Morfología Fluvial.-Evaluation of Mediterranean plants for controlling gully erosion

Abstract

ABSTRACT In Mediterranean environments, gullies are responsible for large soil losses causing loss of fertile cropland soil, reservoir sedimentation and flooding. To limit soil loss and sediment export it is important to prevent the initiation of rills and to stabilise gullies. This can be done by establishing vegetation at vulnerable places in the landscape. Although in the past, the effects of vegetation on soil erosion rates were usually predicted using above-ground biomass characteristics only, plant roots also play an important role in protecting the soil against erosion by concentrated runoff. Especially in conditions where the above-ground biomass becomes very scarce (e.g. due to drought, harvest, overgrazing or fire) the effects of vegetation will be underestimated when only above-ground plant characteristics are taken into account. Unfortunately, information on dryland vegetation characteristics, especially on their root characteristics and their suitability for gully erosion control is often lacking. A methodological framework to evaluate plant traits for this purpose is absent as well. Therefore this paper presents a methodology to assess the suitability of plants for erosion control and its application to 25 plant species, representative for a semi-arid Mediterranean landscape in SE Spain. In this analysis determination of suitable plants for gully erosion control is based on a multi-criteria analysis where both above- and below-ground plant characteristics were taken into account. The scores for the indicators were represented on amoeba diagrams, indicating the beneficial and the weak plant traits, regarding to erosion control. The methodology developed in this study can be applied to other plant species in areas suffering from gully erosion in order to select suitable species for restoration purposes.