Effects of terracing and land use management techniques on hydrological connectivity and water yield in a Mediterranean mid-mountain basin

Mid-mountain catchments across the Mediterranean basin undergone a decrease in runoff and sediment yield during the second half of the 20^th century mainly due to forest cover increase following rural abandonment together with a transition to drier climatic conditions. In the same way, due to the revegetation and afforestation processes these zones experienced the homogenization of the ancient cultural landscapes, which have several consequences from ecological, geomorphological and hydrological points of view. During last decades, land use management of these areas have become a target of environmental policy makers and stakeholders to ensure the sustainability of ecosystem services. In some areas have been applied an active management through the reduction of vegetation density or by human afforestation, while others undergone a natural process of revegetation. In these setting, the conservation status of agricultural terraces plays a key role on the overall catchment response in terms of overland flow and sediment transport due to its potential effects on water and sediment connectivity between the hillslopes and the main channels. In this context, assessing the contribution of different land use management on runoff is fundamental for addressing water management and soil loss at the catchment and regional scales, especially in a context of climate change. Within this background, the aim of this work is to analyse the relative effects of terracing and land use management techniques to hydrological connectivity and water yield in a Mediterranean mid-mountain basin. To pursue this objective, we applied hydrological connectivity (IC index) and ecohydrological (RHESSys) models to different sub-catchments of the Leza Valley (Iberian System, Spain), representative of five different landscapes: (i) natural revegetation; (ii) natural revegetation with terracing reconstruction; (iii) human afforestation; (iv) human afforestation with terracing reconstruction; and (v) shrub clearing.

This research is part of the MANMOUNT project (PID2019-105983RB-100/AEI/ 10.13039/501100011033) funded by the MICINN.