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This paper forms part of a long-term study of land degradation in the Klein Seekoei valley in the Sneeuberg uplands about 30 km southwest of the town of Middelburg, South Africa (Fig. 1). Landscape degradation in this area is characterized by the development of badlands on the footslopes of upland areas and by gully systems in valley bottoms (Boardman et al., 2003). Herding of domestic livestock probably has occurred in parts of the Karoo for 2000 years (Elphick, 1985; Bollong and Sampson, 1999). There is some debate whether precolonial herders caused irreversible damage to the landscape. Lovegrove (1993) states that they could have been responsible for some localized overgrazing, whereas Fox (2000) suggests that European colonialists are responsible for the dramatic increase in degradation over the last 200 years. Our work has focused on the period since European colonisation, which began in the second half of the 18th century (Raper and Boucher, 1988; Newton-King, 1999; Smith, 1999). Much of the debate on degradation in the Karoo has centred on the relative influence of climate and land management as the major contributory factors. There is some evidence in the Karoo as a whole, and in the Klein Seekoei valley in particular, that very high stock numbers (sheep largely) are the cause of vegetation change and soil erosion leading to the formation of badlands and gully systems (Boardman et al., 2003). The main objective of this study is to examine the change in extent of degraded areas and gully systems over time using data from five sets of aerial photographs. Data on the extent of crop cultivation is assessed as a possible ancillary causal factor for the observed degraded features. Reasons for changes are suggested in the light of available climatic (Keay-Bright et al., in press) and land use data (Keay-Bright and Boardman, in press-b) for the study area. Data from erosion pins (Keay-Bright and Boardman, in press-a) and sedimentation in two dams located in the study area are used to give a third dimension to the two-dimensional data obtained from the aerial photographs. Prospects for rehabilitation of degraded areas are discussed in the light of the results.