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Land-use Effects on Ecosystems

Soil stability is a primary control over the fertility, productivity, and sustainability of managed ecosystems in arid and semi-arid parts of the United States. Most arid/semi-arid lands have sparse vegetation cover, and low surface-soil organic matter content. Disturbance to surface soils by activities such as grazing can influence arid-land ecosystem fertility in many ways including through the alteration of vegetation cover, soil physical properties, Carbon cycling, and hydrologic properties. Unlike wetter environments, deserts are particularly susceptible to wind erosion. Many desert surfaces are protected from wind and water erosion by only a thin and fragile layer of physical or biological soil crusts (BSC). When these crusts are broken, the underlying soil is exposed to runoff and wind, thereby becoming vulnerable to agents of erosion (see photo below). Our studies focus on developing an understanding of both historical and ongoing grazing impacts on arid ecosystems.

Dust and sand blowing across grazed area of Dugout Ranch near Canyonlands National Park in June 2002.