The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

TitleThe impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia
Publication TypeConference Proceedings
Year of Publication2012
AuthorsAubault H, Webb N, Scanlan JC, Strong C, Leys J
Conference NameAustralian Rangeland Society 17th Biennial Conference
Volumep. 60
Date Published09/2012
PublisherAustralian Rangeland Society
Conference LocationKununurra, Western Australia
ARIS Log Number295995
KeywordsGRASP, land degradation, management, modelling, stocking rate, wind erosion

An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosion (their erodibility) is highly sensitive to changes in vegetation cover and soil properties like crusting and aggregation, which control the area of bare ground exposed to erosive winds, and the availability of fine erodible sediment. Pastoralism, including the production of cattle and sheep, is thought to modify these controls through its impacts on vegetation cover and soil surface properties. However, research is yet to quantify the impact of grazing land management on the erodibility of rangelands, or how these impacts vary between land types. We present a simulation analysis that implements the Australian Land Erodibility Model (AUSLEM) in line with a pasture growth and animal production model (GRASP) to evaluate the impacts of grazing management on the erodibility of 5 land types in western Queensland. The study has tested separately the effects of stocking rates, stocking strategies and land condition on wind erodibility. Our results show that wind erodibility increases with stocking rate, showing a nonlinear response that varies in intensity between land types. Susceptibility of the land types to wind erosion is shown to increase under stocking strategies that lack flexibility or the capacity to rapidly destock in response to drought conditions. However, moving from high stocking rates under a fixed stocking to a more flexible strategy is shown to have a greater effect on erodibility than differences between flexible stocking strategies based around the long term safe stocking rates. The degradation of land condition results in an increase of wind erodibility with an abrupt change of rates representing major shifts in environmental conditions. The analysis indicates that historical stocking rates have had a high impact on wind erodibility; however, under the current stocking rate, impacts on wind erodibility are reduced. Wind erodibility can be reduced by adopting a conservative management with low stocking rates as well as maintaining the land in good condition.