The hydrological restoration potential of small landscape depressions in the Nete catchment in Belgium: An ecosystem services-based approach

Small depressional wetlands are increasingly recognized for their contribution to hydrological regulation, carbon storage, and biodiversity maintenance. However, their small size and spatial isolation often exclude them from inventories and make them vulnerable to human alterations, affecting their natural functioning. This study assesses the restoration potential of landscape depressions in the Nete catchment within the sandy Campine region, Belgium, and how this restoration affects the provisioning of ecosystem services (ES). A topography-based delineation of 20,843 surface depressions, including 4600 potentially restorable upstream depressional wetlands was created. Then, geomorphological classification was combined with the ECOPLAN-SE model to evaluate changes in provisioning and regulating ES. Results show that depression restoration substantially increases regulating services, particularly soil carbon storage and runoff storage capacity, while provisioning services such as food production and wood production often decline. However, 41% of depressions represent “no-regret” restoration areas, meaning no negative impact on any of the assessed ES. These sites are typically upstream, permanently dry, and located outside intensive farmland. The ES assessment underscores the potential of context-specific restoration planning. Since small depressional wetlands can significantly enhance landscape-scale climate resilience by mitigating both floods and droughts, policymakers should increase their efforts to restore and preserve these valuable landscape elements. This study provides a spatially explicit framework for integrating small landscape depression restoration into regional land management and climate adaptation strategies, highlighting their critical yet underappreciated role in sustaining multifunctional landscapes.