1. GIS-centre, Lund University, Sdlvegatan 12, SE-223 62 Lund, Sweden;
2. Department of Ecology, Evolution and Behaviour, University of Minnesota, 1987 Upper Buford Circle, St Paul, MN 55108-6097, USA
3. Department of Biology and Environmental Sciences, Kalmar University, SE-39182 Kalmar, Sweden
4. GIS-centre, Lund University, Sdlvegatan 12, SE-223 62 Lund, Sweden