Forestry disturbances facilitate habitat loss for endangered southern mountain caribou in the Columbia Mountains, Canada

Effective conservation of at-risk, wide-ranging mammals in human-disturbed landscapes requires management decisions grounded in evidence of how animals use landscapes, particularly areas critical for persistence and recovery. An ecotype of woodland caribou, the southern mountain caribou ( Rangifer tarandus caribou ), is being extirpated in Canada despite federal and provincial legislative and policy protections. The ultimate cause of population declines is habitat destruction, yet protection is stymied by the absence of current habitat quality maps across southern mountain caribou herd extents. We identify drivers of habitat selection and predict key habitats for five southern mountain caribou herds in the Columbia Mountains, British Columbia, one of which became extirpated during this analysis. We modeled caribou resource selection in early winter, late winter, spring calving, and summer under a mixed-effects regression framework using accessible public data of natural features and disturbance threats. We then produced third-order spatial predictions of habitat quality. Seasonal caribou migrations show differences in elevation, canopy closure, and biogeoclimatic zones. Caribou select old growth forest (>140 years) during calving and forest stands greater than 75 years old in all other seasons. We identified a threshold forestry road density value where relative probability of use declines to half: 0.78 km/km 2 (late winter), 1.05 km/km 2 (calving), 1.08 km/km 2 (summer). Effective conservation of southern mountain caribou requires consideration of forestry-related disturbance and seasonal variation in caribou habitat use to accurately identify and protect key habitats. Protecting mature and old-growth forests and restoring roads are urgently needed measures to maintain caribou in this landscape.