1. Botanical Institute, University of Basel, Hebelstrasse 1, CH‐4056 Basel, Switzerland
2. Netherlands Institute of Ecology (NIOO‐KNAW), Centre for Terrestrial Ecology, Department of Terrestrial Microbial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands
3. Ecological Farming Systems Group, Agroscope Reckenholz‐Tänikon, Research Station ART, Reckenholzstrasse 191, CH‐8046 Zürich, Switzerland
4. Institute of Ecological Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands