1. Department of Arctic Environment, National Environmental Research Institute, P.O. Box 358, Frederiksborgvej 399, DK-4000 Roskilde, Denmark, Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland, Institute of Public Health, University of Southern Denmark, Winslowparken 17, 5000 Odense, Denmark, Department of Environmental Biology, Università di Siena, Via delle Cerchia 3, 53100 Siena, Italy, Vertebrate Department, Zoological Museum, Universitetsparken 15. DK-2160 Copenhagen Ø,...