干旱区生态环境知识资源中心

There is a growing trend in Australia and other developed countries for de-intensification of animal production from grasslands and for grasslands to be used for purposes other than livestock grazing. These shifts are occurring for a variety of reasons including unsustainable land management practices, environmental pollution, loss of conservation value, poor commodity prices and declining rural infra-structure and communities. In Australia, the shifts are under way in agricultural grasslands, where sown pastures occur in a matrix of semi-natural woodlands, but less so in the other three major natural grasslands that forms the and and semi-arid rangelands.

The conversion of natural wooded grasslands to agricultural grasslands, often involving crop/pasture rotations, began over 100 years ago in those regions of Australia where rainfall was sufficiently high and regular to allow cropping and pasture sowing. Later, agricultural research identified soil nutrient deficiencies, found European and African grasses and legumes to utilise the raised fertility and developed machines that raised the scale and efficiency of livestock production. Governments promoted pasture improvement, and with livestock breeding, fibre and meat production per hectare was significantly raised. The Australian people in general, accepted as worthwhile and successful the conversion to agricultural grasslands. Conquering the "bush", taming nature and establishing livestock grazing businesses were seen to be appropriate activities for rural pioneers and later generations.

However, doubts about the long-term sustainability of livestock grazing businesses on agricultural grasslands and to a lesser extent other natural grasslands, have grown in the minds of scientists and pastoralists and now the public. Salt has risen to the surface in many regions from tree removal changing hydrological processes. Soils have poor structure and low potential productivity. Added nutrients and chemicals are moving off property with undesirable and public consequences eg toxic algal blooms in rivers. Significant species extinction within Australia's unique plants and animals are linked to land clearing and pastoral management; survival of many threatened species is problematic. Persistent low commodity prices for traditional products are making many livestock grazing businesses untenable. Rural communities are struggling to survive with the withdrawal of services by Government and major businesses.

These problems are being addressed across many fronts. Foremost there is a substantial and growing ownership of the problems by rural communities through "Landcare" and catchment management groups. Research into the sustainability of low-input native pasture systems, the spatial requirements for remnant and plantation vegetation (amount, location and continuity) to lower water tables, ecosystem services and processes involving native plants and animals, effective mechanisms for knowledge sharing and alternative land uses are underway.