| Abstract |
The Swartland region in the Western Cape of South Africa is situated in a Mediterranean climate zone, affected by large gullies that are widespread in occurrence on commercial farms. Despite gully erosion being recognized as a major land degradation process, especially in Mediterranean climates, these large gully scars in the Swartland are believed to be inactive remnants of the past. Due to this belief, gully erosion research in the Swartland is a topic that has long been ignored. To address this research shortfall, a field-based case study of a classic, discontinuous gully system in the Swartland was done. Sediment movement was measured at hillslope scale and discussed in the context of rainfall data and field observations of gully activity. The results showed that the gully system was an active sediment source, but also a conduit for sediment from hillslopes. Notably, ploughed contour banks, a measure introduced to curb gully erosion, are causing the expansion of the gully network, in addition to delivering sediment from hillslope sources to the gully system. Vegetation cover was found to reduce gully erosion temporally by up to 91.6% during the case study period. This case study illustrates that large gully channels are not mere relics of the past, but complex erosive systems that require further field-based investigations to develop an understanding of the dynamics involved. |
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| Citation |
Olivier, G., Helmschrot, J. & de Clercq, W.P. (2018) Are large classical gully systems inactive remnants of the past? A field-based case study investigating sediment movement In: Climate change and adaptive land management in southern Africa – assessments, changes, challenges, and solutions (ed. by Revermann, R., Krewenka, K.M., Schmiedel, U., Olwoch, J.M., Helmschrot, J. & Jürgens, N.), pp. 146-154, Biodiversity & Ecology, 6, Klaus Hess Publishers, Göttingen & Windhoek. doi:10.7809/b-e.00317 |
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