1. Laboratoire d'Ecologie Alpine; UMR CNRS 5553; University Joseph Fourier; Grenoble 1, BP 53 38041 Grenoble Cedex 9 France
2. Domaine de Charance; Conservatoire Botanique National Alpin; Gap 05000 France
3. Department of Conservation Biology, Vegetation- and Landscape Ecology; Faculty Centre of Biodiversity; Rennweg 14 1030 Vienna
4. Department of Ecology and Evolution; University of Lausanne; 1015 Lausanne Switzerland
5. Institute of Earth Sciences; University of Lausanne; 1015 Lausanne Switzerland
6. Ecologie et Dynamique des Systèmes Anthropisés (EDYSAN, FRE 3498 CNRS); Plant Biodiversity Lab; Jules Verne University of Picardie; 1 Rue des Louvels FR-80037 Amiens Cedex 1 France
7. Ecoinformatics and Biodiversity Group; Department of Bioscience; Aarhus University; Ny Munkegade 114 DK-8000 Aarhus C Denmark
8. Vienna Institute for Nature Conservation and Analyses; Giessergasse 6/7 1090 Vienna Austria
9. Landscape Dynamics; Swiss Federal Research Institute WSL; CH-8903 Birmensdorf Switzerland