Combining palaeodistribution modelling and phylogeographical approaches for identifying glacial refugia in Alpine Primula

Abstract

AbstractAimWe investigated the late Quaternary history of two closely related and partly sympatric species of Primula from the south‐western European Alps, P. marginata Curtis and P. latifolia Lapeyr., by combining phylogeographical and palaeodistribution modelling approaches. In particular, we were interested in whether the two approaches were congruent and identified the same glacial refugia.LocationSouth‐western European Alps.MethodsFor the phylogeographical analysis we included 352 individuals from 28 populations of P. marginata and 172 individuals from 15 populations of P. latifolia and used amplified fragment length polymorphisms (AFLPs). For palaeodistribution modelling, species distribution models (SDMs) were based on extant species occurrences and then projected to climate models (CCSM, MIROC) of the Last Glacial Maximum (LGM), c. 21 ka.ResultsThe locations of the modelled LGM refugia were supported by various indices of genetic variation. The refugia of the two species were largely geographically isolated, overlapping only 6–11% of the species' total LGM distribution. This overlap decreased when the position of the glacial ice sheet and the differential elevational and edaphic distributions of the two species were considered.Main conclusionsThe combination of phylogeography and palaeodistribution modelling proved useful in locating putative glacial refugia of the two alpine species of Primula. The phylogeographical data allowed us to identify those parts of the modelled LGM refugial area that were likely source areas for recolonization. The use of SDMs predicted LGM refugial areas substantially larger and geographically more divergent than could have been predicted by phylogeographical data alone.