1. Department of Biological Sciences University of Alberta Edmonton Alberta T6G2E9 Canada
2. School of Environmental and Rural Science University of New England Armidale New South Wales 2351 Australia
3. Biological Control and Spatial Ecology Lab (LUBIES) Université Libre de Bruxelles Brussels Belgium
4. Natural Resources and Environmental Studies Institute University of Northern British Columbia Prince George British Columbia V2N 4Z9 Canada