An integrated cost–benefit assessment of invasive Acacia dealbata Link. restoration in Galicia (Northwest Spain): Combining remote sensing and contingent valuation to support decision-making

Invasive alien species (IAS) are linked to the extinction of numerous organisms, being a problem for which urgent measures must be taken. Their management requires robust decision-support tools capable of integrating ecological, economic and social impacts. Cost-benefit analysis (CBA) has been highlighted by bodies such as the European Union as an important tool for making sound decisions in IAS management. This study focuses on the restoration of plots invaded by Acacia dealbata in the SAC Sil Canyon (NW Spain), using a novel integrated assessment framework that links remote sensing and contingent valuation (CV) within an extended environmental CBA. Sentinel-2 data and a Random Forest algorithm were used to map Acacia plots with an accuracy of 98%, given that no data on the occupancy of the species were available for this location. Knowing the Acacia distribution made it possible to characterize the slope and location of the plots in order to estimate the restoration costs. The intervention yields benefits in terms of timber from native species and non-market benefits, which were monetized by CV, obtaining a median willingness to pay of 6.31 €/year over 50 years. All costs and revenues were incorporated into the CBA to assess the feasibility and impact of the project. After a sensitivity analysis using a Monte Carlo simulation, the restoration was found to produce a net present value (NPV) of 2,793,476.09 € over a 120-year horizon, with the non-market goods contributing most to this amount. The results demonstrate that integrating remote sensing and stated preference methods within an extended CBA provides a sound basis for evaluating IAS management alternatives, supporting transparent and evidence-based environmental decision-making in protected areas.