1. Department of Biology; Western University; 1151 Richmond Street London Ontario N6A 5B7 Canada
2. Department of Geography; Indiana University; Bloomington IN 47405 USA
3. Department of Biological Sciences, Center for Ecology and Natural Resources Sustainability; Kent State University; 256 Cunningham Hall Kent OH 44242 USA
4. Nicholas School of the Environment; Duke University; Durham NC 27708 USA