Modeled effects of sagebrush-steppe restoration on Greater Sage-Grouse in the interior Columbia Basin, USA

Habitats of Greater Sage-Grouse (Centrocercus urophasianus) have declined across western North America, and most remaining habitats occur on lands administered by the U.S. Forest Service (FS) and U.S. Bureau of Land Management (BLM). Consequently, managers of FS-BLM lands need effective strategies to recover sagebrush (Artemisia spp.) habitats on which this species depends. In response to this need, we evaluated the potential benefits of two restoration scenarios on Greater Sage-Grouse in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States. Scenario 1 assumed a 50% reduction in detrimental grazing effects (through changes in stocking rates and grazing systems) and a six-fold increase in areas treated with active restoration (e.g., prescribed burning, native seedings, wildfire suppression) compared with future management proposed by the FS-BLM. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same increase in active restoration as scenario 1. To evaluate benefits, we estimated the risk of population extirpation for sage grouse 100 years in the future under the two scenarios and compared this risk with that estimated for proposed (100-year) FS-BLM management. We used estimates of extirpation risk for historical (circa 1850-1890) and current time periods as a context for our comparison. Under historical conditions, risk of extirpation was very low on FS-BLM lands, but increased to a moderate probability under current conditions. Under proposed FS-BLM management, risk of extirpation on FS-BLM lands increased to a high probability 100 years in the future. Benefits of the two restoration scenarios, however, constrained the future risk of extirpation to a moderate probability. Our results suggest that expansive and sustained habitat restoration can maintain desired conditions and reduce future extirpation risk for sage grouse on FS-BLM lands in western North America. The continued spread of exotic plants, however, presents a formidable challenge to successful restoration and warrants substantial research and management attention.