Predicting plant community susceptibility to invasion by introduced species and determining mechanisms of resistance are fundamental concerns of ecology and ecosystem management. In the Great Basin, the invasive introduced annual cheatgrass (Bromus tectorum) currently dominates 3 million acres, with another 14 million acres heavily infested and 60 million acres considered at risk for potential domination.

Cheatgrass has greatly altered the community and fire dynamics of Great Basin rangelands. For example, invasion reduces wildlife habitat, accelerates erosion, provides unpredictable forage for livestock, and creates a fire hazard: dominance by this exotic annual grass fueled over 70% of the large fires (>5000 acres) in the Great Basin from 1980-1995.

However, the eastern portion of the Snake River Plain, including the Idaho National Laboratory (INL), has largely escaped the cheatgrass dominance found in the western portions of the Snake River Plain and to the south in northern Nevada. This interesting exception to the pattern of cheatgrass invasion provides a unique opportunity to identify environmental conditions, community characteristics, or management practices conferring ecosystem resistance to invasion.

Understanding the mechanisms underlying resistance to cheatgrass invasion will support the conservation and management of Great Basin rangelands, help minimize the risk of dominance by cheatgrass, and provide an understanding of the processes of biological invasion and vegetation change, facilitating conservation and restoration.