Movement ecology of endangered caribou during a COVID-19 mediated pause in winter recreation

The long-term conservation of species at risk relies on numerous, and often concurrent, management actions to support their recovery. Generally, these actions are habitat-based while others are focused on a species' position within its ecological community. Less studied are the impacts from human presence, despite evidence that human activity may reduce the area functionally available for occupancy or resource acquisition. In the winter of 2020/2021, COVID-19-related travel restrictions led to a reduction in helicopter-assisted back-country skiing (heli-skiing). We examined how these reductions in heli-skiing (termed the anthropause) affected the movement ecology and resource selection of southern mountain caribou (Rangifer tarandus caribou) as compared to two prior years (2018/2019 and 2019/2020) and the following year when heli-skiing resumed (2021/2022). We found that home-range size was on average 80–120% larger during the anthropause than in years of normal heli-ski operations. Movement rates also varied among periods, with movement during the anthropause (11.9 km²/day) being higher than in 2019/2020 (7.8 km²/day) and 2021/2022 (8.7 km²/day), though similar to 2018/2019 (12.2 km²/day). Resource selection among periods did not differ, with caribou consistently selecting old forests, high elevations and gentle terrain. These results suggest that back-country recreation, specifically heli-skiing, may be limiting access to resources for southern mountain caribou. This limitation arises through reduced home-range size within suitable late-winter habitat, relative to when heli-skiing is reduced or not occurring – consistent with Encounter Theory. While the demographic effects of reduced home-range size and movement were not examined here, reduced access to resources likely compounds other stressors known to affect population viability of caribou. The results of this study demonstrate the impact that recreation can have on wildlife and highlight the need to consider heli-skiing and other forms of recreation when developing recovery plans.