Indicators of Catchment Condition in the Intensive Land Use Zone of Australia – Intensive agricultural area

It should be noted that this data is now somwhat dated!

Areas of intensive agriculture and production forestry are typically areas where a monoculture land-use has replaced a more biologically diverse system. The loss of biodiversity through agriculture is not something that can be easily reversed through planning and management. Remaining areas of native habitat are sensitive to catchment land-use changes.

An intensive agricultural land-use coverage was obtained from the NLWR (2000) National Land-Use map (1:1M). Intensive agriculture was mapped as all areas with cropping or modified pasture systems.

The scale of the land-use map is relatively coarse and the data has been compiled from SL land-use data mapped to grid cells based on satellite imagery interpretation. Reliability is variable. Intensive agriculture and plantation forestry cause a dramatic reduction in biodiversity. By definition, the ecological integrity of an area where a monoculture dominants, is poor; the indicator is unequivocal. Less intensive agriculture also undermines biodiversity, but arguably not to the extent found in cropping and improved pasture systems.

The indicator has not been validated against biotic function, but is an indicator that is easily understood by users. Whilst a substantial impact of intensive agriculture is on biotic condition it can also impact on waterways (water extraction and chemical transfer), and on soil structure (the ability of the soil to avoid hard packing or erosion). Intensive agriculture coincides with good soils on gently sloping or flat land, in higher rainfall areas, or where water is available for irrigation.

The 500 km2 and 5A5 km scale maps give a well recognisable expression of the intensive agriculture areas of Australia. Major impacts on catchment condition are well expressed in the AWRC map. Impact on catchment condition are seen for parts of central and southern Queensland, the western slopes and plains of New South Wales, throughout most of southern and south-eastern South Australia, central and northern Tasmania, most of Victoria and south-western Western Australia.Data are available as:

• continental maps at 5km (0.05 deg) cell resolution for the ILZ;
• spatial averages over CRES defined catchments (CRES, 2000) in the ILZ;
• spatial averages over the AWRC river basins in the ILZ.

See further metadata for more detail.