1. Laboratory of Ecological Systems; EPFL; Station 2 CH-1015 Lausanne Switzerland
2. Department of Botany and Zoology; Masaryk University; Kotlářská 2 CZ-61137 Brno Czech Republic
3. Department of Vegetation Ecology; Institute of Botany; Academy of Sciences of the Czech Republic; Lidická 25/27 CZ 657 20 Brno Czech Republic