In Brief | Land
State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.
This is a summary of Australia state of the environment 2011, which is an independent report presented to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities by the State of the Environment 2011 Committee
We use land in various ways, and land use is changing in response to new priorities and new pressures.
We use our land for livestock grazing, agriculture, forestry, urban and residential development, mining, waste disposal and infrastructure. Livestock grazing is the land use of greatest extent, accounting for 55% of Australia's land area. The areas managed for conservation and by Indigenous Australians have expanded and are the second most common land uses (each now more than 20% of Australia's land area).
Australia's land environment is threatened by widespread pressures.
Invasive species, inappropriate fire patterns and grazing have a significant impact on much of our land environment. The environmental impact of grazing appears to be mixed, with impacts diminished in some regions but increased in others since widespread monitoring began in 1992.
Threats to our soil, including acidification, erosion and the loss of soil carbon, will increasingly affect Australia's agriculture unless carefully managed.
Acidification and erosion currently affect large areas, although wind erosion has decreased in response to better agricultural practices. In 2001, it was estimated that soil acidity affected 50 million hectares of surface layers and 23 million hectares of subsoil layers, estimated to cost $1.585 billion per year in lost agricultural production. Soil carbon is central to maintaining soil health and fertility, and soil can also be a significant source or sink for greenhouse gases, depending on land management. Soil carbon stocks are low in many Australian agricultural systems.
Management effectiveness of the land environment varies.
The effectiveness of our management of the land environment varies with land use and the nature of the pressures on the environment. The nature of widespread, landscape–scale pressures and resource constraints often makes it difficult to manage more extensive land uses and pressures as effectively as we would wish. A notable exception during the past decade is the large and widespread reduction in tillage intensity across the cropping lands of Australia.
The rate of land clearing, one of the most significant pressures affecting the land environment, is slowing, but still averaged around one million hectares each year over the decade to 2010.
Land clearing and ecosystem fragmentation are associated with the expansion of both agriculture and settlements, and are concentrated in a relatively small number of regions. The legacy impacts of land clearing are substantial, with loss and fragmentation of native vegetation. By the end of the decade, the continental extent of land clearing was balanced by the extent of regrowth–although the character and values of the original and regrowth vegetation are often different.
Governance and institutional arrangements for management of the land environment need improvement, and levels of investment are inadequate.
Governance and institutional arrangements have changed significantly since 2006, and are not yet optimal in a number of important respects. Although substantial, the levels of investment in management of the land environment—and in the research, development, knowledge and information systems that underpin management—remain inadequate for soundly based adaptive management.
Climate change is expected to bring about profound changes in the Australian land environment, particularly native vegetation and production systems.
Some native vegetation communities are likely to disappear completely; the extent and distribution of others are likely to change significantly; and novel ecosystems are expected to arise. These changes will affect other environmental and production values.
We have made progress in many aspects of managing Australia's land environment. However, the trends for many indicators of land environmental values remain adverse. Although soils and vegetation are in relatively good condition across large areas of Australia, this is not the case in much of the intensive land–use zone where agricultural production is concentrated, nor in some parts of the rangelands. While land–management practices have improved during the past few decades, in agricultural systems the loss of soil carbon, and soil acidification and erosion, are problematic and may have major impacts on production.
The management and monitoring of soil carbon is a matter of national and international importance. The carbon content of soil is a key indicator of its health, and is a master variable that controls many processes (e.g. nutrient cycling, development of soil structure, water storage). Few regions have increasing levels of soil carbon, although the potential in the savanna landscapes of northern Australia is significant. Depending on how soils are managed, they can be a significant source or sink for greenhouse gases.
Soil acidification affects about half of Australia's agriculturally productive soils. Its severity and extent are increasing, and large areas will become unproductive and degraded. Soil acidification also looms as a major constraint on Australia's capacity to increase carbon in agricultural soils.
