Low erosion rates measured for steep,sparsely vegetated catchments in southeast Spain |
| |
| Authors: | N Sougnez B van Wesemael V Vanacker |
| |
| Institution: | 1. Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, Chile;2. Centro de Desarrollo Urbano Sustentable CONICYT/FONDAP/15110020, El Comendador 1916, Providencia, Santiago 7520245, Chile;1. Programa de Pós-graduação em Geografia, São Paulo State University (Unesp), Avenida 24A, n.1515, 13506900 Rio Claro, São Paulo, Brazil;2. Departamento de Geografia e Planejamento Ambiental, São Paulo State University (Unesp), Avenida 24A, n.1515, 13506900 Rio Claro, São Paulo, Brazil;3. Department of Geography, Facultat de Geografia i Història, Universitat de Barcelona, Montalegre, 6-8, 3 pis, 934037866 Barcelona, Spain;4. Departamento de Ciencias Históricas y Geográficas, Universidad de Tarapacá, 18 de Septiembre #2222, Campus Saucache, Chile;5. Departament de Geografia, Universitat de Barcelona, Montalegre, 6-8, 08001, 934037892 Barcelona, Spain;1. Earth and Life Institute, George Lemaître Center for Earth and Climate Research, Université catholique Louvain, Place Louis Pasteur 3, 1348 Louvain-la-Neuve, Belgium;2. Earth and Life Institute, Environmental Sciences, Université catholique Louvain, Croix du Sud 2 bte L7.05.10, 1348 Louvain-la-Neuve, Belgium;3. Laboratoire d''Hydrologie et de Géochimie de Strasbourg, EOST, University of Strasbourg and CNRS, Strasbourg, France |
| |
| Abstract: | In order to reduce widespread degradation in desertification prone areas, there is an urgent need to understand the mechanisms controlling human-induced degradation processes in semi-arid ecosystems. Southeast Spain is known as one of the most arid regions of Europe, and its landscape is marked by sparsely vegetated degraded hillsides. Large areas of dry cultivation have been abandoned since the early part of the twentieth century, and irrigated cultivation is now expanding rapidly. In this study, modern erosion rates for two mountain ranges belonging to the Betic Cordillera were assessed by direct measurements of the accumulated sediment volumes behind 20 checkdams. The volume of sediment deposited behind the checkdams ranges between 4 and 920 m3, for catchments with a drainage area varying between 1.5 and 317 ha. Our measurements indicate that mean annual catchment-wide erosion rates in these mountain ranges are generally low. The observed erosion rates are well below maximum tolerable annual soil loss rates for the Mediterranean region, as 90% of the catchments have mean annual erosion rates below 2 t ha? 1 y? 1. Our erosion data from 20 small catchments in the Betic range are lower than the results of previous erosion studies in southeast Spain that were conducted in the Neogene intramontane basins. This study deals with erosion rates on thin soils developed on metamorphic rocks, which are not often the subject of study in the Mediterranean region. In the ephemeral stream systems in the Betic range, the spatial pattern of the vegetation cover within the catchment in relation to the concentrated flow lines appears to be crucial. Our data question the direct association of steep, sparsely vegetated hillsides with enhanced soil erosion rates, and suggest that the main erosion problems are currently not located in these steep, sparsely vegetated environments of the Betic mountain ranges. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
