Effects of Mediterranean shrub cover on water erosion (Valencia, Spain)

Mediterranean forest areas are ecosystems on fragile equilibrium and under the pressure of a range of degradative processes that increase the risk of desertification. Soil erosion is one of the most serious processes of degradation in these areas. To diminish its effects different approaches have been traditionally used most of them based on mecanic structures (bench terraces, ditches, etc.). Biological approaches like the planting of shrubs for soil protection have been scarcely studied. Because of this lack of information and experience, the influence of typical forest Mediterranean shrub vegetation on soil erosion processes and its comparison with two foraging species (Medicago arborea L. and Psoralea bituminosa L.) is the objective of this study. It has been observed that natural vegetation gives always the best protection, reducing comparatively a 74.96% of soil loss. However the tested species, mainly Medicago arborea, show good protection rates reducing a 37.60% of sediment production.