Non-climatic controls on tree species distributions under climate change

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The long-term goal of my research program is to investigate tree species response to climate change as expressed by the expansion, or lack thereof, of their geographic distributions, with a particular focus on the role non-climatic factors play in that response. Predicting the distribution of future species under climate change is one of the greatest scientific challenges we currently face. Usually, scientists try to address this challenge by looking at the direct links between climate and species distributions; however, the effects of non-climatic factors, such as soil conditions or species interactions, can sometimes override climate effects, requiring field experimentation to tease out their individual contributions. My recent research has shown that non-climatic factors, such as seed predation and soil organisms, have an overriding effect on tree species distribution limits under climate change, which can change across life stages. I've also shown that landscape-scale disturbances, such as fires, can spur a species' distributional response to climate change. Over the next five years, my short-term goal is to further advance our understanding of non-climatic controls on species distributions by conducting explicit experiments addressing:***1) The relative importance of both biological and environmental interactions on species recruitment at their range/distribution limit during the early part of their lifespan;***2) The mechanisms underlying how environmental disturbances can spur a species to expand its range/distribution; and ****3) Whether these mechanisms driving species range limits can be generalized to multiple spatial scales and stages of life.***This research will use boreal and temperate tree populations, native to Eastern Canada, at their distributional/range limit as model systems. Experiments will be conducted within, at the edge, and beyond a species range limit, and will incorporate multiple life stages. Understanding how a species will respond to climate change requires an understanding of its climatic and non-climatic drivers from germination to reproductive maturity, and how climate-induced changes to disturbance patterns (such as the increase in forest fires) will influence those responses. This research will provide much-need data on where, and under what circumstances, tree range expansion can occur, aiding in our ability to adapt to or mitigate future conditions, which could have potential economic repercussions.**