Mapping the evolution of the water-energy-food-ecosystem (WEFE) nexus: A comprehensive review of the methods, scales, and sustainability challenges

• Water-energy-food-ecosystem ( WEFE) nexus research from 2010 to 2024 is systematically evaluated. • Ecosystems are integral components embedded within the water-energy-food nexus. • WEFE research shifts from static assessments toward dynamic, integrated modelling. • Unified frameworks, integrated data, and cross-scale governance should be promoted. Worldwide crises related to water, energy, food, and ecosystems are expected in the future. Although a number of studies have focused on the water-energy-food-ecosystem (WEFE) nexus, a comprehensive review that integrates bibliometric patterns, methodological approaches, and multi-scale applications within a unified WEFE framework remains lacking. To address this gap, this study applies the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review protocol and conducts bibliometric and content analyses of publications from 2010 to 2024. The results show a steady increase in WEFE-related studies and a paradigm shift from the traditional water-energy-food (WEF) triad toward a four-component framework that explicitly incorporates ecosystems. Moreover, the WEF nexus remains a central research theme. Methodological approaches can be categorized into quantitative assessment, simulation and prediction, and integrated management; however, most rely on static analysis and therefore cannot sufficiently capture dynamic feedbacks. Scale-based analysis indicates that regional and urban studies dominate the field and focus on resource integration and internal resource management optimisation, respectively, whereas transboundary-scale research remains limited. This review is the first to systematically synthesize the conceptual evolution, methodological pathways, and scale-specific challenges of the WEFE nexus within a unified paradigm. Moreover, this review identifies key directions for future research, including framework standardization, multi-source data integration, and scale-appropriate governance strategies, thereby providing theoretical insights and empirical support for advancing sustainable WEFE nexus research.