Recent immigrants or ancient witnesses of recurrent climate change? The fate of rare arctic plants in the Alps revisited

The Alps harbor a large number of plants that are predominantly distributed in the Arctic. Some of them are extremely rare in the Alps. Most of the rare arctic-alpine plants are not occurring in peripheral parts of the Alps that remained unglaciated during the last glaciation (18.000 BP), but are restricted to the highest, formerly most extensively glaciated parts of the Alps. Many authors explained the origin of Alpine populations of arctic-alpine plants by migration through the lowlands during earlier cold periods of the Quaternary and survival on mountain tops within the ice-shield during the last glacial mximum. Alternatively, the rare arctic-alpine plants could be young immigrants that reached the Alps after the last glaciation and the restriction to the highest and most central parts of the Alps might have ecological causes. The main goal of the proposed research is to unravel the immigration history of five rare arctic-alpine model taxa in the Alps applying molecular methods (fingerprinting and sequencing). The main question addressed is whether the rare arctic-alpine plants in the Alps are old glacial survivors or young immigrants. If they are young immigrants I will focus (a) on the source areas for the colonisation of the Alps and (b) on the mode of origin of the Alpine populations (single vs. multiple introductions). If rare arctic-alpine plants are old glacial survivors, I aim to unravel their phylogeographical structure in the Alps. As some of the rare arctic-alpine plants in the Alps are critically endangered, my results could also contribute to select genetically most divergent or variable populations as targets for conservation strategies. The proposed study will be an important contribution to the knowledge of the origin of the arctic-alpine element in the Alps in particular and of processes during plant migrations in general.