Islands as biodiversity arks: the role of insular populations in preserving bat DNA-barcoding diversity

Island ecosystems offer unique opportunities for studying the evolution and ecology of species. Islands may be colonised by propagules whose ecological and evolutionary trajectories will differ from their mainland counterparts, potentially leading to speciation or to the selection and preservation of specific genetic and ecological traits. This study investigates the DNA-barcoding of grey long-eared bats Plecotus austriacus across insular and peninsular regions across its entire range, to unveil the species’ colonization history. We d revealed distinct genetic lineages, since bats from the Iberian Peninsula, Italian Peninsula, Sicily, Elba Island, Great Britain, Sardinia, and Madeira, were all clearly distinguishable within the phylogenetic tree of P. austriacus. Central European samples clustered within a single haplotype. Phylogenetic analyses supported the recognition of a single taxonomic unit for P. austriacus. The evolutionary history of P. austriacus might have been shaped by past range contractions and expansions to and from glacial refugia, with the Iberian Peninsula likely representing the primary source for European populations and their genetic diversity. Island populations, such as those in Sardinia and Madeira, exhibit unique genetic lineages, most likely resulting from isolation after colonization and independent evolutionary trajectories. Elba Island and Great Britain showed unique haplotypes, yet similar to those from the mainland, suggesting a more recent colonization with respect to Madeira and Sardinia. Island populations, along with southern refugial areas, are particularly vulnerable to the impacts of global change, emphasizing the need for conservation strategies addressing the unique needs of these isolated populations.