1. Redpath Museum; McGill University; 859 Sherbrooke Street West; Montreal; Quebec; H3A 2K6; Canada
2. Nature Conservation and Plant Ecology Group; Wageningen University; PO Box 47; 6700 AA; Wageningen; The Netherlands
3. Institute of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190; CH-8057; Zurich; Switzerland
4. US Geological Survey; 700 Cajundome Blvd; Lafayette; LA; 70506; USA
5. USDA Agricultural Research Service; Grassland, Soil and Water Research Laboratory; 808 East Blackland Road; Temple; Texas; 76502; USA
6. UFZ, Helmholtz Centre for Environmental Research; Department of Community Ecology; Theodor-Lieser-Strasse 4; 06120; Halle; Germany
7. Department of Ecology; Evolution and Behavior; University of Minnesota; St. Paul; Minnesota; 55108; USA
8. Institute of Biology; University of Leipzig; Johannisallee 21-23; 04103; Leipzig; Germany
9. Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames; Iowa; 50011; USA