Land: Introduction
The quality of land resources in Queensland affects and is affected by human activities. Land is central to human existence and is an essential resource that:
- sustains ecological systems and maintains biodiversity;
- supports food, fibre and mineral production, which contributes to Queensland's economic wealth;
- provides living space and supports recreational activities;
- preserves geological, historical and evolutionary information and materials; and
- has spiritual, inspirational, scientific, cultural and educational value.
The Queensland landscape has been greatly modified since European settlement, providing Queenslanders with primary produce that supports their way of life. The modification of the landscape has, however, also led to many forms of land degradation. The conversion of native vegetated landscapes for more intensive land uses without consideration of natural constraints is a major cause of land degradation. The cumulative environmental impacts of agriculture, grazing, mining, urbanisation and transport degrade the quality of land and vegetation resources. This degradation, in turn, can adversely affect agricultural production and biodiversity and have significant off-site effects.
Changes in land use practices and rehabilitation of degraded land can be achieved, but the restoration of degraded land can be difficult, long-term and expensive. In some cases, the degradation may be irreversible. This chapter discusses the major degradation issues affecting land resources in Queensland. Each issue is discussed in terms of how it affects the landscape, and the current environmental condition is assessed where possible. Management actions that can minimise degradation are explained, and government and community responses are discussed.
Land degradation issues
A number of land degradation issues have negative impacts on soil condition and productivity. These include soil erosion, soil compaction, soil fertility decline, agricultural soil acidification and salinity. Issues such as salinity and the development of acid sulfate soils can also result in substantial damage to infrastructure such as roads, concrete structures and buildings. Reduction in vegetative cover, in particular groundcover, is associated with many of these degradation issues. Such reduction increases the risk of water erosion, and also wind erosion in western Queensland, removing soil materials and thereby further decreasing productivity and increasing off-site impacts, such as a decline in water quality caused by increased sediments and nutrients.
Climate change is discussed in 'Climate and greenhouse' in Chapter 3, Atmosphere. Climate change may become a major driver of land degradation if current management practices continue. Predicted long dry periods in large areas of the state would result in low groundcover because of grazing by cattle and sheep, as well as by native and pest species. If drought is followed by extreme rainfall events then large-scale land degradation through erosion will occur. The potential losses in productivity and declines in biodiversity are matters of great concern, as are the impacts on water quality, including those in the Great Barrier Reef lagoon.
Localised land degradation issues
A number of land degradation issues are not of wide-scale concern, but can have significant local and off-site impacts. Mining disturbance has increased substantially as a result of the enormous growth in the mining sector. Currently the rate of rehabilitation is half the rate of disturbance.
The number of incidences of mass movement has been lower in the 2003-07 reporting period than in 1999-2003 because of low rainfall. A major pressure is urbanisation, following clearing on steeper coastal upland areas. High-intensity rainfall over short periods could see a considerable rise in incidences of mass movement in the future.
The majority of contaminated sites are former industrial land in the near inner city environment. Residential and commercial development on these previously industrial sites has stimulated remediation or removal of hazardous contamination to make the land suitable for the intended purpose. Urban renewal areas in Brisbane that are subject to extensive remediation include Fortitude Valley,
New Farm, Newstead and, more recently, West End.
Significant legislative changes
A number of significant events that have occurred during the current reporting period will see a considerable reduction in pressures on Queensland's land resources.
Broad-scale tree clearing of remnant vegetation in Queensland is likely to have ended in December 2006 when clearing permits expired. This is a major achievement and has positive implications for biodiversity and degradation issues, such as salinity, soil condition decline, erosion and declining water quality. This is discussed further in 'Habitat protection' in Chapter 7, Biodiversity.
Population growth continues to be one of the major pressures on the land, in particular in south-east Queensland, but also in other coastal areas. The implementation of the South East Queensland Regional Plan in 2005 is an important step in mitigating the negative impacts of the state's increasing population by limiting urban expansion to defined zones and protecting open spaces and important land resources. For further information, see 'Population and settlement patterns' in Chapter 9, Human settlements.
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Last reviewed 16 May 2011
Last updated 4 September 2007