How Development of Recreation, Embryo Dune Habitat and Flood Safety Interact at Evolving Nature-Based Sandy Interventions

Socio-economic pressures on coastal zones demand innovative solutions for balancing human needs and natural dynamics. This study investigates how recreation, embryo dune habitat development, and flood safety interact within nature-based, multifunctional sandy anthropogenic shores (SAS), focusing on two Dutch case studies: the transient Sand Motor and the permanent Hondsbossche Dunes. Utilizing qualitative and quantitative methods, including interviews, surveys, sensors, and advanced modeling tools (Agent-Based Models and the Cellular Automata model DuBeVeg), we explore socio-bio-physical dynamics and long-term landscape evolution. Results show that recreational activities influence vegetation establishment, affecting embryo dune formation and thus habitat size. While high recreational pressure restricts embryo dune formation, this enhances foredune growth, strengthening their functionality as flood defense. However, with restricted embryo dune development, ecological value is compromised. Our findings highlight the need for design strategies that balance these competing objectives. Further recreational use scenario analyses, for different SAS designs, including morphological design and spatial design of facilities, could uncover whether it is also possible to achieve synergy among recreation, flood safety, and ecological value of SAS.