1. Department of Vegetation and Phytodiversity Analysis University of Göttingen Göttingen Germany
2. Department of Biology and Chemistry University of Hildesheim Hildesheim Germany
3. Department of Botany and Zoology Masaryk University Brno Czech Republic
4. Department of General Geobotany Komarov Botanical Institute of the Russian Academy of Science St. Petersburg Russia
5. Wageningen Environmental Research Wageningen University and Research Wageningen The Netherlands
6. Institute for Water and Wetland Research Radboud University Nijmegen The Netherlands