Integrating Extensive Livestock and Soil Conservation Policies in Mediterranean Mountain Areas for Recovery of Abandoned Lands in the Central Spanish Pyrenees. A Long-Term Research Assessment

Summary

Land abandonment is a global issue with important implications in Mediterranean mountain areas. Abandoned Mediterranean croplands start a process of secondary succession that is initially colonized by grasslands, shrubs and forest. In Mediterranean mountain areas, the process is very slow, so the shrubs remain for decades, preventing livestock from accessing pastureland. Therefore, farmers have to burn or clear the shrubs in order to provide pasture, a practice that has recently been encouraged by several regional governments in Spain. Data from experimental plots of the Aísa Valley Experimental Station in the Spanish Pyrenees allow to evaluate the effects of burning and clearing shrubs on physical and chemical soil properties, runoff production and soil erosion rates. The results suggested that clearing shrubs returned more positive results than burning, as it improved soil quality and slowed soil erosion while producing slightly higher runoff coefficients, which is very important in Mediterranean environments where water is a scarce resource. Clearing shrubs improves soil characteristics by increasing organic matter and CN ratio, which promote the expansion of herbaceous species with a high pastoral value. The results suggested that the policy of clearing shrubs is suitable for managing abandoned lands in Mediterranean mountain areas. Further studies at catchment scale will be needed to confirm the impact of substituting shrubs for meadows and to understand the connectivity of the flows measured from pedon and slope to the watershed scale.