1. Soil Science of Temperate and Boreal Ecosystems, Büsgen Institute, Georg‐August‐Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
2. Department of Plant Ecology, Albrecht von Haller Institute of Plant Sciences, Georg‐August‐Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
3. Göttingen Centre for Biodiversity and Ecology, Georg‐August‐Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany
4. present address: Department of Geobotany, Universität Trier, Behringstr. 21, 54296 Trier, Germany