Post-abandonment management strategies influence future soil organic carbon storage and water resources

Mediterranean mountains have been identified as a hotspot for Climate Change. This shift is compounded by farmland abandonment and the subsequent changes in land use and cover linked to rural exodus. Understanding the consequences for different ecosystem services and developing strategies to address these challenges is essential in the context of Global Change. This study, conducted in the Leza Valley (Spain), investigates how three post-abandonment strategies-shrub clearing for pasture creation and agroforestry, secondary succession, and afforestation-could influence soil organic carbon (SOC) storage and water resources. Four climate scenarios from the IPCC (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) were selected for two-time frames (2035-2065 and 2070-2100), utilizing two predictive models: CarboSOIL for SOC stock assessment and RHESSys for streamflow projections. Although the effects of Climate Change were expected to reduce SOC stocks over time, these reductions were offset by increases resulting from all management strategies compared to current values. Afforestation was found to yield the greatest increase in SOC stocks in both the medium- and long-term, followed by secondary succession. Shrub clearing and agroforestry emerged as the most effective management for streamflow projections, with potential increases of up to 40 % under the SSP2-4.5 scenario by the end of the century. This strategy also stands out in an integrated soil-water balance, offering a combination of environmental and socio-economic benefits. Predictive models have proven to be valuable tools, helping with planning and decision-making in a Global Change scenario.