نبذة مختصرة : International audience ; Purpose: Erosion and its spatial distribution in three agricultural headwater catchments were assessed in the border of the volcanic plateau in Southern Brazil. We analyzed terrain, hydrological processes and land use influence to provide a comprehensive assessment of the catchments' sensitivity to erosion.Methods: Topographic attributes were acquired from a digital elevation map, WaterSed model was parametrized to simulate runoff, diffuse erosion and sediment yield, and sediment source contributions were estimated using sediment fingerprinting based on near-infrared spectroscopy. Results 2 According to the modeled results, areas covered by crop fields, grasslands and those adjacent to the drainage network are the most sensitive to erosion. Short distances from the source to the river network and the occurrence of high magnitude rainfall events (80 mm) promoted increases in connectivity for runoff/sediment transfer. Erosion simulations show that areas of low infiltration, as unpaved roads, were important runoff generators during lower volume rainfall events (25 mm). Sediment fingerprinting provided satisfactory results: to quantify the contributions of unpaved roads to sediment (~39%). Topsoil and stream channels were also significant sediment sources for the set of analyzed samples, corresponding to average contributions of 38 and 23%, respectively. Conclusion Areas sharing geomorphological similarities did not lead to similar sediment contributions. Vegetation cover controlled erosion in topographically sensitive areas. Unpaved roads provide a significant sediment source, followed by topsoil and stream channels. The complementary results provide useful insights to better coordinate planning environmental conservation strategies in these fragile landscapes.
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