Vegetation Clearance: Position Statement by The Ecological Society of Australia

Summary

Vegetation clearance is a primary cause of past, current and predicted future losses of biodiversity for most groups of terrestrial animal and plant. Vegetation clearance is still continuing, often at alarming rates, and in most states there is no effective regulation of the extent and location of clearing activities.
The Ecological Society of Australia urges all levels of government to introduce controls on vegetation clearance in the states and territories that do not currently have adequate legislation, and to instigate programs for monitoring the effectiveness of these controls.

 Vegetation Clearance, Biodiversity and Ecosystem Processes

Vegetation clearance contributes to the process of habitat modification and fragmentation, which is recognised as the greatest threat to biological diversity in Australia (Biological Diversity Advisory Committee 1992). Local extinctions of vertebrate animals have typically occurred within decades of a region being developed for agriculture (Recher and Lim 1990) and more extinctions are likely to follow the current development of new areas in Australia 's north and west. Furthermore, in Victoria , where the current rates of clearing are relatively low, vegetation clearance is still regarded as a process threatening over 70% of animals and 50% of plants on the Flora and Fauna Guarantee list of threatened species (Department of Conservation & Environment 1992).
Many types of ecosystems are not represented in protected areas (eg. national parks and nature reserves) and continued unplanned vegetation clearance further diminishes the possibility of a representative system of protected areas ever being achieved. Furthermore "representation" of species or community types within reserves cannot be equated with their "conservation", since their continued occurrence within the reserves is typically dependent on ecological processes and the existence of habitat outside the reserves.
Vegetation cover plays a major "ecosystem services" role in maintaining the quality of soil, water and air. Vegetation clearing has an impact on the landscape with local, regional and global consequences. At the farm level, loss of vegetation cover is linked with soil erosion. Native vegetation provides shade, shelter and fodder for livestock and supports wildlife which contribute to the natural regulation of pest animals. At a regional scale clearing is known to have a major effect on hydrology and is linked to problems such as dryland salinity. A direct link between tree cover and the regional climate is less certain, but the possibility needs to be investigated. At a global scale, clearing contributes to the build-up of green-house gases in the atmosphere. According to Houghton et al. (1987), clearing in Australia caused the release of an estimated 28 million tonnes of carbon into the atmosphere in 1980.

Current Losses of Native Vegetation in Australia

By 1980 between 36 and 40% of Australia 's original estimated 280 million ha of forest and woodland had been significantly modified by clearing (Wells et al. 1984). The loss of vegetation has been concentrated in some ecosystems, particularly coastal areas and those favoured for agriculture. For example, over 80% of the Box-Ironbark woodland of eastern Australia has been cleared. Restoration of the affected ecosystems to a state approximating their original condition would be expensive and may not be possible. If achievable, it would certainly take hundreds of years.
The current rates of clearing are high, especially in Queensland and New South Wales , where there are no comprehensive controls. At least 500 000 ha are cleared annually in Queensland (Nadolny 1991). In southern Western Australia government authorities approved applications to clear 30,000-60,000 ha each year in the late 1980s (Schur 1990). In NSW an average of 430 000 ha per year were cleared in five separate years examined by the Australian Bureau of Statistics between 1972 and 1980 (Reed 1990). More recently, Sivertsen (1994) reported the removal of 67% of the remaining native vegetation in the area covered by the Goondiwindi 1:250 000 map sheet in the eight years preceding 1985. The clearing of 50.5 and 46% of remaining native vegetation was reported in the areas covered by the St George and Moree map sheets respectively over a similar time period. About 600,000 ha of native vegetation disappeared in these three mapped areas. In the Brisbane region Catterall & Kingston (1993) reported the destruction of 22% of remaining native vegetation between 1982 and 1990, and 34% of remaining native vegetation was cleared from the coastal south-east Queensland mainland between 1974 and 1989 (Sinclair et al. 1993).
There are also some areas, predominantly in semi-arid regions, where the cover of trees and woody shrubs has increased markedly since settlement by Europeans, perhaps to an undesirable extent. The ESA recognises that tree cover may need to be managed in such circumstances.

