Local weather interacts with human disturbances to shape the behaviour of boreal caribou across a large climate gradient

Climate change, a growing threat to global biodiversity, is expected to interact with other drivers of decline of species at risk. Although its long-term effects are uncertain, climate change is influencing the behaviour, distribution, and interspecific interactions of many species. The boreal caribou (Rangifer tarandus caribou) is listed as Threatened in Canada, and its decline is driven by the alteration of habitat resulting from anthropogenic disturbances. However, some evidence suggests that the decline could be accelerated by climate change. We studied the influence of local weather conditions, as a proxy of variation in climate, on the behaviour of 10 populations of caribou found across broad gradients of climate and anthropogenic disturbance. We used GPS-collar locations from 214 caribou in Quebec and 195 in British Columbia to develop resource selection functions describing the effect of the interaction of local weather and anthropogenic disturbance on habitat selection. Our results suggested that some components of weather (i.e., temperature, precipitation, snow density and snow depth) influenced the seasonal behavioural responses of caribou to anthropogenic disturbance. Similar patterns of response were found for populations in Quebec and British Columbia, although some responses differed among seasons and the anthropogenic activities faced by caribou within the two provinces. Although our results suggested a certain level of plasticity among populations, local weather conditions shaped the behavioural response of caribou to habitat disturbances. Future climate change, in combination with human activities, could further influence the habitat selection of boreal caribou in Canada, with implications for population recovery.