Greater Sage‐Grouse Centrocercus urophasianus Use of Threetip Sagebrush Relative to Big Sagebrush in South‐Central Idaho

Abstract

Disturbances that change sagebrush Artemisia spp.‐steppe communities may have an impact on greater sage‐grouse Centrocercus urophasianus populations. Fire can rapidly alter sagebrush‐steppe communities and may result in an increase in threetip sagebrush A. tripartita because this shrub is one of the few species of sagebrush that will sprout following fire. We examined the use of threetip sagebrush by sage‐grouse as nest cover and compared nest success of grouse using threetip sagebrush to that of grouse using big sagebrush A. tridentata. Sage‐grouse used threetip sagebrush as nest cover less than expected based on the abundance of this shrub. The only other species of sagebrush used as nest cover was big sagebrush, and sage‐grouse used big sagebrush more than expected based on big sagebrush abundance. However, nest site selection was confounded by age of sage‐grouse females. Sage‐grouse that used big sagebrush as nest cover had greater nest success than grouse using threetip sagebrush. Our findings demonstrate another negative, but subtle, effect of fire on sage‐grouse populations and further underscore the need for fire suppression and carefully implemented habitat rehabilitation projects.