Bridging Local and Regional Scales: Ecological and Governance Assessment of Urban Dune Lake Wetlands in a Coastal Metropolis

Urban wetlands in coastal cities are under growing strain from urban growth, climate change, and governance that is often fragmented. This study evaluates the condition of the freshwater dune lakes located in the Veracruz–Boca del Río–Medellín conurbation in Mexico, a protected corridor made up of 33 dune lakes that is increasingly pressured by urban expansion. We used an interdisciplinary approach that combined ecological monitoring, legal analysis, and participatory management tools. Fieldwork included 24 h monitoring of dissolved oxygen, measurements of Biochemical Oxygen Demand (BOD₅) in representative systems, a diachronic review of the legal evolution of five Natural Protected Areas (NPAs), and community workshops to jointly design interventions. The results showed strong day–night swings in oxygen (4.0–14.8 mg/L) linked to vegetation dynamics, with nighttime hypoxia posing risks for aquatic fauna. BOD₅ ranged from 4.8 to 150.3 mg/L, pointing to severe organic pollution in the most degraded system. The legal review identified repeated patterns of environmental regression, expressed through reductions in protected polygons, the legalization of irregular settlements, and the fragmentation of protected areas through judicial processes. In response, we propose a hybrid management model that brings together riparian restoration, Sustainable Urban Drainage Systems (SUDS), green infrastructure, and participatory monitoring, emphasizing a key 100 m buffer zone. This integrated strategy aims to improve flood regulation, reduce urban heat island effects, and enhance water quality, while also reinforcing community stewardship and legal protection. We conclude that conserving these urban wetlands effectively requires adaptive approaches that connect landscape-scale and local-scale actions, which are essential for climate adaptation in rapidly urbanizing coastal regions.