Green infrastructure space and traits (GIST) model: Integrating green infrastructure spatial placement and plant traits to maximize multifunctionality

Abstract

Vegetated green infrastructure (GI) is used as a sustainable complement to traditional stormwater infrastructure in many cities and is reported to provide additional benefits such as heat island mediation, crime reduction, increased property values, improved air quality, improved human well-being, improved aesthetics, biodiversity conservation, and carbon sequestration. However, we hypothesize that the simultaneous provisioning of multiple benefits – multifunctionality – is not guaranteed yet may be achieved by planning two critical components of GI: the spatial placement of GI within a city and the traits of the plant species used to vegetate GI. We propose the Green Infrastructure Space and Traits (GIST) model, a new planning tool for evaluating and maximizing GI multifunctionality based on optimizing both site selection and plant traits in GI design to promote urban planning with higher sustainability and benefits to humans. GIST involves identifying priority areas for GI placement and using plant species with traits that maximize benefits and multifunctionality in priority areas. As a case study, we apply GIST to Philadelphia, USA, and identify new locations for GI and plant traits that would increase multifunctionally across the city. For the nine benefits we examined, GIST indicates high potential for multifunctionality for the Philadelphia GI system. An assessment of the GI planning in Philadelphia to date indicates that the actualization of this multifunctionality has not been fully realized and could be improved with strategic GI placement and plant species selection. Further, we identified a cluster of correlated benefits which may be a common pathway for multifunctionality across cities. Overall, our work supports the hypothesis that multifunctional GI is possible when proper planning tools that integrate spatial placement and plant traits are used.