From GI, UGI to UAGI: Ecosystem service types and indicators of green infrastructure in response to ecological risks and human needs in global metropolitan areas

Abstract

Green infrastructure (GI), providing multiple ecosystem services (ESs), is considered a key way to address ecological risks and human needs faced by global metropolitan areas. However, there is no review of GI's response to multiscale risks and needs by providing ESs. To address this research gap, we used systematic review method by searching articles constructing GI based on ES evaluation and mapping from 2005 to 2021 in Scopus and Web of Science databases, and eventually selected 101 articles. We observed three research scales and GI construction forms: GI and its components, urban GI (UGI), and urban agglomeration GI (UAGI). We found that: 1) flood disasters and human demand for outdoor recreational spaces were dominant risks and needs co-faced by metropolitan areas on three scales. 2) The proportion of GI components in UGI and UAGI providing special ES for specific risk and need should be raised to avoid disservices or ES trade-offs. 3) More attention should be given to the overall ES capacity in both quantity and efficiency of UGI and UAGI networks. Finally, UAGI with superiority in function, layout, and ability to address risks and needs was proposed as a prioritized planning approach to adapt to development of metropolitan areas.