Our Projects.
Research in the Northern EDGE Lab is focused on how species' distributions are actually responding to global change. We are particularly interested in indirect climatic effects (like climate-induced changes to disturbance regimes) and non-climatic effects (like substrate limitations) on species' range limits. What we find really exciting are all of the unexpected constraints on range expansions caused by species' interactions. While these themes are the main focus of the lab, we are interested in a diversity of research topics related to biogeography, plant ecology, arctic ecosystems...have an idea? Get in touch!
G-TREE: Global Treeline Range Expansion Experiment
G-TREE is a global research network composed of >40 arctic and alpine researchers from around the world. The idea is to implement an inexpensive, effective field experiment at many treelines around the world to test the generality of mechanisms driving treeline dynamics.
This summer, our field experiment will be established at numerous sites across Canada, France, Norway, Spain, the United States, and Venezuela. Other sites are being developed in Russia, Australia, and Sweden, to name a few. We are always looking for new study regions and researchers to participate. Please contact Carissa or visit treelineresearch.com if you are interested.
Non-climatic constraints on species' range expansions
Species’ range limits are expected to shift northward and upward in elevation with increased temperatures as climatic constraints on species’ establishment and survival lessen. However, little attention has been paid to non-climatic factors influencing range expansion. Mountains in northeastern North America often exhibit a transition with increasing elevation from sugar maple-dominated deciduous forests characteristic of milder climates to coniferous forests distinctive to northern and subarctic ecosystems. With increasing summer temperatures and growing season length, one might expect an upward shift in the elevational range limit of sugar maple. We know that climate is not the only constraint on species' distributions in alpine environments, however. Along with Dr. Mark Vellend at l'Université de Sherbrooke, we are investigating the climatic and edaphic factors that limit the distribution of species in mountain ecosystems, and how those factors may interact to drive future species' distributions.
Effects of climate-induced shifts in disturbance regimes
Climate change is expected to alter patterns of disturbance, which in turn may drive future ecosystem change. This interaction may be particularly important in sub-arctic regions due to rapid climate change and frequent fire. With increased temperatures in northern ecosystems, there is an assumption that typically southern species will shift their distributions northwards. In the northwestern boreal forest, however, the bottleneck to forest establishment is recruitment, which is strongly mediated by reproductive output and disturbance effects. This research, in collaboration with Dr. Jill Johnstone at the University of Saskatchewan and PPS Arctic, focuses on how indirect climate effects caused by changes to disturbance regimes may initiate vegetation shifts in sub-arctic forest dominated by black spruce. Specifically, we are investigating what happens when disturbance regimes become misaligned with reproductive cycles.