1. School of Biological Sciences University of Portsmouth Portsmouth PO1 2DY UK
2. Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK 99775 USA
3. Norwegian Institute for Nature Research (NINA) Trondheim NO‐7485 Norway
4. Department of Biology, CEES & Evogene University of Oslo PB1016 Oslo 0316 Norway
5. Department of Systematic and Evolutionary Botany University of Zürich Zollikerstrasse 107 Zürich 8008 Switzerland
6. Institute of Biology Centre for Biodiversity Dynamics Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway