Eirin Bjørkvoll,^1,2,3 Bård Pedersen,¹ Håkan Hytteborn,¹ Ingibjörg S. Jónsdóttir,^2,4 Rolf Langvatn<sup>2

1</sup>Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
²Department of Arctic Biology, The University Centre in Svalbard, PB. 156, N-9171 Longyearbyen, Norway
³Corresponding author. Present address: Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway eirin.bjorkvoll@bio.ntnu.no
⁴Department of Environmental Sciences, Agricultural University of Iceland, Keldnaholt, IS-112 Reykjavik, Iceland