Pacific Southwest Research Station

Predictive modeling of cheatgrass invasion risk for the Lake Tahoe Basin

Principal Investigators:
Brian Anacker, University of California-Davis
Susan Harrison, University of California-Davis
Hugh Safford, USDA Forest Service-Region 5, Pacific Southwest Region

Proposal [pdf]

Final Report [pdf]

Please contact Dr. Brian Anacker with questions regarding the final report.

Project Summary

Cheatgrass (Bromus tectorum) is an exotic species of major concern in the Lake Tahoe Basin, and may prove to be the first exotic plant to become highly invasive and dramatically alter native-dominated communities within the basin. While it is increasingly detected in the basin, it is still at an early stage of invasion in comparison to lower elevation sites outside of the basin to the east.

This project examined the relationship between climate and the invasion of cheatgrass. In an effort to forecast if climate change and disturbance will trigger further cheatgrass establishment and spread, the environmental factors related to current cheatgrass distribution and abundance in the basin were modeled. A spatially-explicit predictive risk model of cheatgrass invasion was developed and applied under both the current climate and future climate scenarios. Disturbance parameters for disturbance were incorporated to improve model accuracy and predictive value.

The resulting information will be useful for creating management scenarios to resist species invasion, restore natural communities, and sustain biodiversity and ecosystem function in the face of changing climate.