Urban Ecosystem Services: A Review of the Knowledge Components and Evolution in the 2010s

In an effort to reconnect urban populations to the biosphere, which is an urgent task to ensure human sustainability, the concept of urban ecosystem services (UES) has recently garnered scholarly and political attention. With an aim to examine the emerging research trends and gaps in UES, we present an up-to-date, computer-based meta-analysis of UES from 2010 to 2019 by implementing a keyword co-occurrence network (KCN) approach. A total of 10,247 author keywords were selected and used to analyze undirected and weighted networks of these keywords. Specifically, power-law distribution fitting was performed to identify overall UES keyword trends, and clusters of keywords were examined to understand micro-level knowledge trends. The knowledge components and structures of UES literature exhibited scale-free network characteristics, which implies that the KCN of the UES throughout the 2010s was dominated by a small number of keywords such as “urbanization”, “land use and land cover”, “urban green space” and “green infrastructure”. Finally, our findings indicate that knowledge of stakeholder involvement and qualitative aspects of UES are not as refined as spatial UES approaches. The implications of these knowledge components and trends are discussed in the context of urban sustainability and policy planning.