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 across nearly 200 green spaces stretching from Mirabel to Saint-Bruno. What began as a simple undergraduate task evolved into a passionate endeavor to unravel how the city’s layout and meandering water bodies influence evolution.
Dinh, who is currently pursuing integrative biology at the University of Illinois Urbana-Champaign, conducted a unique survey, traveling park-by-park on his bicycle due to limited public transit access in suburban areas. His research revealed that the prevalence of black squirrels increases as one moves further north. In regions just beyond Laval, up to 40% of squirrels displayed black coats, compared to around 20% on Laval Island, 15% on Montreal Island, and only 2-3% on the south shore of Montreal.
The study attributed this phenomenon primarily to temperature variations. Warmer climates in the south favor grey squirrels, while the cooler northern regions provide an advantage to black squirrels due to their better heat absorption capabilities. Additionally, the density of forest cover plays a crucial role, as black squirrels blend more effectively in areas with denser tree canopies.
Allison Roth, the study’s senior author and an assistant professor at the University of Missouri, emphasized that the research focuses on using squirrels as a model to examine how urban environments shape evolutionary changes. Montreal’s unique urban landscape, characterized by diverse neighborhoods, varying tree coverage, and natural boundaries like waterways, creates micro-environmental differences that drive genetic and physical adaptations in wildlife populations.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” breaks new ground by analyzing wildlife evolution on a neighborhood-specific level rather than comparing cities as a whole to rural areas. It challenges the conventional belief that human development alone drives such changes, highlighting the intricate interplay between urbanization, local temperature variations, vegetation structure, and natural barriers.
Dinh reflected on his transformed perspective towards wildlife, noting the coexistence of urban development and nature. He emphasized the resilience of wildlife in adapting to human modifications, underscoring the interconnectedness of city life and natural ecosystems.
