Urban landscapes are a complex combination of natural, physical, social, and built elements. Each element of a city can benefit urban residents, with the benefits that we receive from natural elements often labelled as “ecosystem services”. The capacity for ecosystem services in a particular neighbourhood or city is determined by many different drivers, such as tree diversity. We hypothesize that across cities, there are some common drivers, i.e., cross-city drivers, that influence the ecosystem service capacity provided by urban trees in a consistent way. Determining the cross-city drivers of ecosystem services could allow urban planners and other stakeholders to understand the ecology and plan effectively before ever planting a tree, thus contributing to an increased ability to plan healthy and equitable cities. Our research specifically asks: What are the cross-city drivers of regulatory ecosystem service capacity across Canada? We use publicly available data to test ecosystem services and their drivers in seven cities that span a longitudinal gradient across Canada using a multi-scale, multi-service approach. We test ecological, built, and sociodemographic drivers of three ecosystem services, air temperature regulation, air pollution mitigation, and carbon storage, at a fine-scale (street level), medium-scale (neighbourhood level), and large-scale (city level) across the cities.
Results/Conclusions
Our results show that urban forest composition of publicly owned street trees differs across Canadian cities, with species richness varying from 114 unique species in Winnipeg to 342 unique tree species in Vancouver. Further, the built environment and sociodemographics vary widely across Canadian cities and neighbourhoods. For example, building density, measured by dividing the area covered by buildings by the total area of the neighbourhood ranges from less than 1 % to 44 % across Canadian neighbourhoods. Median income also varies greatly across neighbourhoods, ranging from $18,247 to $71,488. We expect that the differences in the natural, built, and social environments across cities will result in differences across ecosystem service capacity. For example, average land surface temperature across our seven focal cities in July 2016 ranges from 15.99 ℃ in Montréal to 41.14 ℃ in Toronto. Cities are highly dynamic and heterogeneous, varying on a uniquely fine-scale. Therefore, the capacity of the urban landscape to deliver ecosystem services is also highly spatially heterogeneous. Our multi-scale, multi-city, multi-service approach captures the importance of heterogeneity in urban landscapes and seeks to deliver greater understanding of our urban trees, and the benefits they provide urban residents.
