2 Departamento de Ecologia, Universidade de São Paulo, CEP 05508-090, São Paulo, SP, Brazil;
3 Department of Engineering and Mathematics, University of Bristol, Bristol BS8 1UB, United Kingdom; Max Planck Institute for the Dynamics of Complex Systems, D-01187 Dresden, Germany;
4 Departments of Anthropology and Biological Sciences, Dartmouth College, Hanover, NH 03755; and.
5 Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064.