Phylogeography of the high alpine cushion plant Androsace alpina (Primulaceae) in the European Alps

Recent studies elucidating the glacial history of alpine plants have yielded controversial results. While some have favoured glacial survival on mountain tops above the glaciers (nunataks), others did not find support for this hypothesis. Furthermore, all of the published phylogeographic patterns are strikingly different. In order to provide more data for a future comparative phylogeographical approach, we investigated 53 populations of the high alpine cushion plant Androsace alpina (Primulaceae), endemic to the European Alps, using amplified fragment length polymorphism (AFLP). While Principal Co-ordinate Analysis (PCoA) of populations revealed four genetically-defined phylogeographical groups corresponding to geographic regions, Neighbour joining analysis (NJ) separated only three groups. Mantel tests were used to assess the goodness-of-fit between the grouping in PCoA and the genetic similarity matrix, and these showed high similarity between the two eastern phylogeographical groups. This, together with other lines of evidence, is interpreted as an indication for colonization of the eastern part of the distributional range of A. alpina from westerly adjacent populations. The phylogeographical groups can all be related to potential refugia for alpine plants, based on geological and palaeoclimatological data. However, due to the comparatively weak phylogeographical structure, our data do not allow us to rule out glacial survival on nunataks in central parts of the Pleistocene ice shield.