Economic valuation of Mediterranean Ramsar coastal wetlands under conservation and climate change scenarios

This study provides a spatially explicit economic assessment of 133 Ramsar-designated wetlands located within 10 km of the Mediterranean coastline under conservation and climate-induced degradation scenarios. We apply a meta-regression–based benefit transfer framework that combines the value function developed by Ghermandi et al. (2010) with the scarcity-adjusted projection methodology proposed by Brander et al. (2012). The approach estimates site-specific marginal annual ecosystem service values under a 2024 conservation baseline, and projects changes in ecosystem service values to 2050 under a conservation scenario and three alternative degradation scenarios. Two degradation scenarios assume uniform reductions in wetland extent (22.5% and 40%), while a third uses country-specific loss rates that reflect spatial heterogeneity in climate exposure and vulnerability. Results reveal substantial spatial and typological heterogeneity in marginal values and projected ecosystem service value losses. Under all degradation scenarios, marginal per-hectare values increase as wetland area contracts, reflecting scarcity-driven economic adjustments embedded in the valuation function rather than improvements in ecological performance. Aggregate ecosystem service value losses rise with the severity of wetland reduction, shaped by differences in wetland extent, typological composition, and surrounding socioeconomic conditions. Robustness analysis confirms that comparative patterns remain structurally stable across alternative central-tendency measures, despite right-skewed value distributions. The findings contribute spatially explicit, policy-relevant insights to support conservation prioritization and strategic restoration planning in Mediterranean Ramsar coastal wetlands, particularly where projected losses in ecosystem service value are most pronounced.