Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal’s parks on his bicycle, observing and documenting over 800 grey and black squirrels across nearly 200 green spaces from Mirabel to Saint-Bruno. What began as a simple undergraduate task evolved into a passionate endeavor to understand how the city’s layout and waterways influence evolution.
Dinh, who is now pursuing integrative biology at the University of Illinois Urbana-Champaign, relied on his bicycle for transportation due to a lack of car access and limited public transit options in suburban areas. This made him the sole researcher known to conduct manual squirrel surveys park-by-park throughout the region.
His research revealed that approximately 12% of squirrels in Montreal are black, with higher concentrations of black squirrels as he moved further north. The study identified temperature as a significant factor, with cooler climates in northern regions favoring black squirrels due to their better heat-absorbing black coloration.
Moreover, forest cover played a role in squirrel coat color variation, as denser tree canopies provided a darker backdrop that enhanced the camouflage of black squirrels. The study, led by Allison Roth, an assistant professor at the University of Missouri, and former postdoctoral fellow at McGill, aimed to use squirrels as a model to explore how urban environments drive evolutionary changes.
Roth highlighted the unique environmental variations in cities like Montreal, shaped by factors such as diverse neighborhoods, varying tree cover levels, and natural boundaries like the St. Lawrence River. These factors create fine-scale differences that lead to diverse genetic and physical adaptations within the same animal population.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” stands out for its focus on changes in wildlife on a neighborhood-by-neighborhood basis, rather than comparing cities as a whole to rural areas. It challenges the notion that human development alone drives these changes, emphasizing the intricate interplay of urban sprawl, local temperature shifts, tree cover reduction, and natural barriers like riverways.
The research, part of a special feature by ecology journals, showcases how data and collaboration advance understanding of significant ecological questions. Dinh noted that his perspective on wildlife has shifted, recognizing the coexistence of nature and urban environments, where wildlife adapts and thrives despite human modifications.