Combining distribution modelling and phylogeography to understand present, past and future of an endangered spider

Background Understanding how endangered species respond to climatic changes is fundamental for their con- servation. Due to its restricted geographic range, its sensitivity to the ongoing global warming and its continuing decline, the Southwestern-Alpine endemic wolf spider Vesubia jugorum is currently classified as Endangered in the IUCN Red List. Here, we combined species distribution modelling (SDM) and phylogeographic inference to describe the present, the past and the future of this species in light of the mtDNA genetic structure of extant populations. Results Phylogenetic and network analyses show a high level of genetic differentiation and a strong genetic struc- ture of the populations, likely explicable by a long history of isolation and survival in separate refugia. The SDM projection into past climatic conditions supports these results by showing a smaller distribution range compared to present, mostly restricted to the Maritime and Ligurian Alps, which possibly served as the main refugium for the species.Future forecast shows a significant shift in the bioclimatic range towards higher altitudes and latitudes, with a dras tic decrease of habitat suitability in the central and south-eastern parts of the range, with consequent general loss of haplotype diversity. Conclusion SDM and phylogeographic inference support the hypothesis that the current distribution and the genetic structure of the extant populations mirror the survival of Vesubia jugorum across repeated glacial and interglacial phases in situ, in line with the ‘long-term stability hypothesis’. Future predictions show a significant shift in the bioclimatic range that V. jugorum will be likely unable to track, with profound impact on its long-term survival and its genetic diversity. Our considerations have implication for conservation genetics, highlighting the pivotal role of the transboundary protected areas of the SW-Alps in promoting conservation efforts for this species.