RT Journal Article T1 Synergizing scientific and local knowledge for ecosystem services assessments: A case study in northern Portugal A1 Cunha, Jacinto A1 Cabecinha, Edna A1 Villasante Larramendi, Carlos Sebastián A1 Balbi, Stefano A1 Elliott, Michael A1 Ramos, Sandra K1 Maritime spatial planning K1 Participatory mapping K1 Regulation and maintenance ecosystemservices K1 Social–ecological systems K1 Stakeholder perceptions AB Integrating scientific and local ecological knowledge on ecosystem services (ES) is essential for effective and inclusive environmental management. Such an integration strengthens societal engagement, supports policy implementation and helps reduce sectoral conflicts across marine sectors.This study explored this synergy by assessing stakeholder perceptions of local ES and comparing them with existing scientific assessments in the NW coastal area of Portugal. Stakeholders representing four societal sectors (Quadruple Helix framework) prioritized regulation and maintenance ES (RMES), identified RMES supply areas and pressures, and outlined a 20-year vision for the region.Stakeholders classified 16 of the 20 RMES as ‘Very Important’, particularly erosion control, buffering mass movements, coastal protection, or climate regulation. Estuaries and northern coastal areas were identified as RMES supply hotspots. Ten major activities were identified, as well as conflict areas in coastal and estuarine regions, and some marine areas, particularly where fishing, tourism and potential future offshore wind farms overlapped. The stakeholder 20-year vision aligned with environmental policies, advocating an increase in ecosystem-based management (EBM) approaches and effective management of human activities to ensure the maintenance of natural capital.Comparisons between stakeholder and scientific-based maps revealed broad agreement in nearshore areas but discrepancies offshore. While for nearshore regions stakeholders were able to complement the information of the scientific-based maps for ES supply and pressures, less knowledge of offshore regions was observed from the stakeholders.This study highlighted the value of integrating scientific and local stakeholder knowledge to support informed decision-making, filling knowledge gaps and establishing stakeholder priorities for ecosystem management in marine regions that can support more complete, equitable and effective marine planning. PB Wiley and British Ecological Society SN 2575-8314 YR 2026 FD 2026 LK https://hdl.handle.net/10347/46472 UL https://hdl.handle.net/10347/46472 LA eng NO Cunha, J., Cabecinha, E., Villasante, S., Balbi, S., Elliott, M., & Ramos, S. (2026). Synergizing scientific and local knowledge for ecosystem services assessments: A case study in northern Portugal. People and Nature, 8(3), 633–649. https://doi.org/10.1002/pan3.70261 NO This research was funded by the project Mar2Protect (GA N° 101082048) funded by the European Union Horizon Europe DS Minerva RD 20 may 2026