Effects of land abandonment and climate change on soil erosion An example from depopulated agricultural lands in the Sudetes Mts., SW Poland

The aim of the study is to calculate and evaluate the changes in spatial distribution of soil erosion rates related to land use/cover changes and climate changes in the Sudetes Mts. within the last 150 years. Various methods were used, including GIS analysis of historical and contemporary land use/cover and climate data, spatial analysis of soil erosion modeling using RUSLE. Changes in spatial distribution of precipitation sums were estimated based on spatial deterministic-stochastic models (regression-kriging) applied to the measurement data from the entire Sudetes region in both analyzed periods. There was a pronounced increase in the area of forests and grasslands at the expenses of arable grounds due to depopulation and consequent land abandonment. These changes started already in the 1880s but they were intensified after World War II. On average soil erosion in the study area decreased by 76.2% (from 4.03 t ha(-1) y(-1) in the 19th century to present 0.96 t ha(-1) y(-1)). However, the changes in erosion are highly diverse locally in the studied region with the maximum decrease of 8-16 t ha(-1) y(-1) on steep and higher slopes, which were transformed from arable grounds to forests and grasslands. While both land use and climate changes took place in the study area, changes in land use/cover have a much larger impact on calculated soil erosion rate than climate change. The abandonment of land and the development of spontaneous succession of vegetation limited soil erosion in a very effective way. The values obtained by RUSLE modeling were compared with other values of soil erosion from various field measurements in the Sudetes Mountains in order to evaluate the model. The measurements were based on the experimental plots and sediments stored within the agricultural terraces and in the water reservoirs of various sizes. While the specific sites show large differences in denudation rates, the mean contemporary erosion calculated from our model (0.06 mm y(-1)) corresponds with the average rate of denudation, which was calculated for the entire Sudetes: 0.05-0.01 mm y(-1) (Jahn 1968). (C) 2016 Elsevier B.V. All rights reserved.