vegetation, mainly for agricultural purposes, has occurred in the last two decades. Analysis of Landsat imagery from 1972 to 1980 has shown that at least 74 000 ha of native vegetation were converted to pasture. Of this total at least 69 500 ha were previously covered by dry eucalypt forest, the remaining being heath country. In addition, losses to pine plantations amounted to about 24 000 ha and hydroelectric impoundments covered 51 800 ha. These losses equate to a total of 2.3 per cent of the area of mainland Tasmania, a total area of about 150 000 ha at an average of about 19 000 ha per year (Kirkpatrick and Dickinson 1982, p.187).
Source: Kirkpatrick (1991, p.12)
Most of the conversion of forest to pasture occurred along the margins of already cleared land, or in remnant patches of native vegetation within already cleared land. Clearing was concentrated in areas readily accessible to the major woodchip export ports and was undertaken almost totally in dry eucalypt forests with grass, bracken or sclerophyll scrub understorey. The recent loss of habitat due to vegetation clearance or inundation has occurred mostly in east and northwest Tasmania (Kirkpatrick and Dickinson 1982).
In the period 1980 to 1988, 48 000 ha of vegetation were cleared or 6 000 ha per year. A breakdown into vegetation types is provided in Table 9 below.
The rate of clearance decreased by about 40 per cent between the periods 1972-80 and 1980-88. This decline could possibly reflect the reduced availability of natural vegetation and deep soils on relatively flat private land (Kirkpatrick 1991 p.11).
|Vegetation type||Per cent cleared per year (1980 base)||Area 1988 ('000 ha)|
|Inland E. tenuiramis dry forest||0.66||60|
|Inland grassy forest||0.65||175|
|Coastal grassy forest||0.42||192|
|E. sieberi dry forest||0.09||48|
|E. obliqua wet forest||0.08||154|
|E.obliqua tall forest||0.03||479|
Source: Adapted from Kirkpatrick (1991, p.13)