1. Department of Ecological Science; Faculty of Earth and Life Sciences; VU University Amsterdam; De Boelelaan 1085; 1081; HV Amsterdam; The Netherlands
2. Institute of Botany; Czech Academy of Sciences; Dukelská 135; 379 82; Třeboň; Czech Republic
3. Swiss Federal Research Institute WSL; Community Ecology; Via Belsoggiorno 22; 6500; Bellinzona; Switzerland