1. Global Ecology Unit CREAF‐CSIC‐UAB CSIC Cerdanyola del vallès Catalonia 08193 Spain
2. CREAF Cerdanyola del vallès Catalonia 08193 Spain
3. Service of Nuclear Magnetic Resonance and Chemistry Department Faculty of Sciences and Biosciences Universitat Autònoma de Barcelona Bellaterra Catalonia 08913 Spain
4. Global Change Research Centre Academy of Sciences of the Czech Republic Belidla 4a CZ‐60300 Brno Czech Republic
5. Disturbance Ecology and Vegetation Dynamics University of Bayreuth Bayreuth D‐95440 Germany
6. Department of Biogeography University of Bayreuth Bayreuth D‐95440 Germany