1 Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6700 AB, Wageningen, The Netherlands. Electronic address: M.Rowe@nioo.knaw.nl.
2 Department of Zoology, Edward Grey Institute, University of Oxford, Oxford OX1 3PS, UK.
3 Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
4 Biosciences, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK.