1. Forest & Nature Lab Ghent University Geraardsbergsesteenweg 267 BE‐9090 Gontrode‐Melle Belgium
2. Forest Ecology and Conservation Group Department of Plant Sciences University of Cambridge Downing Street Cambridge CB2 3EA UK
3. Department of Biology Norwegian University of Science and Technology NO‐7491 Trondheim Norway
4. Vegetation Ecology and Conservation Biology Institute of Ecology FB2 University of Bremen Leobener Str. DE‐28359 Bremen Germany
5. Ecologie et Dynamique des Systèmes Anthropisés (EDYSAN, FRE CNRS 3498) Université de Picardie Jules Verne 1 rue des Louvels FR‐80037 Amiens Cedex France
6. Division of Plant Conservation and Population Biology K. U. Leuven Kasteelpark Arenberg 31 BE‐3001 Leuven Belgium
7. Department of Ecology, Environment and Plant Sciences Stockholm University SE‐106 91 Stockholm Sweden
8. Division Forest, Nature and Landscape K.U.Leuven Celestijnenlaan 200E BE‐3001 Leuven Belgium
9. Department of Physical Geography and Quaternary Geology Stockholm University SE‐106 91 Stockholm Sweden