Spatial and temporal variations in soil erosion and deposition due to land-levelling in a semi-arid area of Basilicata (Southern Italy)

This paper examines the changes from 1955 to 2002 in soil erosion and deposition due to changes in land-use patterns in the semi-arid territory of Craco, which is characterized by landsliding and badland erosion. The area underwent continuous degradation during the last century due not only to its lithological vulnerability but also to the anthropic pressure favoured by the introduction of Common Agricultural Policy (CAP) measures, which has led to the reclamation of scrub lands and badlands for durum wheat cultivation. Our analysis integrates the Unit Stream Power Erosion Deposition (USPED) model with a geographic information system (GIS) to quantify erosion risk and predict deposition patterns. Soil data, land use inventory, digital elevation data and climatic atlases were used as resource data sets to generate USPED factor values. The obtained results correlate well with field measured erosion data by other researchers. In the investigated 47 years, stable areas decreased by about 280 ha (3-8% of the total surface area), largely attributable to the increase of the low and moderate erosion intensity without significant change in sedimentation. Results from this study have implications related to understanding the geomorphic response of sites that were abandoned following remodelling due to the application of the F measure of Regulation CEE 2078/92. The average annual erosion rates estimated for abandoned and remodelled sites are respectively 15-99 and 10-64 t ha(-1), meaning that the total amount of erosion in 20 years could be estimated at around 100 t ha(-1). Copyright (C) 2007 John Wiley & Sons, Ltd.