Soil erosion and sedimentation rates are frequently linked to human impact, both in the Belgian loess belt and in the Mediterranean Taurus mountain ecosystem in southwest Turkey. However, the soil cover differs strongly between both regions: deep loess soils marked by only minor erodibility variations in the loess belt, versus shallow, stony soils with bedrock at limited depth in the Taurus.
Environmental change and human impact on the landscape are well documented in both regions from archaeological findings and land use reconstructions based on pollen diagrams, supplemented by historical map study for the Belgian loess belt. Also pollen-based climate reconstructions are available, aside from the well-known historical global climate patterns.
To compare both study area’s response to historical environmental change, an adaptable soil erodibility factor was added to the existing Watem/Sedem model, which was used to estimate sediment fluxes within two small catchments of about 10 km². From both catchments detailed sediment archives were available to calibrate the model.
As soil properties in the Belgian loess belt are fairly homogeneous throughout the profile, variations in erosion rates are mainly due to environmental change, with human impact playing a major role. Even the removal of large amounts of topsoil and the surfacing of calcareous loess does not alter the erosion potential considerably. In contrast, the shallow soils of the Mediterranean Taurus are marked by increasing stone content with depth and mostly bedrock at shallow depth. Both control erosion potential to a large extent, as once the topmost soil layers are removed, increased topsoil stone content largely reduces soil erodibility. Moreover, bedrock outcrops account for a large area within the catchment and will yield no sediment at all.