Past, current, and potential future distributions of unique genetic diversity in a cold‐adapted mountain butterfly

Aim Climatic changes throughout the Pleistocene have strongly modified species distributions. We examine how these range shifts have affected the genetic diversity of a montane butterfly species and whether the genetic diversity in the extant populations is threatened by future climate change. Location Europe. Taxon Erebia epiphron Lepidoptera: Nymphalidae. Methods We analyzed mtDNA to map current genetic diversity and differentiation of E. epiphron across Europe to identify population refugia and postglacial range shifts. We used species distribution modeling (SDM) to hindcast distributions over the last 21,000 years to identify source locations of extant populations and to project distributions into the future (2070) to predict potential losses in genetic diversity. Results We found substantial genetic diversity unique to specific regions within Europe (total number of haplotypes = 31, number of unique haplotypes = 27, H d = 0.9). Genetic data and SDM hindcasting suggest long‐term separation and survival of discrete populations. Particularly, high rates of unique diversity in postglacially colonized sites in England (H d = 0.64) suggest this population was colonized from a now extinct cryptic refugium. Under future climate change, SDMs predict loss of climate suitability for E. epiphron, particularly at lower elevations (
The genetic diversification of cold‐adapted mountain species, such as E. epiphron, has been shaped by Pleistocene glaciations, resulting in unique genetic diversity in isolated populations. The unique genetic diversity in mountain and cold‐adapted species is at under future climate warming, and we predict E. epiphron will lose 38%–64% of its range in the future, resulting in the loss of genetic diversity, reducing its ability to adapt.