Patterns of endemism and comparative phylogeography confirm palaeoenvironmental evidence for Pleistocene refugia in the Eastern Alps

Climatic fluctuations during Quaternary glaciations had a significant influence on the distribution of taxa and on their intraspecific genetic structure. In this paper, we test hypotheses on Pleistocene refugia for mountain plants in the eastern part of the European Alps derived from palaeoenvironmental and geological results, with new data on distributional patterns of 288 vascular plant endemics and molecular phylogeographies of selected species. High numbers of endemics are found in calcareous regions at the southern and the eastern border of the Eastern Alps, which remained unglaciated during the Pleistocene. The distribution of local endemic taxa in general, and of silicicolous taxa in particular, shows a clear relationship with hypothetical glacial refugia in the southern, southeastern, easternmost, and northeastern Alps. Molecular phylogeographic data from several silicicolous alpine species (Androsace alpina, Androsace wulfeniana, Eritrichium nanum, Phyteuma globulariifolium, Ranunculus glacialis, Saponaria pumila) are not completely congruent. However, all genetically defined population groups are in congruence with hypothetical refugia. In general, results from distributions of endemic taxa and data from intraspecific phylogeography are compatible with previously hypothesized refugia suggesting that refugial situations have shaped the current patterns. The combination of patterns of endemism with molecular phylogeographic data provides an efficacious approach to reveal glacial refugia in vascular plants.