1. Forest & Nature Lab; Ghent University; Geraardsbergsesteenweg 267 BE-9090 Gontrode-Melle Belgium
2. Department of Plant Production; Ghent University; Proefhoevestraat 22 BE-9090 Melle Belgium
3. Southern Swedish Forest Research Centre; Swedish University of Agricultural Sciences; Box 49 SE-230 53 Alnarp Sweden
4. EDYSAN (FRE 3498 CNRS-UPJV); Université de Picardie Jules Verne; 1 rue des Louvels FR-80037 Amiens Cedex France
5. Department of Biology; Norwegian University of Science and Technology; NO-7491 Trondheim Norway
6. IFM - Biology; Linköping University; SE-581 83 Linköping Sweden
7. Forest, Nature & Landscape; K.U. Leuven; Celestijnenlaan 200E BE-3001 Leuven Belgium
8. Vegetation Ecology & Conservation Biology, FB2; University of Bremen; Leobener Str. DE-28359 Bremen Germany
9. Department of Ecology, Faculty of Biology & Environmental Protection; University of Silesia; ul. Bankowa 9 PL-40-007 Katowice Poland
10. Department of Physical Geography; Stockholm University; SE-106 91 Stockholm Sweden
11. Plant Conservation & Population Biology; K.U. Leuven; Kasteelpark Arenberg 31, Box 2435 BE-3001 Leuven Belgium
12. Institute of Land Use Systems; Leibniz-ZALF; Eberswalder Strasse 84 DE-15374 Müncheberg Germany