1. Plant Ecology Institut für Biologie Freie Universität Berlin D‐14195 Berlin Germany
2. Laboratory of Ecology and Environmental Protection Faculty of Agriculture Aristotle University of Thessaloniki 541 24 Thessaloniki Greece
3. State Key Laboratory of Urban and Regional Ecology Research Center for Eco‐Environmental Sciences Chinese Academy of Sciences Beijing 100091 China
4. University of Chinese Academy of Sciences PO Box 2871 Beijing China
5. Department of Biology University of York York YO10 5DD UK
6. Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB) D‐14195, Berlin Germany
7. Department of Soil and Water Conservation CSIC‐Centro de Edafología y Biología Aplicada del Segura PO Box 164, Campus de Espinardo 30100 Murcia Spain
8. School of Earth and Environmental Sciences The University of Manchester Manchester M13 9PT UK