1. WSL Institute for Snow and Avalanche Research SLF; CH-7260 Davos Switzerland
2. Institute of Botany; University of Basel; CH-4056 Basel Switzerland
3. Evolutionary Biology Centre; University of Uppsala; 752 36 Uppsala Sweden
4. Department of Biology; University of Konstanz; 78457 Konstanz Germany
5. Institute of Evolution & Ecology; University of Tübingen; D-72076 Tübingen Germany