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
As part of the processes of economic and social development that were encouraged by all governments following European settlement, large tracts of Australia's vegetation were cleared. Prior to the 1860s most clearing of vegetation, especially woodlands, was restricted to land around settlements. An increase in broadscale clearing occurred with the shift to wheat production, facilitated by the surplus of labour after the gold rush. During this century, agricultural expansion greatly increased, assisted by the technological advances made in heavy machinery and herbicides.
This trend increased significantly in the last 50 years. Contrary to the common wisdom that most clearance occurred last century and early this century, in the last 50 years as much land was cleared as in the 150 years before 1945 (AUSLIG 1990, p.6). Extensive clearing for agriculture occurred in the 1960s and 1970s and significant clearing is still taking place.
There is increasing concern about current patterns of native vegetation clearance. For example, the National Landcare Advisory Committee (NLAC) recommended to the Federal Minister for Primary Industries and Energy and the Federal Minister for the Environment, Sport and Territories that:
they communicate to [the] Agricultural and Resources Management Council of Australia and New Zealand and to [the] Australian and New Zealand Environment and Conservation Council, NLAC's concern that there remains in Australia evidence of excessive clearing of native vegetation (NLAC 1994).
The Committee has a broad representation. It includes the National Farmers' Federation, the Australian Local Government Association, the Australian Conservation Foundation, the Central Land Council, community representatives, the Commonwealth Department of Primary Industries and Energy, the Commonwealth Department of the Environment, Sport and Territories, and State Government officials representing the Agricultural and Resources Management Council of Australia and New Zealand and the Australian and New Zealand Environment and Conservation Council.
Increasingly the relationships between native vegetation clearance, habitat loss and fragmentation, and biodiversity decline are being recognised. Clearance of native vegetation reduces the continuous natural range of ecosystems as well as the diversity of habitats and ecological processes occurring within them. Clearance also affects species diversity. The disruption of an ecosystem into a number of isolated 'islands' can result in conditions adverse to the survival of species within the disrupted area. This includes opening up the area to a number of flow-on threats such as increased invasion by weeds and feral animals.
This paper seeks to increase understanding of the general ecological implications of native vegetation clearance, particularly as they relate to biodiversity decline, and to present an overview of recent native vegetation clearance both at the national and State/Territory levels. The analysis is subject to the following caveat: namely, that it is constrained by a lack of datasets which are comprehensive, precise and accurate at the State, Territory and regional levels, particularly for Queensland and New South Wales.
The value of native vegetation is being increasingly recognised. Native vegetation is important for a variety of ecological, economic and social reasons.
The ecological benefits of native vegetation result from its contribution to various vital yet usually undervalued ecosystem services. These include such services as:
- protecting water resources;
- forming and protecting soil;
- storage and cycling of nutrients;
- maintaining biodiversity;
- providing carbon sinks which absorb greenhouse gases;
- contributing to the maintenance of regional rainfall patterns; and
- producing oxygen.
Native vegetation also has a range of direct economic benefits which include:
- providing deep rooted vegetation which assists in maintaining water table levels and preventing salinity;
- providing shade and shelter to stock;
- providing windbreaks for crops;
- contributing to soil erosion control;
- providing habitat for natural predators of crop pests (such as birds and carnivorous insects);
- maintaining microclimates which assist water retention and quality;
- providing sites for tourism and recreation;
- conserving genetic resources for future development of pharmaceutical or agricultural products; and
- providing timber and other products (such as honey and flowers).
Cultural and social benefits of native vegetation include:
- providing a sense of identity and place; and
- providing places for recreation.