1. Department of Ecology and Evolution; University of Fribourg; Fribourg Switzerland
2. Swiss Federal Research Institute WSL; Birmensdorf Switzerland
3. Landscape Ecology; Institute of Terrestrial Ecosystems; ETH Zürich; Zürich Switzerland
4. Institute of Botany; Ilia State University; Tbilisi Georgia
5. Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
6. Institute of Earth Surface Dynamics; University of Lausanne; Lausanne Switzerland