Towards integrated management of sandy anthropogenic shores: Developing tools for the exploration of human-natural interactions

Sandy Anthropogenic Shores (SAS) are coastal systems created or modified through large-scale sand nourishment, aiming to integrate flood safety, ecological, and recreational goals. While previous research has primarily focused on natural processes and flood protection, this study explores the underexamined interactions between human activities and biophysical systems to support integrated SAS management.

The first objective applied a Participatory Modelling (PM) approach to investigate how management activities influence SAS multifunctionality. Through interviews and workshops with stakeholders, key management goals, drivers, and indicators were identified and organized into a Collective Cognitive Map (CCM). The CCM highlighted the complexity of SAS and served as a tool for qualitative assessment, stakeholder dialogue, and knowledge gap identification.

The second objective focused on recreational behaviour using seasonal surveys (2021–2023) at the Sand Motor and Hondsbossche Dunes. Visitors were categorized as local, day, or overnight, and grouped into three motivation clusters: socialising, relaxation, and sports. The results showed that natural elements, such as beach width and vegetation, strongly attract nature-oriented visitors and influence spatial use. These insights informed the development of an Agent-Based Model (ABM) to simulate recreation dynamics.

The third objective used the ABM to examine how recreational layout and weather conditions influence visitation intensity and its spatial distribution, which in turn affects biophysical elements such as vegetation. The model tested scenarios with varying facility placements and weather patterns to assess their impact on high- and low-visitation zones.

The fourth objective explored how visitor movement and environmental factors affect vegetation dynamics, focusing on early growth stages using ABM. A vegetation sub-model simulated growth, germination, and mortality based on key parameters. Sensitivity analysis showed that horizontal growth rate and germination rates were most influential.

The integrated Recreation–Vegetation ABM revealed complex feedbacks between human use and ecological development. Scenario analyses, despite parameter uncertainties, offer valuable insights for adaptive SAS design and management. The study recommends future integration of morphological change models to capture all key SAS functions and better support multifunctional coastal planning.