Integrating ecosystem service mapping and participatory scenario modelling to assess wetland restoration pathways in the Lower Danube Floodplain

The Lower Danube Floodplain is a major European ecological corridor, yet an estimated 75–80% of its former floodplain has been disconnected from the river by embankment, drainage and agricultural reclamation. The resulting loss of lateral hydrological connectivity has reduced flood retention, water purification, habitat provision and landscape resilience. Restoration is therefore not only a biodiversity objective, but also a climate-adaptation and regional-development challenge. We present an integrated assessment designed to compare alternative management pathways through the ecosystem-services lens and to make their ecological and socio-economic trade-offs explicit. The study aimed to: map the capacity of Lower Danube ecosystems to supply provisioning, regulating and cultural services; evaluate how climate pressure and land-use choices interact under alternative management scenarios; identify critical vulnerabilities and restoration opportunities; and translate scenario evidence into a transparent decision-support framework that can incorporate stakeholder knowledge and inform restoration prioritisation. map the capacity of Lower Danube ecosystems to supply provisioning, regulating and cultural services; evaluate how climate pressure and land-use choices interact under alternative management scenarios; identify critical vulnerabilities and restoration opportunities; and translate scenario evidence into a transparent decision-support framework that can incorporate stakeholder knowledge and inform restoration prioritisation. We combined spatial ecosystem-service mapping with, participatory Fuzzy Cognitive Mapping (FCM) and climate change projections in order to map the landscape capacity to provide services. Geospatial inputs included land-use / land-cover, Natura 2000 layers, hydrological information and restoration-site boundaries. Ecosystem types were linked through a matrix-based assessment to selected services: agricultural and fish production; flood regulation and hydrological retention; nutrient retention and water purification; climate regulation; biodiversity support; and recreation and landscape value, while FCM incorporated stakeholder perceptions and validated the direction and relative strength of causal links. Three regional management trajectories were compared: Business as Usual (BAU), productive land-use intensification, and ecological restoration with adaptive management. They were tested against moderate (RCP4.5) and severe (RCP8.5) climate-pressure backgrounds. A more detailed application at the Bistreț–Potelu pilot site compared five configurations ranging from continued agricultural use to hydrological reconnection, wetland recovery and diversification of green–blue infrastructure. Regional prioritisation additionally considered ecosystem multifunctionality, reversibility of polder conversion and integration with protected and ecological networks. The integrated model identified four interacting vulnerability nodes: floodplain water-retention capacity, nutrient filtration and water purification, wetland-habitat connectivity, and the dependence of productive activities on artificial water-control infrastructure. Under BAU, provisioning services remain comparatively stable in the short term, but regulating services decline progressively and climatic vulnerability accumulates. Under productive intensification, agricultural and biomass provision may increase temporarily, but this pathway produces the strongest trade-off: landscape homogenisation and continued drainage reduce nutrient retention, natural pollutant filtration, biodiversity support and the capacity to dissipate hydrological shocks. These effects become more pronounced under the severe climate trajectory, when high-capacity regulating-service areas become increasingly fragmented and isolated. Ecological restoration and adaptive management delivered the highest overall multifunctionality. Progressive hydrological reconnection, wetland-habitat recovery, buffer creation and conversion of marginal agricultural land strengthened regulating services and habitat connectivity while retaining a diversified, though rebalanced, provisioning base. Cultural services also increased through improved landscape quality, recreation and education potential. At Bistreț–Potelu, full wetland restoration generated simultaneous gains across service categories, while partial and total reconnection options produced the most balanced improvement in retention, purification and biodiversity support. The BAU configuration maximised conventional agricultural provision but maintained low regulating and cultural-service capacity. Across scenarios, marginal reductions in agricultural production were compensated by gains in resilience and system functionality. Stakeholder-informed FCM validation improved the practical realism of the causal structure and revealed where technical priorities and socially perceived priorities diverged. The future of the Lower Danube Floodplain is shaped not by climate pressure alone, but by its interaction with hydrological connectivity, land-use structure and governance capacity. Ecosystem-service mapping, coupled with BBN and participatory FCM, provides a transferable approach for comparing long-term socio-ecological trajectories and communicating trade-offs to decision-makers. The findings support restoration pathways that reconnect floodplains, rebuild green–blue infrastructure and embed stakeholder knowledge in adaptive management. They also demonstrate how site-based observations and participatory modelling can be connected to regional planning and to the implementation of the EU Nature Restoration Regulation. Future work should quantify scenario-specific changes using harmonised long-term monitoring and strengthen calibration with site-level hydrological, biodiversity and socio-economic data.