Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal’s parks on his bicycle in search of squirrels. He meticulously observed and documented over 800 grey and black squirrels in nearly 200 green spaces stretching from Mirabel to Saint-Bruno. What initially began as a student assignment evolved into a personal project to investigate how the city’s layout and meandering waterways influence evolutionary patterns.
Expressing his newfound admiration for squirrels, Dinh remarked, “I fell in love with them after spending considerable time observing and contemplating their existence. Often overlooked as mere pests, squirrels are indeed a part of the city’s wildlife fabric.” Due to limited public transit options in suburban regions and without a car, Dinh relied on his bike to conduct comprehensive squirrel surveys across the area’s parks, making him the sole researcher known to have conducted manual park-by-park squirrel assessments in the region.
Dinh’s research revealed that approximately 12% of Montreal’s squirrel population are black, with higher concentrations of black squirrels found as he ventured further north. In areas just beyond Laval, he observed up to 40% black squirrels, whereas on Laval Island, around 20% were black. On Montreal Island, the percentage stood at 15%, and it dropped to 2-3% on the south shore of Montreal. The study attributed this variation primarily to temperature differences, with the cooler northern regions favoring black squirrels due to their superior heat-absorbing black coloration.
Additionally, the study highlighted the impact of forest cover on squirrel coat coloration, noting that denser tree canopies provide a darker backdrop where black squirrels are better camouflaged. Senior author of the study, Allison Roth, emphasized that the research focuses on using squirrels as a model to explore how urban environments drive evolutionary changes rather than solely studying squirrels themselves. She underscored the significance of Montreal’s diverse neighborhoods and distinct environmental features, such as the St. Lawrence River and its tributaries, in shaping fine-scale genetic and physical adaptations in animal populations.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” marks a shift from previous city-versus-countryside comparisons to a neighborhood-by-neighborhood analysis of wildlife changes. Contrary to earlier beliefs that human development primarily influences these changes, the study unveils the multifaceted role of urbanization in altering local temperatures, reducing tree cover, and creating natural barriers like riverways.
As the research contributes to a special feature by five ecology journals examining collaborative efforts to address significant ecological questions, Dinh reflected on how his perspective on wildlife has transformed. He emphasized the interconnectedness of urban and natural environments, highlighting that wildlife will persist despite human modifications to their habitats.