Excerpt
To the European eye, the Karoo is an ancient landscape untouched by major climate change or glaciation and evolving through erosional processes since deposition of Jurassic rocks, uplift, and the break up of Gondwana about 180 million years ago (McCarthy and Rubidge 2005). This break up marked the end of ~300 million years of sedimentation, largely under arid conditions, and a ~2 million year episode of violent volcanic eruptions and the outpouring of basaltic lava covering virtually the whole of southern Africa. Since this time, the interior of South Africa has been dominated by erosion (McCarthy and Rubidge 2005).
The evidence of relatively recent landscape degradation is ubiquitous and has been noted in reports, diaries, and articles for over 100 years (Hoffman and Ashwell 2001; Hoffman et al. 1999; Beinart 2003). In many respects, the situation is similar to semiarid landscapes in the Midwestern United States and in Australia. Gully systems and, in some cases, badlands have been assigned to the influence of European farming systems and in particular to the introduction of large numbers of domesticated sheep and cattle, thus destabilizing hillslopes and impacting rivers (Patton and Schumm 1975; Fanning 1999). Others have emphasized the contribution of subtle changes …
Footnotes
John Boardman is deputy director of the Environmental Change Institute and reader in geomorphology and land degradation, University of Oxford, UK. He is an honorary professor at the University of Cape Town. Ian Foster is a professor of environmental science at the University of Westminster, UK, emeritus professor of geomorphology at the University of Coventry, UK, and a visiting professor at Rhodes University, South Africa.
- © 2008 by the Soil and Water Conservation Society
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.