The effects of urban density on the provision of multiple health-related ecosystem services

Cities globally are expanding at an unprecedented rate, requiring an understanding of how to grow cities in a way that minimizes environmental impact while providing ecological benefits to people. Compact cities are often advocated for due to reduced impacts on biodiversity. However, increased development within an existing urban footprint may lead to loss of ecosystem services (ES) if accompanied by a loss of green space. We use spatial data and remote sensing approaches to explore relationships between urban form and indicators of health-related ES (temperature regulation, air pollution regulation, green space accessibility) at 250 study sites across a range of percent building cover in Montreal, Canada. We ask: 1) How does building cover and associated landscape structure affect multiple biophysical indicators linked to health-based ES? 2) Is population density related to ES provision at the scale of investigation once building cover is accounted for? Relationships between building cover and ES provision varied across the studied indicators. Loss of greenspace accompanying increased building cover did not affect air quality, for example, which depended strongly on pollutant sources. However, increased building cover – and accompanying vegetation loss – was a strong driver of higher daytime temperatures. For ES provided by greenspace access, there was a trade-off between the ability to provide public vs. private greenspace; suggesting public greenspace should be prioritized to maximize ES provision. Overall, our findings support that urban densification must be pursued with consideration for the overall landscape structure, and prioritize maintenance of vegetation in particular.