FLUVIAL ADJUSTMENTS TO SOIL EROSION AND PLANT COVER CHANGES IN THE CENTRAL SPANISH PYRENEES |
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Authors: | SANTIAGO BEGUERÍA JUAN I LÓPEZ-MORENO AMELIA GÓMEZ-VILLAR VIRGINIA RUBIO NOEMÍ LANA-RENAULT JOSÉ M GARCÍA-RUIZ |
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Institution: | Instituto Pirenaico de Ecología, Zaragoza, Spain;Division Landscape Dynamics, GIS and Hydrology, Utrecht University, The Netherlands;Department of Geography, University of León, León, Spain;Department of Geography, Autonomous University, Madrid, Spain |
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Abstract: | ABSTRACT. Until the middle of the 20th century, Pyrenean rivers were characterized by braided channels, unstable sedimentary structures and an almost complete lack of plant cover in the alluvial plain, due to the high sediment yield in hillslopes and the occurrence of frequent and intense flooding. This was probably related to strong demographic pressures, including the cultivation of steep slopes, frequent fires, deforestation and overgrazing. Depopulation and farmland abandonment resulted in plant recolonization in formerly cultivated areas, causing a decrease in runoff and sediment yield. As a consequence, most Pyrenean rivers tend to reduce the width of the alluvial plain and to replace the braided pattern with an incised, somewhat meandering pattern, involving the construction of new terrace levels and the stabilization of fluvial bars. |
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Keywords: | fluvial adjustments sediment yield fluvial incision farmland abandonment Central Spanish Pyrenees |
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