1. Dept of Biological and Environmental Science, PO Box 35, FI‐40015 University of Jyväskylä Finland
2. Dept of Ecology and Evolutionary Biology, Univ. of Arizona Tucson AZ USA
3. Dept of Ecology and Evolutionary Biology, Univ. of Michigan Ann Arbor MI USA
4. Center for the Study of Complex Systems, Univ. of Michigan Ann Arbor MI USA