Exploring the relationship between urban green infrastructure connectivity, size and multifunctionality: a systematic review

Abstract Context Urban green infrastructure (GI) multifunctionality is widely valued within the academic literature, and underpins calls from policy makers to enhance and expand GI resources. However, there is a gap in understanding concerning how GI connectivity and size influence GI multifunctionality outcomes. Objectives The objectives are to: (1) present the current status of research on urban GI multifunctionality (encompassing ecosystem services and disservices) and the GI traits of connectivity and size; (2) identify relationships between these topics within the literature; (3) provide research insights and present actionable GI planning recommendations based on the findings of the research. Methods A systematic review of 139 academic sources (2010–2023) was conducted following the PRISMA guidelines. Results Key findings include that multifunctionality themes are more commonly considered within research exploring GI connectivity across urban boundaries than within them, where a wider range of flows of ecosystem functions and associated services (and disservices) are enabled. Also, research predominantly focuses on multiple large GI sites, with limited attention to the multifunctionality of single small GI sites that are commonly found in dense urban areas. Conclusions Greater consideration is needed of how the manipulation of GI size and connectivity influence multifunctionality outcomes, whilst also recognising the threat of ecosystem disservices emerging as a result of such actions. Through uncovering gaps in understanding concerning these issues, and highlighting topics benefiting from stronger research foundations, this research can support GI policy, practice and research in realising GI multifunctionality outcomes in urban settings, whilst minimising ecosystem disservices.