Mapping Research Hotspots and Trends in Water Ecosystem Service Valuation: A Bibliometric Analysis

Growing water stress has made the valuation of water ecosystem services (WESs) a critical focus for achieving sustainable water management. To trace the evolution, hotspots, and trends of WES valuation, this study employs visualization tools (CiteSpace and VOSviewer) to analyze 1213 articles from the Web of Science Core Collection (1996–2025). The bibliometric analysis reveals that (1) a structural break at the end of the 2000s divides the record into a nascent phase (1996–2009) and a sustained-growth phase (2010–2025); (2) at the country level, the United States leads in both publication volume and co-authorship centrality; China, the second-largest producer, presents a relatively limited integration into international collaborative networks; (3) there are thematic shifts from foundational monetary valuation methods toward integrated ecosystem accounting, spatially explicit, model-based assessment and policy-oriented applications; and (4) the thematic shifts and emerging hotspots indicate future research priorities: coupling models with data-driven methods to improve reliability at finer scales, extending site-level estimates to cross-regional and global accounting, and developing tiered indicator systems that embed socio-economic and ethical considerations alongside biophysical ones. The study shows that WES valuation is being positioned as a governance-ready accounting framework which depends on data availability, spatial scale, and decision context.