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Item Greater sage‐grouse habitat selection varies across the marginal habitat of its lagging range margin(Wiley, 2022-07) Beers, Aidan T.; Frey, Shandra N.Studying wildlife–habitat relationships at the edges of their range can provide valuable insights into the environmental factors limiting wildlife distributions and most likely to drive extirpations and range shifts in response to landscape change. Yet the relative impact of those factors is likely different along the range margin, so it is important to identify the limitations to suitable habitat at both regional and local scales. Some of the most drastic impacts of large-scale landscape changes in North America have occurred and are forecasted in the sagebrush steppe ecosystems, where species unable to seek new habitat in the fragmented landscape will be vulnerable to climatic extremes, vegetation community shifts, and anthropogenic land use change. One of the species likely under major threat from landscape changes is the greater sage-grouse (Centrocercus urophasianus), a sagebrush obligate with habitat constraints that make it susceptible to habitat loss impacts as sagebrush systems contract and fragment at their southern range margin, already naturally fragmented. In this study, we evaluated factors of topography and land cover directly impacting habitat selection by sage-grouse in four study areas along their lagging range edge. We used >116,000 GPS locations from >90 grouse across four study areas in southern Utah and Nevada from 2014 to 2020 in habitat selection analyses using random forest models. Our results showed that sage-grouse exploit topography and sagebrush cover, possibly to break predator sight lines and moderate the risk posed by avian predators using tree perches, complicating the effects of tree cover and conifer encroachment into sagebrush habitat. We found similar trends across all four study areas, suggesting sage-grouse along the southern range margin face similar limitations. However, the effects were nonlinear and varied—models trained in one study area were only moderately successful at predicting selection in others. The local idiosyncrasies along this southern range margin indicate a need for place-based conservation for sage-grouse and other potentially imperiled species. Incorporating new understandings of local impacts will refine regional and range-wide models and support efforts to effectively create habitat and plan for range shifts by vulnerable species in response to environmental change.Item Evaluating the importance of wolverine habitat predictors using a machine learning method(Oxford University Press, 2021-12) Carroll, Kathleen A.; Hansen, Andrew J.; Inman, Robert M.; Lawrence, Rick L.In the conterminous United States, wolverines (Gulo gulo) occupy semi-isolated patches of subalpine habitats at naturally low densities. Determining how to model wolverine habitat, particularly across multiple scales, can contribute greatly to wolverine conservation efforts. We used the machine-learning algorithm random forest to determine how a novel analysis approach compared to the existing literature for future wolverine conservation efforts. We also determined how well a small suite of variables explained wolverine habitat use patterns at the second- and third-order selection scale by sex. We found that the importance of habitat covariates differed slightly by sex and selection scales. Snow water equivalent, distance to high-elevation talus, and latitude-adjusted elevation were the driving selective forces for wolverines across the Greater Yellowstone Ecosystem at both selection orders but performed better at the second order. Overall, our results indicate that wolverine habitat selection is, in large part, broadly explained by high-elevation structural features, and this confirms existing data. Our results suggest that for third-order analyses, additional fine-scale habitat data are necessary.