Research

My research uses genomics to understand rapid evolution in response to global environmental change. Climate change is one of the leading contributors to the biodiversity crisis. Populations that are threatened by climate change have four options: move, acclimate, adapt, or go extinct. These options shrink for species that are at the edge of their range or that are limited in their ability to plastically respond to rapid environmental change. Whether populations can adapt in response to climate change will depend on their genetic potential for adaptation, their evolutionary history, and the strength of selection imposed by climate change. Determining how and when populations adapt is vital for understanding the ecological resilience of species to climate change and mitigating future losses of biodiversity.

Conservation Genetics of Polar Bears

The Arctic is the fastest warming region on Earth. By 2035, the Arctic Ocean is predicted to become entirely ice-free in the summer, threatening the survival of ice-adapted species. My research focuses primarily on polar bears, a flagship species that often represents a public face for climate action. Using a combination of whole-genome sequencing, bioinformatics, and climate modelling, my research seeks to map the genomic architecture of recent evolution in polar bears by examining adaptive capacity, recent demographic changes, and predicted effects of continued warming. My aim is to use genetic information to help guide conservation strategies for preserving biodiversity in the Canadian Arctic.

Adaptation and evolution in the Arctic

Despite extensive knowledge of the ecological consequences of climate change, we know much less about how climate warming shapes patterns of evolution in polar bears. My review of climate-linked genetics and evolution in polar bears found little evidence for recent adaptation in the species, despite clear differences in genetic variation, gene flow, and plasticity across their range. Using genetic offsets to evaluate the genetic suitability of polar bears to future environments under warming, I found that selection pressure on polar bears differs depending on their location in the Arctic and the abundance of the subpopulation. Polar bears in the high Arctic (>68 °N) had the lowest genetic diversity and the largest genetic mismatch to warming compared to other regions of the Arctic, putting them at risk of maladaptation to climate change. Opportunities for genetic rescue via introgression are also limited, as there have been few cases of hybridization with grizzly bears in the recent past. Together, these results point to limited potential for adaptive responses to warming in polar bears. However, there may be specific genes under selection that could contribute to adaptation, which still need to be explored.

Demographic history of polar bears

The rate of environmental change in the Arctic is occurring at an unprecedented pace due to climate change. Populations that have experienced recent demographic declines may be particularly vulnerable to the impacts of climate change and may exhibit small effective population sizes and increased inbreeding depression and genomic load. Accurate assessments of population viability require tracking recent demographic history, estimating Ne and inbreeding rates, and tying these measures into estimates of fitness, survival, and adaptation. Given the rapid loss of sea ice in the Arctic, population viability assessments would benefit from considering evolutionary processes, which may identify avenues for conservation interventions that promote fitness and facilitate adaptation to the changing environment. Stay tuned for more results on this project.

Urban Evolutionary Ecology

My PhD research explored general patterns of ecology and evolution in urban environments. Cities are undergoing some of the most rapid environmental change of any ecosystem. Studies on urban ecology and evolution are growing in number, however there remain many unanswered questions. Together with collaborators, I created a roadmap for future research in the field. We identified the big, unanswered questions in the field, and highlight areas for better integration into urban management, conservation, and education. This work has helped generate research in the field, including the creation of Urban Eco Evo Net, a research network to advance the study and understanding of eco-evolutionary dynamics in an urban planet

I am currently working on a population genetics project looked at the effects of urbanization on adaptive and neutral genetic variation of jewelweed (Impatiens capensis) across multiple cities. Jewelweed is a native wildflower that can be found in many cities in eastern North America, but the species is entirely reliant on parks and urban greenspace for survival. We used genotype-by-sequencing to evaluate genetic variation, contemporary demographic history, and local adaptation across 10 cities in Ontario, Canada. Urbanization and city size shaped the amount of genetic diversity present at sites and contributed to fine-scale spatial genetic structure and local adaptation. Despite high levels of genetic diversity, we identified a signal of repeated genetic bottlenecks across all cities that corresponded to the timing of rapid urban expansion in the region. Our results point to the role that gene flow can play in maintaining resilience to urbanization and suggest that prioritizing greenspace conservation is critical for maintaining urban biodiversity. You can read more about this work here.

In addition to this research, I have studied patterns of non-adaptive evolution across species, to better understand the effects of urbanization on genetic diversity and differentiation. I have also been involved in several opinion pieces calling for the better integration of human societal factors into urban ecology and evolution.

Urban species interactions

While urbanization has been demonstrated to influence the ecology and evolution of species, less is known about how urbanization affects interactions among species. Species interactions play an important role in shaping ecosystems because they mediate species abundances, distributions, and habitat use patterns. Consequently, understanding how urbanization influences species interactions is critically important as the number and size of cities continues to grow.

My PhD research investigated how urbanization influences the ecology and interactions of plants with their pollinators and herbivores. I measured the effects of urbanization on plant-pollinator and plant-herbivore interactions, and found that urbanization alters interactions between Brassica rapa and its pollinators, leading to altered patterns of pollen dispersal and reproductive success in cities].Similarly, my results demonstrated that even small human settlements lead to increased seed predation rates and modified natural selection in Tribulus cistoides.