Greater sage-grouse roost site relative abundance in the Wyoming Basins Ecoregional Assessment area

Greater sage-grouse (Centrocercus urophasianus) have been declining both spatially and numerically throughout their range due to anthropogenic disturbance and loss and fragmentation of sagebrush (Artemisia spp.) habitats. Understanding how sage-grouse respond to these habitat alterations and disturbances, particularly the types of disturbances and extent at which they respond, is critical to designing management actions and prioritizing areas of conservation. To address these needs, we developed this spatially explict model of the relationship between occurrence and abundance of greater sage-grouse and multi-scaled measures of vegetation, abiotic, and disturbance in the Wyoming Basins Ecoregional Assessment (WBEA) area. Sage-grouse occurrence was strongly related to the amount of sagebrush within 1 km. Proximity to anthropogenic disturbance including energy development, power lines, and major roads was negatively associated with sage-grouse occurrence. Roost sites were identified by presence of sage-grouse fecal pellet groups. The information here was developed using a generalized ordered logistic regression with study sites assigned into absent, low, and high abundance classes. The models for low and high abundance were combined into a three-class relative abundance surface (absent, low, and high). The bin breakpoint separating absent from low/high abundance habitat was based on the sensitivity-specificity equality threshold to maximize prediction success for each model. Within low/high abundance habitat, the threshold was set at the point where the predicted probability of being high abundance habitat exceeded the probability of being low abundance habitat This map correctly predicted active lek locations as either low or high abundance with >75% accuracy and the mean number of sage-grouse at leks increased with each class (Absent: 19.16 males, Low: 34.44 males, High: 57.11 males).