1 Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, Ontario K1N 6N5 Canada rsargent@uottawa.ca.
2 Departments of Botany and Zoology, 3529-6270 University Boulevard, University of British Columbia, Vancouver, British Columbia V6T 1Z2 Canada.
3 Department of Geography and Biodiverstiy Research Center, 217-1984 West Mall, University of British Columbia, Vancouver, British Columbia V6T 1Z2 Canada.