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Quantitative analysis and modeling of the effect of human-induced land use/-cover change on the rate and spatial pattern of desertification in the Mediterranean using novel geochemical techniques

Final Activity Report Summary - COSMERO (Quantitative analysis and modeling of the effect of human-induced land use/-cover change on the rate and spatial pattern of desertification ...)

Human-induced land use/-cover changes are causing adverse effects on the life quality of the physical environment, thereby affecting prospects for future development. Although the long-standing interest in the interaction between land use/-cover change and geomorphic processes, our present-day understanding is far from complete. The use of novel geochemical techniques, such as in-situ produced cosmogenic nuclides, is seen as offering a means of overcoming some of these problems. This technique allows the provision of long-term, natural baseline erosion rates. These rates can then be compared with modern erosion rates to quantify the impact of recent land use/-cover change on erosion.

During the first six months of this project, the geochemical laboratory facilities at the Department of Geography and Geology of the Universite Catholique de Louvain were expanded and renovated to be suited for the separation and determination of cosmogenic nuclides in soil and sediment. New equipment for mineral separation and sample preparation was acquired, and installed. The installation of the cosmogenic nuclide laboratory was coordinated with the Institute of Mineralogy at the University of Hannover, which has an outstanding expertise in this field.

Two study areas, located in Southeast Spain, were selected to quantify the effect of anthropogenic processes on desertification processes. The methodology consisted of a combination of three independent assessments tools. Firstly, cosmogenic nuclides are used to derive long-term erosion benchmarks. Secondly, these long-term erosion rate are compared with present-day erosion rates derived from reservoir sedimentation data. Thirdly, the vegetation cover of the area is characterised to quantify the effect of land cover change on the acceleration of erosion processes.

The preliminary results of our analysis indicate that modern catchment-wide erosion rates in Southeast Spain are relatively low, given the steep topography of the catchments. Land abandonment is having a positive effect on the revegetation of the steep hillslopes, and is enhancing restoration of previously degraded land. This research topic will be further elaborated in a PhD thesis on 'Quantification of the impact of historical land use change on the temporal evolution of erosion in southeast Spain during the Holocene, using a novel interdisciplinary approach'.