The influence of environmental conditions on the selection of spring migration routes by caribou

Abstract Animal migrations influence key ecological processes such as predator–prey dynamics, nutrient and energy cycling, and community structure. Long‐distance migrations are declining worldwide, and a better understanding of the factors influencing animal space use during migrations is essential to maintain this behavior in the wild. We mapped the spring migration routes used by female caribou of the declining Rivière‐aux‐Feuilles herd in northern Québec, Canada, from 1994 to 2019. We used resource selection functions to determine the effect of remotely sensed measures of snow depth, precipitation, elevation, and land cover classes on habitat selection along 811 migration routes used by 304 individuals. We further explored whether observed trends in the geographic position of migration routes (e.g., mean longitude, mean variance of longitude) influenced calf recruitment the following fall. Female caribou selected areas with deeper snow, less precipitation, and lower elevation, avoided forest and lichen heath, and selected more strongly erect‐shrub tundra and waterbodies than the reference category, shrub tundra. A cluster analysis revealed different migration patterns, with migration routes in the early 2000s being more restricted in space and located further inland than routes in the 2010s. The location of spring migration routes was unrelated to changes in calf recruitment. The characterization of migration routes used by caribou will help inform management and could be used to predict future herd movements in response to different climate change scenarios.