Assessing Juniper Woodland Encroachment into the Sagebrush Steppe Ecosystem of Southeastern Idaho for the Protection of the Greater Sage Grouse

Abstract

The landscape of the Western United States is changing rapidly, due to human interventions, climatic factors, and invasive species. In southeastern Idaho the sagebrush steppe is under pressure from all of these forces, including encroaching juniper (Juniperus spp.) woodlands. Due to habitat loss, the Greater Sage Grouse (Centrocercus urophasianus) is currently under consideration for Endangered Species designation, as woodlands threaten their communal breeding grounds known as leks.

In this paper, I assessed the landcover change in southeastern Idaho using data from Landsat 5 Thematic Mapper imagery over a 24-year time frame. Based on landcover classifications from 1987 and 2011, I detected areas of potential woodland encroachment, which was approximately two percent of my 24,000 km2 study site. From the remotely sensed imagery, ArcGIS models were run to determine the vulnerability of leks present in the study site to woodland encroachment. Out of 212 leks within the study area, 26 active leks were within the two-mile range of this landcover change. Finally, management strategies incorporating collaborative efforts between private landowners, non-profit organizations, and federal agencies were outlined to address the restoration of sagebrush landscape and protect the Greater Sage Grouse’s habitat from continued degradation.