1. a Department of Biology , University of Tromsø , N‐9037 Tromsø, Norway
2. b Teachers Education , Malmö University , SE‐205 06 Malmö, Sweden
3. c NORUT IT AS , N‐9291 Tromsø, Norway
4. d Department of Physical Geography and Ecosystems Analysis , Lund University , Sölvegatan 12, SE‐223 62 Lund, Sweden
5. e International Institute for Geo‐Information Science and Earth Observation (ITC) , PO Box 6, 7500 AA Enschede, The Netherlands