Identifying linkages between urban green infrastructure and ecosystem services using an expert opinion methodology.

Stormwater green infrastructure (GI) has the potential to provide ecosystem services (ES) that are currently lacking in many urban environments. Nevertheless, while stormwater GI presents a major opportunity for cities to enhance urban ES, there is insufficient evidence to link the complex social and ecological benefits of ES to different GI types for holistic urban planning. This study used an expert opinion methodology to identify linkages between 22 ES and 14 GI types within a New York City context. An analysis of results from five interdisciplinary workshops engaging 46 academic experts reveals that expert judgement of ES benefits is highest for larger green spaces, which are not universally considered for stormwater management, and lowest for vacant land and non-vegetated GI types. Overall, cultural services were identified as those most universally provided by GI. The results of this study highlight potential significant variations in ES benefits between different GI types, and indicate the importance of considering cultural services in future GI research and planning efforts. In the current absence of robust quantitive measurements linking ES and stormwater GI, increased qualitative insight could be obtained by expanding the methodology used in this work to include non-academic experts and other urban stakeholders. We therefore offer recommendations and learnings based on our experience with the approach.