Grant: Discovery Grants Program - Individual

As the climate continues to warm, we expect plant populations to shift upward in latitude and elevation, and for those at the tail-end of their range to decline. Yet, it is becoming increasingly clear that species are not responding as expected. Our long-term goal in the Northern EDGE Lab is to test how and why climatic and non-climatic factors interact to determine i) plant species' distributional limits and ii) the rate of species' range expansion under climate change. Our approach to progressing the next phase of our long-term goal is to flip our perspective on species' range expansions - or lack thereof. Instead of centering on species we anticipate to shift, we will focus on the communities we expect to be colonized. Through this view, we aim to disentangle the drivers of their ecological inertia - resistance to external change. These communities at the low-latitude or -elevation edge of their range remain stable under ongoing climate change, despite the expectation that they wane as warm-adapted species shift upward. Using field experiments in eastern temperate, boreal, and unforested barrens communities, we will incrementally work towards our long-term goal over the next five years by: 1) Disentangling the driving processes of ecological inertia in plant communities across life stages. We will test the relative effects of predation and competition on temperate and coniferous species that we expect to expand their range into boreal and barrens communities, respectively. 2) Empirically testing changes in the relative effects of inertia-driving processes across space and time. As climate constraints on upper range limits lessen, we predict that biotic interactions will control all range edges. We expect the relative strength of particular biotic drivers of inertia (competition vs predation) to change across the range. We also predict that the strength of dispersal limitations driving inertia will change through time, weakening in high seed production years. 3) Characterizing conditions that lead to rapid change following breaks in ecological inertia. Fire breaks ecological inertia, allowing plant communities to reset. We predict that the length or severity of that break will determine whether the community will self-replace to its pre-fire state, or reassemble to a new state - facilitating range expansion. I aim for this research to continue to occur in our inclusive, equitable EDGE community while actively working towards reconciliation in our research practices. Impacts: We will provide much-need data on the adaptability of Canadian forests to climate change. We will determine how species of economic importance (e.g., black spruce) respond to climate change, and our work will provide data evaluating the resilience of NL forests to climate change. Our 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.