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Support for biodiversity and ecosystem services highly variable across green alleys
Isabella C Richmond, Kayleigh Hutt-Taylor, Johanna Arnet, Lauren Bianco, Antonia Vieira Zanella, Carly D Ziter
Cities worldwide are increasingly including green infrastructure in their policies to improve sustainability due to their assumed ecological benefits. However, it is not clear if green infrastructure delivers the benefits that policies claim. We selected a popular type of green infrastructure, green alleys, and tested if they can provide ecological benefits and/or ecosystem services in cities. To test this, we conducted ecological surveys and resident interviews in green alleys, traditional “grey” alleys, and adjacent streets in Montreal and Trois-Rivieres. Using interviews, we selected a group of ecosystem services that residents mentioned as important to them. Overall, green alleys were more likely to provide higher ecological benefits, such as the proportion of native trees when compared to streets and grey alleys. However, green alleys often provide a similar or lower level of ecosystem services compared to grey alleys or streets. For example, tree size, an important aspect for residents as revealed by our interviews decreases by an average of 3.90 cm in green alleys compared to grey alleys in Montreal. Overall, the levels of ecological benefits and ecosystem services were highly variable across green alleys, indicating that management of these spaces, at the resident or municipal level, can vary greatly and determine the benefits received. Also, in the current context, green alleys often offer lower levels of ecosystem services than grey alleys and streets on average, indicating that their management is not aligned with the desired outcomes of residents, offering a path for improvement and reflection.
