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

Abstract

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 (<1,000 meters above sea level) equating to 1 to 12 unique haplotypes being at risk under climate scenarios projecting 1°C and 2–3°C increases respectfully in global temperature by 2070. Main conclusions Our results suggest that historical range expansion and retraction processes by a cold‐adapted mountain species caused diversification between populations, resulting in unique genetic diversity which may be at risk if distributions of cold‐adapted species shrink in future. Assisted colonizations of individuals from at‐risk populations into climatically suitable unoccupied habitat might help conserve unique genetic diversity, and translocations into remaining populations might increase their genetic diversity and hence their ability to adapt to future climate change.

Population decline at distribution margins: Assessing extinction risk in the last glacial relictual but still functional metapopulation of a European butterfly

“…Using ecological modelling and genetic demographic inferences, we found evidence for a unique Western glacial refuge for C. hero in Europe. Our finding is therefore a contribution to the ever-growing literature showing that many species, including butterflies, survived the LGM in Western Europe outside the Mediterranean peninsulas and that boreal species did not necessarily had a far-east Siberian refuge (Després et al, 2019;Minter et al, 2020). A second larger…”

Low winter precipitation, but not warm autumns and springs, threatens mountain butterflies in middle-high mountains

“…Besides J and K, it inhabits the mountains of Scotland and northern England, Cantabrian Mts in Spain, the Harz Mts in Germany (extinct), the Pyrenees, Massif Central and Vosges in France, Central Apennines in Italy, Alps, Carpathians, and the Dinaric mountains of the Balkans southward to northernmost Greece ( Hinojosa et al, 2018 , see Minter et al, 2020 ). The populations of particular mountain regions are genetically unique ( Minter et al, 2020 ). Across this range, it prefers Nardus dominated grasslands on nutrient-poor bedrock ( Ewing et al, 2020 ).…”

The isolated Erebia pandrose Apennine population is genetically unique and endangered by climate change

“…In the case of Erebia , a recent study on E . epiphron showed that climatic changes are expected to erode the genetic diversity of this species considerably (Minter et al ., 2020). This is likely to happen in the southern margins of its distribution (Minter et al ., 2020) where genetic richness is higher due to the long‐term persistence of this genus during Pleistocene climatic fluctuations (Dincă et al ., 2021).…”