1. Institute of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, 100871 Beijing, China
2. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
3. Department of Environmental Sciences, Zoology, University of Basel, CH-4051 Basel, Switzerland
4. Tvärminne Zoological Station, University of Helsinki, 10900 Hanko, Finland
5. Department of Evolutionary Biology and Environmental Studies, University of Zurich, CH-8057 Zürich, Switzerland
6. Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland