Geoclimatic factors influence the population genetic connectivity of Incarvillea arguta(Bignoniaceae)in the Himalaya-Hengduan Mountains biodiversity hotspot

摘要

Geoclimatic factors related to the uplift of the Himalaya and the Quaternary climatic oscillations influence the population genetic connectivity in the Himalaya-Hengduan Mountains(HHM)biodiversity hotspot.Therefore,to explore the relative roles played by these two factors,we examined the population dynamics and dispersal corridors of Incarvillea arguta(Royle)Royle incorporating ensemble species distribution modelling(SDM).Thirty-seven populations were genotyped using plastid chloroplast DNA and low copy nuclear gene(ncpGS)sequences.Phylogeographic analysis was carried out to reveal the genetic structure and lineage differentiation.Ensemble SDMs were carried out for distributional change in the last glacial maximum,present,and future.Finally,the least cost path method was used to trace out possible dispersal corridors.The haplotypes were divided into four clades with strong geographical structure.The late Miocene origin of I.arguta in the western Himalaya ca.7.92 Ma indicates lineage diversification related to the uplift of the HHM.The variability in habitat connectivity revealed by SDM is due to change in suitability since the Pleistocene.A putative dispersal corridor was detected along the drainage systems and river valleys,with strong support in the eastern Hengduan Mountains group.Our results support the signature of geoclimatic influence on population genetic connectivity of I.arguta in the HHM.We proposed that the major drainage systems might have assisted the rapid dispersal of isolated riverine plant species I.arguta in the HHM.The population genetic connectivity,using the fine-tuned ensemble SDMs,enables scientists and policymakers to develop conservation strategies for the species gene pool in the HHM biodiversity hotspots.