Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal’s parks on his bicycle, focusing on observing squirrels. He meticulously documented over 800 grey and black squirrels in nearly 200 green spaces from Mirabel to Saint-Bruno. What initially began as an undergraduate assignment evolved into a personal project driven by his curiosity about how the city’s layout and waterways influence evolution subtly.
Dinh, who is currently pursuing integrative biology at the University of Illinois Urbana-Champaign, relied on his bicycle due to limited public transportation options in suburban areas. He conducted the unique research, making him the sole researcher known to conduct manual squirrel surveys park-by-park across the region.
His findings revealed that around 12% of squirrels in Montreal are black on average, with a higher prevalence of black squirrels observed in northern areas. Regions just north of Laval exhibited up to 40% black squirrels, while the percentages decreased to approximately 20% on the island of Laval, 15% on the island of Montreal, and only 2-3% on the south shore of Montreal. The study attributed this variation primarily to temperature differences, with black squirrels benefiting from their darker coloration’s heat-absorbing properties.
Moreover, the study highlighted the role of forest cover in shaping squirrel populations, as denser tree canopies provide better camouflage for black squirrels against a darker backdrop.
Allison Roth, the study’s senior author and an assistant professor at the University of Missouri, emphasized that the research goes beyond squirrels themselves. Instead, it serves as a model to explore how urban environments drive evolutionary changes. Montreal’s unique environmental features, such as the segmentation by the St. Lawrence River and its tributaries, create fine-scale variations that can lead to genetic and physical adaptations within animal populations.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” sheds light on the intricate interactions between urbanization, local environmental factors, and wildlife adaptations. It challenges the conventional view that human development alone dictates evolutionary changes, highlighting the complex interplay of urban sprawl, temperature fluctuations, tree cover reduction, and natural barriers like rivers.
Dinh reflected on his transformative experience, noting how his perspective on wildlife has evolved. He emphasized the coexistence of urban settings and natural habitats, underscoring the resilience of wildlife amidst human modifications to the environment.
The research, part of a special feature by ecology journals, contributes to the broader understanding of how researchers leverage data and collaboration to address significant ecological questions.