A systematic review and synthesis of trade offs and synergies among watershed ecosystem services

Watersheds, as complex socio-ecological systems, provide diverse ecosystem services (ES) vital to human well-being and environmental sustainability. Increasing spatiotemporal variability and complex trade-offs—driven by climate change, land-use transitions, and socio-economic pressures—pose major challenges for sustainable governance. This review synthesizes advances in understanding ES generation, flow, and interaction, and evaluates quantitative, spatial, and statistical approaches. Persistent challenges include methodological variability, data uncertainties, and limited integration of upstream–downstream linkages. To address these gaps, we highlight four priorities: fostering interdisciplinary frameworks aligned with climate neutrality and circular economy principles; expanding global comparative analyses to capture geographic diversity; standardizing assessments through the Common International Classification of Ecosystem Services (CICES) to enhance comparability; and embedding ES research into adaptive policies linked to Sustainable Development Goals. These directions provide a roadmap for more evidence-based and resilient watershed management under accelerating global change.