1. Montana Conservation Science Institute 5200 Upper Miller Creek Road Missoula Montana 59803 USA
2. Department of Biological Sciences University of Idaho Moscow Idaho 83844 USA
3. Department of Biological Sciences University of Alberta Edmonton Alberta T6G 2E9 Canada
4. Centre for Ecology and Conservation University of Exeter Penryn Cornwall TR10 9FE UK
5. Faculté des Sciences Université de Sherbrooke Sherbrooke Québec J1K 2R1 Canada