1. Section of Ecology; Department of Biology; University of Turku; Turku Finland
2. Division of Natural Sciences; Kristianstad University; Kristianstad Sweden
3. Department of Wildlife; Fish and Environmental Studies; Swedish University of Agricultural Sciences; Umeå Sweden
4. Finnish Game and Fisheries Research Institute; Joensuu Game and Fisheries Research; Joensuu Finland
5. Department of Forest Sciences; University of Helsinki; Helsinki Finland