4613.0 - Australia's Environment: Issues and Trends, 2006
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 10/11/2006
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LAND
From 2000 to 2004, Australia's terrestrial protected areas increased by more than 19 million hectares and now extend across almost 81 million hectares or 10.5% of Australia.
FOREST AND GRASSLAND CONVERSION: RATES OF FOREST CONVERSION AND RECLEARING Deforestation is the deliberate removal of forests for the purpose of a change in land use. Deforestation is spatially separated (and unique) from natural effects, such as dieback and fire, and from temporary removals of forest by harvesting. Since European settlement in 1788, vast areas of native vegetation have been cleared or degraded. Associated with the loss of native vegetation are a broad range of environmental, economic, and social impacts. Environmental impacts can include habitat loss or fragmentation, loss of ecosystem, species and genetic diversity, reduced water quality in inland and marine environments, reduced carbon storage, and soil degradation. Economic impacts can include costs associated with loss of flood control, deterioration of water quality, loss of habitat for economically important species, loss of tourist potential, and loss of production through soil degradation. Social impacts can include loss of heritage values and loss of recreation and tourism values. In the decade 1995–2004, although land clearing continued, the rate of forest conversion decreased by more than one-quarter. The figures do not distinguish between the type of vegetation (native or non-native) that was cleared. FOREST AND GRASSLAND CONVERSION, Rates of forest conversion and reclearing
Grazing pressures refers to the effect of grazing by all animals. It not only refers to the impact of domestic livestock such as cattle, sheep and horses but also native and feral grazing animals such as goats, camels, rabbits and kangaroos. The combined effect of grazing places significant pressure on Australia's native flora and fauna. Large areas of native grasslands have been lost either as native species have changed as a result of grazing pressure or as a result of agricultural activity as improved pastures have been introduced to support livestock. Agriculture is the major form of land use in Australia. In 2005, 58% of Australia’s land mass was used for agricultural activity, principally grazing and growing crops. Although numbers of cattle and sheep have not increased in recent times, they still continue to place pressure on the land. The number of cattle increased from about 8 million cattle in 1905 to nearly 28 million in 2005. In 2005, the number of sheep and lambs was 54% higher than in 1905 (about 101 million compared with 66 million). Sheep and lamb numbers in 2005 were considerably lower than in the 1960s, 1970s and late-1980s. The size of the national flock peaked in 1970 at 180 million. It is not just the number or type of grazing animals but also the availability of water that places pressure on Australia's biodiversity. In the arid and semi-arid zones, despite lower stock densities, the impact of grazing on biodiversity can be greater than it is in high rainfall zones because low productivity limits forage and stock compete with native animals for limited resources. Where water was formerly limiting, the provision of water through bore holes, earth tanks and dams, has resulted in grazing pressure spread more evenly across the landscape so there is now little land left that is only lightly grazed. LIVESTOCK GRAZING PRESSURES ALTERED FIRE REGIMESSource: Historical Selected Agriculture Commodities, by State (1861 to present), 2005, (cat. no. 7124.0). Fire has shaped much of Australia’s vegetation. In forest lands, burning is carried out in Australia either anthropogenically or as a result of wildfires. The anthropogenic burning occurs for a variety of reasons including fuel reduction, prevention of uncontrollable wildfires, and traditional burning by Indigenous people. These anthropogenic fires replace wildfires that would occur naturally otherwise, albeit at other times of the year. Some well documented changes as reported in the Australian Government’s State of the Environment 2001 report include:
The spike in the graph in 2003 reflects the widespread wildfires in New South Wales and the Australian Capital Territory in that year. ALTERED FIRE REGIMES Source: Australian Greenhouse Office 2005. National Greenhouse Gas Inventory, 2003 FOREST AREA BY FOREST TYPE, 2003 Forests are important to Australians as a resource for the country's second largest manufacturing industry (forestry and wood products), for biodiversity conservation and as a recreational resource. About one-fifth of the continent is covered in forests. Forests are classified as land with trees with an actual or potential height greater than two metres and 20% crown cover. At the time of European settlement in 1788, it is estimated that Australia's forests covered about one-third of the continent. The area of Australia's forest estate is 164.3 million hectares (ha), of which native forests accounted for 162.7 million ha. While this is an increase in the areas reported since 1998, it largely represents more comprehensive forest mapping of the continent, rather than an actual increase in the area of forest. Current information on woody cover changes indicates that forest cover in Australia is, in fact, decreasing. Although regrowth on cleared agricultural land and establishment of new plantations, farm forestry and environmental planting are occurring, this does not exceed current conversion of forest for other uses such as agriculture and urban expansion (1). Thirteen per cent of Australia's native forests are formally protected in nature conservation reserves, while 70% are privately managed and 7% are available for timber production in multiple-use forests. Plantation forests have increased from an average of 30,000 ha a year in the 1970s to an average of 87,000 ha a year in the period from 1998 to 2003.
ENDNOTES 1. Bureau of Rural Sciences, Australia's State of the Forests Report 2003, p29.
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