Francis Quang-Hai Dinh’s initial summer at McGill University involved traversing Montreal’s parks on his bicycle in a quest to locate squirrels. He journeyed to nearly 200 green spaces spanning from Mirabel to Saint-Bruno, meticulously observing and documenting over 800 grey and black squirrels. What began as a college assignment soon evolved into a personal endeavor to unravel how the city’s structure and meandering watercourses are subtly influencing evolution.
“I developed a fondness for them after spending considerable time observing and contemplating them,” mentioned Dinh. “Squirrels are often disregarded as mere pests, but in reality, they are part of the wildlife.”
Lacking a car and facing limited public transportation options in suburban regions, Dinh heavily relied on his bicycle to reach as many locations as possible, making him the sole researcher known to manually survey squirrels park-by-park across the area.
In his findings, Dinh noted that around 12 percent of squirrels in Montreal exhibited black fur. Interestingly, as he ventured further north, the prevalence of black squirrels increased significantly. In regions just north of Laval, up to 40 percent of squirrels sported black coats. On Laval Island, this figure stood at about 20 percent, while on Montreal Island, it was approximately 15 percent. The percentage dwindled to merely two or three percent on the southern shore of Montreal. Dinh, now pursuing integrative biology at the University of Illinois Urbana-Champaign, attributed these variations to temperature differences, with cooler climates up north favoring the presence of black squirrels due to their superior heat absorption capabilities.
Additionally, forest cover played a crucial role in this phenomenon. Denser tree canopies created a darker environment where black squirrels could blend in more effectively.
The study’s primary investigator, Allison Roth, an assistant professor at the University of Missouri and former postdoctoral fellow at McGill, emphasized that the research extended beyond squirrels themselves. Instead, it aimed to utilize them as a model to examine how urban settings stimulate evolutionary shifts.
Roth highlighted the distinct nature of cities, with varying neighborhoods, tree cover levels, and defining features like Montreal’s water bodies, contributing to nuanced environmental differences that can prompt genetic and physical adaptations within the same animal population.
The study, entitled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” delves into these intricate urban dynamics, contrasting previous broader city vs. countryside comparisons by focusing on wildlife shifts at the neighborhood level. It underscores that while urban expansion alters local climates and vegetation, natural barriers like rivers also play a pivotal role in shaping wildlife evolution.
The research findings, part of a special feature by several ecology journals exploring collaborative efforts to address significant ecological inquiries, shed light on the intricate interplay between urbanization, environmental factors, and wildlife adaptations.
Reflecting on his experiences, Dinh expressed a newfound perspective on wildlife interactions, emphasizing the coexistence of urban development and natural habitats. He remarked, “Despite our alterations, wildlife will persist and thrive in our shared spaces.”
The study by Dinh and his team represents a significant contribution to understanding the intricate ecological dynamics shaping urban wildlife populations.
