1. Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of OsloPO Box 1066 Blindern, 0316 Oslo, Norway
2. Department of Forestry and Wildlife Management, Hedmark University College2480 Koppang, Norway
3. Division of Biology and Centre for Population Biology, Imperial College LondonSilwood Park, Ascot, Berks SL5 7PY, UK
4. Centre for Environmental Policy, Imperial College LondonExhibition Road, London SW7 2PY, UK