Characterization of Dall’s sheep ( <i>Ovis dalli dalli</i> ) post-lambing habitat in Kluane National Park and Reserve based on four decades of population monitoring

Long-term monitoring data are valuable for providing an understanding of habitat consistently used by a species. We used annual aerial survey data collected since 1977 on Dall’s sheep ( Ovis dalli dalli Nelson, 1884) in Kluane National Park and Reserve, Yukon, to describe habitat use by sheep at two spatial scales during the post-lambing period. We used kernel density estimation to map sheep habitat use, followed by random forest modelling with topographic predictor variables to characterize terrain features used most by sheep. Elevation and distance to glacial ice were the two strongest predictors of habitat use, with the most frequently used areas characterized by mid to high elevations not directly adjacent to glacial ice. Relationships differed minimally between ram and nursery groups, suggesting that sexual segregation is due to behaviour and not terrain preference. Kernel density estimation was also used to stratify selection of sites for vegetation surveys to characterize habitat use at a finer scale. Areas used most frequently by sheep were comprised of relatively low growing vegetation. The results provide knowledge useful for management of this iconic species in a rapidly changing environment while demonstrating the value of long-term monitoring data.