Prioritizing Mangrove Ecosystem Services in Vietnam: An Integrated Fuzzy Decision-Making Framework

Coastal ecosystems in the Cat Ba Biosphere Reserve face increasing pressure to reconcile economic development with environmental protection, creating a need to prioritize ecosystem services for local management under climate related risks and livelihood transitions. This study evaluates sixteen ecosystem services by applying an integrated Multi-Criteria Decision-Making framework. To address uncertainty in expert judgment, the potential-flow-demand criteria are combined with generalized trapezoidal fuzzy numbers (GTrFNs) and the centroid index ranking method. The results reveal a precaution-oriented prioritization pattern in which regulatory services, particularly Control of extreme events and Climate regulation, receive the highest priority, reflecting a shared consensus that ecological resilience constitutes an essential foundation for the local economy. Cultural services related to leisure and tourism occupy an intermediate position characterized by a complex trade-off, where economic potential is balanced against environmental safeguards. In contrast, the invariant low ranking of provisioning services confirms a definitive forest transition where local stakeholders have permanently shifted away from direct extraction models. These findings support ecosystem service-based management approaches that emphasize safeguarding regulatory functions and reinvesting tourism related benefits into conservation to enhance the long-term resilience of forest coastal systems.