1. School of Geography; University of Leeds; Leeds LS2 9JT UK
2. Department of Biogeography and Paleoecology; Adam Mickiewicz University in Poznan; Krygowskiego 10 Poznań 61-680 Poland
3. Department of Environmental Resources and Geohazards; Institute of Geography and Spatial Organisation; Polish Academy of Sciences; Twarda 51/55 Warszawa 00-818 Poland
4. Laboratory of Wetland Ecology and Monitoring; Adam Mickiewicz University in Poznań; Krygowskiego 10 Poznań 61-680 Poland
5. Institute of Plant Sciences and Oeschger Centre for Climate Change Research; University of Bern; Altenbergrain 21 CH-3013 Bern Switzerland