Earth, air, fire and water: distinguishing human impacts from natural desertification in South Australia

Abstract

Gully erosion in southern Australia has been widely and correctly considered as one of the more obvious signs of accelerated soil loss brought about by human mismanagement since the 1860s. However, humans were not responsible for initiating many of the gullies in the dissected uplands of South Australia. In the Flinders Ranges, for example, the current cycle of gully erosion began 15,000 years ago, and was caused by a change in climate. This change was reflected in a reduction in dust storms and an increase in runoff from bare rocky slopes that were previously mantled in a layer of reworked wind-blown dust characterised by high rates of infiltration and low rates of runoff. Such processes are best considered as ‘natural desertification’.