Living on the edge—Genomic and ecological delineation of cryptic lineages in the high‐elevation specialist Erebia nivalis

Abstract

Cold‐adapted species at high elevations may be especially impacted by global warming since they may be limited in their capacity to adapt to changing conditions or may be prevented from shifting their distributions upwards if no suitable habitats are available. The latter may be true for Erebia nivalis, a high‐elevation specialist that mainly occurs in the Austrian Alps and on few mountaintops in Switzerland, where its taxonomic and conservation status remains unclear. We aimed to clarify the relationships among geographically isolated populations of E. nivalis using whole‐genome resequencing data to reconstruct population connectivity and phylogenetic relationships. We inferred current and historical effective population sizes and combined these with tests for ecological differentiation based on available occurrence data to re‐evaluate the conservation status of E. nivalis. Our results confirm that Swiss and Austrian E. nivalis should be considered different evolutionarily significant units for conservation purposes, as they are marked by moderate genomic differentiation, distinct demographic histories and a difference in the abiotic conditions of their habitats. In both Austria and Switzerland, we found rapid uphill range shifts over the last decades, little population connectivity, low current effective population sizes and low genetic diversity. The above, combined with the low dispersal capacity of this 2‐year lifecycle species and its need to overwinter under snow, which is rapidly retreating from several regions of the Alps, leads us to suggest that the status of E. nivalis should be updated to ‘Vulnerable’ or ‘Endangered’ in the European, Swiss and Austrian Red Lists.

Polyommatine blue butterflies reveal unexpected integrity of the W sex chromosome amid extensive chromosome fragmentation

“…1.5% of species were karyotyped (de Vos et al 2020) and few were cytogenetically analyzed in detail due to uniformity of their small metaphase chromosomes which complicated identification of individual chromosomes (de Prins and Saitoh 2003). Recent advances in sequencing technologies provided robust phylogenetic framework and brought genomes to chromosome level, thus offering an unprecedented opportunity to better understand the role of chromosomal changes in lepidopteran speciation (Augustijnen et al 2024, Wright et al 2024).…”

“…The most frequent chromosome number n = 31 is also ancestral (Traut et al 2023, Van’T Hof et al 2013, Wright et al 2024) and extensive karyotype changes are limited only to few groups (de Vos et al 2020, Wright et al 2024). Phylogenetic analyses of diversification indicated a positive association between speciation rates and karyotype evolution in Lepidoptera (Talavera et al 2013a, de Vos et al 2020, Augustijnen et al 2024). Although chromosome fusions are more common than fissions, cladogenetic chromosomal changes associated with speciation events mostly correspond to fissions (de Vos et al 2020, Augustijnen et al 2024).…”

“…Phylogenetic analyses of diversification indicated a positive association between speciation rates and karyotype evolution in Lepidoptera (Talavera et al 2013a, de Vos et al 2020, Augustijnen et al 2024). Although chromosome fusions are more common than fissions, cladogenetic chromosomal changes associated with speciation events mostly correspond to fissions (de Vos et al 2020, Augustijnen et al 2024).…”