Mismatch in reindeer resilience to past and future warming signals ongoing declines
Abstract
Rangifer tarandus (caribou or reindeer) survived periods of abrupt climatic warming during the last deglacia-tion but are currently in global decline. Using process- explicit models of likely climate-human-Rangifer inter-actions and inferences of demographic change from radiocarbon- dated fossils and ancient DNA, we reconstructand decipher 21,000 years of Rangifer population dynamics. These high-resolution population reconstruc-tions pinpoint ecological characteristics and life-history traits that most likely enabled Rangifer to surviverapid warming events following the Last Glacial Maximum. Projecting these process- driven models into thefuture reveals that these attributes are unlikely to buffer Rangifer against wide-scale population declines fromexpected 21st Century climatic warming. Our findings highlight a need to boost investments in the manage-ment and conservation of Rangifer, particularly in North America, where projected losses are expected to ex-ceed 80%. This will not only support the survival of the species and the vital services it renders in Arcticecosystems, but also help sustain the socioeconomic, cultural, and emotional well-being of many Rangifer-dependent communities.