The Need for Control of Vegetation Clearance

There is an urgent need for controls on vegetation clearance because:

Current rates of clearing are high and the potential consequences are dramatic.

The environmental consequences of clearing (eg. dryland salinity and/or reduced water quality downstream, greenhouse effect, species extinctions) are long-term and their costs are often borne by the community as a whole whereas the individual that clears may benefit financially in the short-term (eg. by increased pasture production, cropping area or sales of timber). This leads to a tendency for individuals to over-clear and profit at the expense of the community at large (Nadolny 1991). While education of land managers is important to curtail reckless clearing and essential for fostering an understanding of the need for legislative change, education alone cannot limit the extent of clearing to an acceptable level.

Responsibility for control of vegetation clearing lies mainly with state and local governments. Of all the Australian states only Victoria and South Australia have comprehensive clearance controls. These two states have already lost so much vegetation cover that they face serious land degradation and water quality problems and loss of biodiversity. The ESA recommends that a proactive approach be taken so that clearance is restricted before such problems emerge.

We urge all levels of government to introduce or tighten controls on vegetation clearance so that the loss of terrestrial biodiversity and land and water degradation are stemmed. Controls on clearing could consist of a mixture of regulations to discourage clearing or otherwise limit its extent and location, and financial incentives to encourage retention and sound management of native vegetation. Typically, vegetation clearance should require an application to a controlling body. That controlling body will assess the conservation value of the site and make recommendations according to the best available information and ecological principles. Legislation needs to be enacted quickly to stop panic clearing. In regions with only a small percentage of original vegetation cover there must be an immediate end to clearance of native vegetation. In general, there needs to be broad policies targeted at vegetation, such as no "net loss". These policies must be coupled with comprehensive monitoring of changes in vegetation cover to assess their effectiveness.

References

Biological Diversity Advisory Committee (1992) A National Strategy for the Conservation of Australia 's Biological Diversity, Draft. May 1992, DASET, Canberra .

Catterall, C.P. and Kingston , M. (1993) Human populations, bushland distribution in south east Queensland and the implications for birds. In: Birds and their habitats: Status and Conservation in Queensland . Queensland Ornithological Society Inc., pp105-122.

Department of Conservation & Environment (1992) Flora and Fauna Guarantee Strategy: Conservation of Victoria 's Biodiversity. Draft prepared under the Flora and Fauna Guarantee Act 1988, September 1992.

Houghton, R.A., Boone, R.D., Fruci, J.R., Hobbie, J.E., Melillo, J.M., Palm , C.A. Peterson, B.J., Shaver, G.R. and Woodwell, G.M. (1987) The flux of carbon from terrestrial systems to the atmosphere in 1980 due to changes in landuse: geographic distribution of the global flux. Tellus 39B, 122-139.

Nadolny, C. (1991) The dilemma of rural tree clearing. Search 22, 43-46.

Recher, H. F. and Lim, L. (1990) A review of current ideas of the extinction, conservation and management of Australia 's terrestrial vertebrate fauna. Proc. Ecol. Soc. Aust. 16, 287-301.

Reed, P.C. (1990) An historical perspective on "Conserving What?" - The basis for nature conservation reserves in New South Wales 1967-1989. Aust. Zool. 26, 85-91.

Schur, B. (1990) W.A.'s biggest nature conservation problem: land clearing in the south west. Land & Water Research News 5, 6-9.

Sinclair, L.K., Jermyn, D., Preston , R.A. and Catterall, C.P. (1993) Status and change of remnant vegetation in south-east Queensland 1974-1989. Report to Nature Conservation Project, SEQ2001, Qld Dept. of Housing , Local Government & Planning. Qld Dept. of Primary Industries, Forest Service.

Sivertsen, D. (1994) The native vegetation crisis in the wheat belt of NSW. Search 25, 5-8.

Wells, K.F., Wood, N.H. and Laut, P. (1984) Loss of forests and woodlands in Australia : a summary by state, based on rural local government areas. CSIRO Instit. Biol. Sci. Tech. Mem. 84.