1. Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA;
2. Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, British Columbia, Canada
3. Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
4. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
5. The Arnold Arboretum, Harvard University, Boston, Massachusetts, USA