Projecting Future Changes in Sagebrush Distribution in the Great Basin

Changes to the Great Basin landscape are due to the singular or interactive effects of numerous drivers including climate change. These changes may be significantly reducing or altering the quality of wildlife habitat, rates and pathways of nutrient, water, and energy flows, and the quality and quantity of ecosystem goods and services the landscape produces. A pilot study was initiated to evaluate approaches to assess the causative factors for changes in landcover for a 250-sq kilometer area surrounding Great Basin National Park. Landsat-derived landcover change at ~5 year intervals from 1985-2007 were analyzed to detect transitions in sagebrush communities either to or from cold desert scrub or pinyon-juniper communities. These transitions were then evaluated with regard to the climatic and hydrologic conditions that corresponded to changes in these communities to define “bioclimatic envelopes” for each community type that could be used to anticipate future changes in vegetation distribution. Downscaled future climate scenarios were then used with a regional hydrologic model to project future bioclimatic envelopes across the study region to provide an estimate of the direction and trend of actual landcover change in the study area, and to quantify the relative influence of each ecohydrologic driver or interaction among drivers. Refinement of this approach and extension to the entire Great Basin region will provide tools and information for regional land and resource management in the face of a changing climate.