Impact of Quaternary climatic oscillations on phylogeographic patterns of three habitat‐segregated Cerastium taxa endemic to the Dinaric Alps

Abstract

AbstractAimThe Balkan Peninsula has served as source for the colonisation of large parts of Europe after the Pleistocene, but the processes driving the intraspecific diversification within the Balkan Peninsula are much less understood. To fill this gap, we investigated the phylogeography and evolutionary history of three habitat‐segregated Cerastium taxa endemic to the Dinaric Alps and explored whether they responded differently to the Quaternary climatic oscillations in the Balkan Peninsula.LocationEurope, Balkan Peninsula, Dinaric Alps.TaxonCerastium (Caryophyllaceae, angiosperms).MethodsWe combined climatic niche comparisons and species distribution modelling (SDM) on the one hand, with cytological (relative genome size, RGS) and genetic / genomic approaches such as amplified fragment length polymorphism (AFLP) fingerprinting, phylogenetic analyses of nuclear ribosomal internal transcribed spacer (ITS) and plastid (trnT–ndhJ) sequences on the other hand, in order to investigate how the Pleistocene glaciations and the Holocene warming influenced the phylogeographic structure of the studied taxa. SDM was used to reconstruct past, present and future habitat suitability.ResultsDespite nonequivalent climatic niches, we detected climatic niche similarity amongst the three Cerastium taxa. Nonhierarchical K‐means clustering of AFLP data revealed an optimal split into two geographically segregated groups in all three taxa. Genetic divergence between the northwestern and the southeastern populations can be explained by isolation in northern and southern refugia, as suggested by SDM. The ITS and plastid sequences revealed similar, although more complex, patterns of genetic differentiation, and RGS differentiation was mainly geography‐correlated.Main conclusionsDespite the pronounced habitat segregation amongst the studied taxa, their overall phylogeographic structure is similar, suggesting comparable underlying processes and similar responses to the same historical events. However, we anticipate that the three taxa will respond differently to ongoing climate warming.