1. Long-term Ecology Laboratory, Oxford University Centre for the EnvironmentSouth Parks Road, Oxford OX1 3QY, UK
2. Department of Biodiversity and Evolutionary Biology, National Museum of Natural SciencesC/José Gutiérrez Abascal 2, Madrid 28006, Spain
3. Department of Earth Sciences, PalaeobiologyVillavägen 16, 752 36 Uppsala, Sweden
4. Visiting Professor at School of Geography, Oxford University Centre for the EnvironmentSouth Parks Road, Oxford OX1 3QY, UK