The widespread adoption of minimum tillage in agriculture during the past decade is a major achievement by Australian farmers that reduces pressures affecting the land environment. However, current rates of soil erosion by water across much of Australia exceed soil formation rates by a factor of at least several hundred and, in some areas, several thousand. The latter areas will be severely degraded in less than a century. However, the rate of wind erosion during the recent drought in southern Australia was less than 20% of that during the 'dust bowl years' of the 1940s.
The longer settled agricultural and coastal zones have the highest concentration of impacts on native vegetation. In most of these regions, less than 50% of native vegetation remains, and vegetation condition generally deteriorates with diminishing remnant extent. Approximately 13% of native vegetation nationally has been completely converted to other uses.
Annual rates of native vegetation clearing averaged around one million hectares in the decade to 2010, balanced by the extent of regrowth by the end of the decade. The condition of much native vegetation is deteriorating, particularly that remaining as fragmented remnants in intensive and settled landuse zones, and that subjected to persistent pressures such as inappropriate grazing or fire regimes. Land clearing and ecosystem fragmentation associated with the expansion of both agriculture and settlements are concentrated in a relatively small number of regions.
The impacts of climate change on the land environment are already being seen, and are expected to be profound. By 2070, many environments will differ markedly from those that currently exist. Some vegetation communities will disappear, others will change significantly in extent and distribution, and novel ecosystems will arise. Many agricultural and production systems, including forestry, are likely to be significantly adversely affected.
Widespread landscape-scale pressures–particularly those due to invasive species and inappropriate fire regimes–continue to threaten land environmental values across much of Australia. These pressures are likely to be exacerbated by climate change. The impacts of these pressures are particularly pronounced on the extensively managed environments of northern Australia.
Livestock grazing is the most extensive of Australia's land uses, practised across 55% of the continent. Pressures on the land environment associated with livestock grazing are mixed; they appear to be diminishing in some regions, but increasing in others. Although better management of many agricultural systems has reduced their impacts on the land environment, a number of issues around nutrient and soil management remain. Acidification and loss of soil carbon are major risks to our agricultural production systems. Management of both native and plantation production forests has become more regulated, and landscape–scale impacts are generally small.
Urban and peri–urban expansion, particularly around major cities and in some coastal regions, continues to adversely impact land environmental values. New forms of mining are generating pressures on the land environment, and conflicting with other land uses, notably agriculture, in some regions.
Most of Australia's land environment is managed by one of three groups: state and territory agencies responsible for public land of various tenures, family and corporate agricultural and pastoral businesses, and Indigenous Australians.
The effectiveness of our management of the land environment varies with land use and the nature of the pressures on the land environment. The effectiveness of management has improved for most land uses, particularly those that are most intensive, but needs to improve further in many land-use systems to protect and sustain their environmental values. Because of the nature of widespread landscape–scale pressures and resource constraints, it is often difficult to manage more extensive land uses and pressures as effectively as we would wish. As a consequence, management outcomes for many forms of land use and in response to many pressures are trending downward.
Although substantial, investment remains inadequate in management of the land environment, and in the research and development programs and knowledge and information systems that underpin good land management. Australia's investments in natural resource management appear to be less on a perhectare basis (of agricultural land) than in Europe or the United States, and are generally regarded as inadequate to meet Australia's environmental management needs.
There is also a serious gap in both the professional and the technical capacity necessary for effective land management. This gap will increase and its consequences become more acute as we face the challenges that climate change will bring to land environmental values and production systems.
The outlook for Australia's land environment is mixed. It depends on the conjunction of past, current and future pressures, and how we manage them.
Future land environments are likely to be shaped by a different climate from that experienced in Australia's human history. This is expected to have profound impacts on our land environment. Australia's land environment will also be subject to increasing land–use competition, including between human settlements; conservation; and food, fibre and energy production.
We have much of the knowledge and experience required to better manage our land environment, and have been doing so in many respects. However, the trends in many indicators of land environmental values are negative, and are likely to be exacerbated by climate change. Realising a more positive outlook for Australia's land environment will require renewed resolve, effort and investment.