During the 20th century, Mediterranean mountain areas experienced a decline in agricultural, livestock, and forestry practices, resulting in land marginalization and natural vegetation growth, with critical consequences for water resources. This research evaluates the effects of different post-abandonment land management strategies using nature-based solutions (NbS), on streamflow under climate change scenarios at various spatial scales. The study is carried out in northern Spain at two spatial scales: a small catchment, San Salvador (0.93 km2), a large catchment, the Estarrún River basin (77.4 km2), both located in the Central Spanish Pyrenees and a large catchment, the Leza River basin (274.2 km2), located in the Iberian System. An eco-hydrological modeling exercise was developed using the Regional HydroEcological Simulation System (RHESSys). Four scenarios of land management after revegetation were used and compared to a scenario of no management: shrub clearing and forest management were applied at the river basin scale, and two silvicultural treatments of equal intensity (uniform successive thinning and group selection thinning) were applied at the small catchment scale. The results show that the selected land management practices reduce evapotranspiration, leading to an increase in streamflow. Shrub clearing is more effective than forest management, although the area for shrub clearing practices may be limited due to geographical and environmental conditions. The conclusions highlight that land management should be a key strategy to improve water resources in Mediterranean mountain areas, especially in the face of climate change.
Acknowledgments: This research was supported by the MOUNTWATER Project (TED2021- 131982B-I00) funded by the MCIN/AEI/10.13039/501100011033 and NextGeneration EU/PRTR, and the LIFE MIDMACC project (LIFE18CCA/ES/001099) funded by the European Commission.