1. Biodiversity Finnish Environment Institute Natural Environment Centre P.O. Box 413 FI‐90014 Oulu Finland
2. Department of Geosciences and Geography University of Helsinki P.O. Box 64 FI‐00014 Helsinki Finland
3. Department of Geography University of Oulu P.O. Box 3000 FI‐90014 Oulu Finland
4. Finnish Environment Institute Freshwater Centre State of Surface Waters P.O. Box 413 FI‐90014 Oulu Finland
5. Department of Environmental Sciences University of Helsinki P.O. Box 65 FI‐00014 Helsinki Finland
6. Department of Biology University of Oulu Botanical Museum P.O. Box 3000 FI‐90014 Oulu Finland