The use of Landsat imagery for the identification of the remaining West Coast Renosterveld fragments, Western Cape Province, South Africa

Landsat 7 ETM+ imagery from November 1999 was used to map the remaining fragments of West Coast Renosterveld, arguably the most transformed vegetation type in South Africa. A combination of supervised and unsupervised classifications was used. These showed that Renosterveld was not definitively discernible using spectral techniques. Our final map suggested that 7.9% remained, mainly untransformed, within a region defined by combining the boundaries suggested by previous researchers (Cowling and Heijnis 2001, Low and Rebelo 1996). Using a predictive envelope based upon geological, pedological, altitudinal and rainfall data we estimated that 9.4% of the original extent of Renosterveld remained within the west coast lowlands. We examined boundary effects along the base of the Western Fold Mountains, and showed how soil mixing and coarse-scale maps had the potential to result in an 18.4% overestimate of the amount of spectrally-identified West Coast Renosterveld remaining.