The role of soil surface conditions in regulating runoff and erosion processes on a metamorphic hillslope (Southern Spain): Soil surface conditions, runoff and erosion in Southern Spain

This study presents the results of an analysis into the role of soil surface conditions in the regulation of soil hydrology and erosive processes at one hillslope under dry Mediterranean climatic conditions. The methodology was based on the analysis of hillslope surface components and their hydrological and erosive function on a patch to scale by means of rainfall simulation and experimental plots. The results showed the existence of a complex eco-geomorphological system composed of a multitude of vegetation patches distributed at random on the hillslope, and where the presence of different surface conditions on the soil can have a sizeable influence on hydrological and erosive behavior. From the hydrological point of view, the runoff generation mechanisms follow a seasonal pattern depending on the moisture of the soil with a different spatial condition, with frequent hydrological disconnections between parts of the hillslope, as in other Mediterranean mountainous regions. Soil surface rock fragments, the layout of tussocks intra-hillslope and previous soil moisture as dynamic control factors in the hydrological and erosive processes are all important.