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 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.

The study focused on northern Portugal coastal and marine area and used a participatory workshop with stakeholders from academia, industry, public administration, and civil society. Participants ranked and mapped Regulation and Maintenance Ecosystem Services (RMES), identified current and future pressures, and co-developed a 20-year vision for the region. Workshop outputs were digitized, aggregated into a 1-km grid, and analyzed spatially using GIS.