Evaluation framework for multi-scale ecological infrastructure construction benefits based on nature-based solutions: A case study of Guangdong-Hong Kong-Macao Greater Bay Area

Spatially, ecological infrastructure (EI) is a multi-scale and cross-level ecological network promoting sustainable urban development. Due to the distinct features of different scales, researchers have emphasized the importance of the multi-scale EI construction, which calls for support from a framework for scientific evaluation. Thus, based on the nature-based solutions (NbS) criteria, this study proposes a multi-scale EI construction benefits (MECBs-NbS) evaluation framework with scale differences and chooses the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as a case study. The results show that: (1) the MECBs-NbS evaluation framework is fairly applicable; (2) in 2020, the ecological benefits of EI construction for building ecological security patterns at the macro-scale (GBA urban agglomeration) by around 203.63 billion RMB; for improving human-nature harmony, the ecological, physical, and social benefits of EI construction at the meso-scale (Huizhou city) were about 358.50 billion RMB; while the EI construction benefit of completing engineering tasks at micro-scale (site) was about 34.85 million RMB; (3) overall, with the built-up area as the center, as scale decreased, the EI construction benefits gradually changed from being dominated by ecological benefits to being dominated by social benefits; (4) by supporting the status quo analysis before construction and the benefit assessment following construction, this evaluation framework may not only support the planning, design and management of EI, but also serve as a crucial tool to encourage public participation and evaluate the performance of government work. This study aims to provide a new perspective on the multi-scale evaluation of EI construction that will support and improve urban resilience.