1. Department of Biology, University of Wisconsin – Eau Claire, Eau Claire, WI 54702, USA;
2. Research Institute for Agrobiology and Soil Fertility (AB‐DLO), P.O. Box 14, NL‐6700, AA Wageningen, The Netherlands;
3. Unit of Comparative Plant Ecology, Department of Animal and Plant Sciences, Sheffield University, Sheffield S10 2TN, UK;
4. Ecosystem Dynamics, Research School of Biological Sciences, Institute of Advanced Studies, Canberra ACT 0200, Australia;
5. Centre d'Ecologie Fonctionnelle et Evolutive (C.N.R.S.‐U.P.R. 9056), 1919 Route de Mende, F‐34293 Montpellier Cedex 5, France;
6. Department of Botany, Stockholm University, S‐106 91 Stockholm, Sweden;