Co-developing ecosystem services indicators for sustainable local decision-making

Communities are central to social-ecological systems where environmental dynamics, development pressures, and human well-being intersect. Yet, infrastructure planning often overlooks this complexity, leading to unintended trade-offs among biodiversity, ecosystem services (ES), and community sustainability. In this study, we apply a participatory, spatially-explicit Bayesian Belief Network model to examine the environment–development–community nexus in the context of a railway development plan within a Regional Park in France. Combining biophysical datasets with stakeholder knowledge, we assess how alternative future pathways affect the supply of ES. Through three co-designed scenarios (Development, Nature Protection, and Earth Stewardship), we quantify changes in key ES indicators, including biodiversity knowledge, human health, and natural and cultural heritage values. Our findings reveal that protected and natural areas provide the highest ES supply, while infrastructure expansion reduces ES supply, especially under the Development scenario. Conversely, the Nature Protection and Earth Stewardship scenarios mitigate impacts by rerouting or concentrating pressures. By operationalizing the ES framework in a spatially-explicit and participatory manner, we conclude that development planning should integrate infrastructure placement, landscape management and societal well-being. These insights aim to effectively communicate scientific information in an actionable way.