ASSESSING GULLY EROSION OCCURRENCE IN FOREST LANDS IN CATALONIA (SPAIN)

Gully erosion is an important land degradation process affecting soils around the world. This paper studies gully erosion in forest lands, analysing related local and environmental factors influencing its occurrence in Catalonia (north-east Spain). The data on gully erosion are based on observations from the Third Spanish National Forest Inventory, and include 157 plots with gully erosion and 9932 non-eroded plots for reference. The variables studied as potentially related to gully erosion occurrence included characteristics of the forest plots and variables describing drainage areas, such as land use configuration and edaphic and geological characteristics. For evaluating these factors affecting on gully erosion occurrence, a binary logistic model with stepwise selection of variables was used. The final model explained 30.4% of the variance. According to the results, the probability of gully erosion occurrence was increased with larger drainage area, steeper slope, presence of fine textured soils, increased urban land use and presence of unpaved roads. On the other hand, the dominance of forest and the presence of paved roads on the drainage area diminished gully erosion probability. The presented model can be used for mapping the areas with higher gully erosion risk, in an effort to direct land use planning and management in order to mitigate soil losses. Copyright (C) 2016 John Wiley & Sons, Ltd.