Impact of past climate warming on genomic diversity and demographic history of collared lemmings across the Eurasian Arctic

Significance Ongoing climate warming significantly impacts cold-adapted Arctic biota. One way to predict the biological consequences of Arctic warming in the future is to investigate biotic responses to past warming events. We use variation in mitochondrial and nuclear genomes in the collared lemming, a keystone species of the food web in tundra, to reconstruct demographic changes as a response to warming of the last interglacial and Holocene thermal optimum. We show that environmental change during Late Quaternary climate warming contracted distribution range, reduced effective population size, and decreased genetic diversity across the Eurasian Arctic except for West Beringia, a region in the extreme northeast of Eurasia. Thus, West Beringia represents a potential refugium for terrestrial Arctic species under ongoing climate warming.