A review of empirical studies of cultural ecosystem services in urban green infrastructure

Urban green infrastructure (UGI) has gained increasing attention for its potential to provide numerous benefits. Cultural ecosystem services (CES) refers to those non-materials benefits that play an important role in improving the quality of human life and environmental sustainability. However, to date, a comprehensive study on status quo of CES generated by UGI is limited, especially evaluation methods and indicators specific for UGI. In this study, we reviewed 67 empirical studies on this topic in order to identify: the geographic distribution of research; the UGI types that supply CES; the addressed CES subcategories; the effective methods and indicators for assessing CES; and the challenges and directions for future CES and UGI research. The results revealed that: (1) the majority of the studies were more focused on certain specific UGI types, such as parks, waters, and gardens, while studies that consider UGI as a network are lacking; (2) the studies tend to focus on recreation and ecotourism, followed by aesthetic values, educational values, and cultural heritage values; (3) they employed various methods and their authors tended to combine different methods in evaluation; and (4) various indicators were developed to assess CES in UGI. Based on those findings, we recommend: (1) examining more UGI types and particulars on the UGI network; (2) taking into account all services during evaluation; (3) developing more methods for evaluating CES to address specific UGI situations, especially when dealing with the evaluation boundary and the relationships between CES; and (4) focusing more on increasing the quantity and quality of indicators, which need to communicate UGI characteristics clearly without ambiguity.