THE USE OF A 60-YEAR SERIES OF AERIAL PHOTOGRAPHS TO ASSESS LOCAL AGRICULTURAL TRANSFORMATIONS OF WEST COAST RENOSTERVELD, AN ENDANGERED SOUTH AFRICAN VEGETATION TYPE

ABSTRACT

Four West Coast Renosterveld sites (the Kapokberg and the Contreberg, the Koringberg-Swartberg complex and the Elandsberg Private Nature Reserve (PNR)) were examined by means of a series of aerial photographs taken at approximately ten-year intervals since 1938. Except for the Elandsberg PNR, which showed a slight increase, the area covered by natural vegetation at the other sites in 2000 was between 19.5% and 47.6% less than in 1938. On slopes of less than eight degrees, between 13.7% and 33.8% of the 1938 extent remained, while on slopes between eight and twelve degrees the amount remaining ranged between 38.0% and 74.7%. The greatest transformation was seen on the Kapokberg, while the Koringberg-Swartberg was the least affected of the agricultural sites. Most of these transformations occurred before 1988, suggesting that the Conservation of Agricultural Resources Act (Act 43 of 1983) had been effective in limiting the expansion of agriculture onto the steeper slopes. The limitations of using aerial photographs to assess the quantity and quality of West Coast Renosterveld are discussed.