Identifying robust area-based conservation strategies to secure ecosystem service provision under uncertainties

Area-based conservation remains the principal strategy for preserving biodiversity, yet current planning approaches inadequately consider two critical uncertainties: future trajectories of socio-environmental drivers of environmental degradation and preferences for alternate conservation objectives. This study demonstrates how spatial conservation prioritization can be integrated with scenario-based simulation modelling to systematically evaluate conservation strategies under these uncertainties. We simulated conservation area expansion strategies (e.g. timing and extent of interventions) in Switzerland (2020-2060) using a comprehensive full-factorial design testing approaches across five scenarios of climate change, land-use change, and conservation priorities, with strategy robustness assessed through impacts on ten ecosystem services (ES) characterized across both space and time. Results revealed substantial variation in ES provision under alternative futures, with pronounced spatial shifts in service delivery. Critically, only limited spatial overlap existed between regions displaying the highest ES robustness and areas prioritized for protection based on current ecological value, demonstrating the inadequacy of planning approaches that ignore future uncertainties. The most consistently robust strategy for securing ES provision involved rapidly expanding conservation areas to 30% coverage (aligned with the Kunming-Montreal Global Biodiversity Framework target), prioritizing small patches in human-dominated landscapes, and employing mixed management combining both preservation and restoration. However, strategy effectiveness varied across different ES and scenarios, indicating that optimal approaches must account for societal preferences regarding trade-offs between services. This research addresses a recognized gap in conservation planning science and provides both methodological guidance for uncertainty-informed planning and specific recommendations for Switzerland's pursuit of the 30x30 target under accelerating environmental change.