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Expansion of conifer woodlands into sagebrush (Artemisia spp.) ecosystems is a primary threat to the greater sage‐grouse (Centrocercus urophasianus) in the Great Basin, southeast Oregon, USA. Conifer removal to restore sage‐grouse habitats has been widely implemented, yet limited information exists on the effects of conifer expansion on sage‐grouse habitat selection. Our objective was to evaluate the landscape‐scale effects of conifer expansion on selection of sites for nesting and to estimate direction, magnitude, and scale of effects. We classified 160 nests and 167 available sites with random forests during 2010–2011 to assess effects of conifer cover and tree clustering at multiple scales along with other vegetation and topographic covariates on selection of nesting habitat. Relative probability of nesting was negatively associated with >3% conifer cover within 800 m of nests. When trees were present within 800 m of nests, sage‐grouse nested where trees were clustered rather than dispersed, suggesting selection for more open habitat. Results further indicated that sage‐grouse are nesting in landscapes susceptible to conifer expansion that have yet to be invaded. Sage‐grouse are expected to lose nesting habitat as conifer expansion continues, but management intervention may be a possible solution to increase habitat availability where open space for nesting is a limiting factor. © 2016 The Wildlife Society.

Counts of males displaying on breeding grounds are the primary management tool used to assess population trends in lekking grouse species. Despite the importance of male lek attendance (i.e., proportion of males on leks available for detection) influencing lek counts, patterns of within season and between season variability in attendance rates are not well understood. We used high‐frequency global positioning system (GPS) telemetry data from male greater sage‐grouse (Centrocercus urophasianus; n = 67) over five lekking seasons (2013–2017) at eight study sites in Nevada to estimate lek attendance rates. Specifically, we recorded daily locations of sage‐grouse in relation to mapped lek boundaries and used generalized additive models to assess temporal variation in attendance rates by age class (subadult vs. adult). Average timing of peak attendance occurred on 16 April but varied from March 16, 2014 to April 21 , 2016. Overall, adult males attended leks at higher rates (0.683 at peak) and earlier in the season (19 March) than subadults (0.421 at peak on April 19). Peak attendance probability was positively related to cumulative winter precipitation. Daily probabilities of lek switching differed between adults (0.019 at peak on March 3) and subadults (0.046 at peak on March 22), and lek switching was negatively related to distance to nearest lek. Our results indicate variable patterns in lek attendance through time, and that lek switching may occur at higher rates than previously thought. We demonstrate the use of generalizable daily attendance curves to date‐correct lek counts and derive estimates of male abundance, although such an approach will likely require the incorporation of information on age structure to produce robust results that are useful for population monitoring.

Sagebrush (Artemisia spp.) obligate wildlife species such as the imperiled greater sage-grouse (Centrocercus urophasianus) face numerous threats including altered ecosystem processes that have led to conifer expansion into shrub-steppe. Conifer removal is accelerating despite a lack of empirical evidence on grouse population response. Using a before-after-control-impact design at the landscape scale, we evaluated effects of conifer removal on two important demographic parameters, annual survival of females and nest survival, by monitoring 219 female sage-grouse and 225 nests in the northern Great Basin from 2010 to 2014. Estimates from the best treatment models showed positive trends in the treatment area relative to the control area resulting in an increase of 6.6% annual female survival and 18.8% nest survival relative to the control area by 2014. Using stochastic simulations of our estimates and published demographics, we estimated a 25% increase in the population growth rate in the treatment area relative to the control area. This is the first study to link sage-grouse demographics with conifer removal and supports recommendations to actively manage conifer expansion for sage-grouse conservation. Sage-grouse have become a primary catalyst for conservation funding to address conifer expansion in the West, and these findings have important implications for other ecosystem services being generated on the wings of species conservation.