Francis Quang-Hai Dinh embarked on a unique summer project during his first year 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 spanning from Mirabel to Saint-Bruno. What began as a simple undergraduate assignment evolved into a personal mission to investigate how the city’s geography and water systems influence evolution.
Dinh, now pursuing integrative biology at the University of Illinois Urbana-Champaign, became the sole researcher to conduct manual squirrel surveys park-by-park in the region due to limited transportation options in suburban areas.
His findings revealed that the prevalence of black squirrels increases as one moves further north from Montreal. In areas just north of Laval, up to 40% of the squirrel population exhibited black coats, while the percentage dropped to 15% on the island of Montreal and further decreased to 2-3% on the south shore.
The study attributed this phenomenon to several factors, with temperature playing a key role. The cooler climates in northern regions favor black squirrels due to their better heat-absorbing black coloration. Additionally, the density of forest cover influences the prevalence of black squirrels as they are better camouflaged against darker backdrops.
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 understand how urban environments drive evolutionary changes. Montreal’s unique landscape, segmented by waterways like the St. Lawrence River, creates distinct environmental variations that can lead to genetic and physical adaptations within the squirrel population.
While most studies on urban wildlife evolution compare cities to rural areas, this research delves into neighborhood-specific changes. It challenges the notion that human development is the sole driver of such transformations, highlighting how urban sprawl, temperature variations, and natural barriers like rivers collectively shape wildlife evolution.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” underscores the importance of local vegetation structure and winter microclimate in influencing melanism, with urbanization indirectly impacting these factors. The research forms part of a special feature by ecology journals exploring collaborative approaches to address ecological questions.
Dinh reflected on his transformed perspective towards wildlife, acknowledging the coexistence of nature and urban settings. He emphasized that wildlife persists despite human modifications, emphasizing the interconnectedness of city life and natural habitats.