Land transformation and its implication for biodiversity integrity and hydrological functioning from 1944 to 1999, Karkloof catchment, South Africa

Abstract

Background and objectives: Land transformation of the Karkloof catchment is described for the period 1944–1999, together with implications for biodiversity integrity and hydrological functioning.

Method: Maps of land categories were generated by using aerial photographs and a geographical information system. Property ownership and extent were mapped based on title deed searches and analysis of property grants. Implications of land transformation on biodiversity integrity and hydrological functioning were determined according to an expert approach using the analytic hierarchy process.

Results: More than half (54%) of the natural grassland area has been transformed to commercial timber plantations (427% increase) and commercial agricultural cropping (311% increase). Loss of grassland in the Karkloof catchment is considered to be representative of the general trend in the moist eastern portion of the Grassland Biome of South Africa. Both combined forest and woodland and areas of dense alien vegetation increased (26% and 397%, respectively), whereas the area under subsistence cultivation decreased (98%). Land ownership has changed from private individuals to private business entities (31%) and corporate forestry (26%). Biodiversity integrity of the catchment is estimated to have decreased by 326% and hydrological functioning for the support of aquatic biodiversity by 166%.

Conclusion: Continued pressure to change patterns of ownership and land use is expected. This is likely to occur within the global context of climate change, population growth and shortages of land and its products. Immense pressure on the land areas, and specifically water services and biodiversity, is likely to occur, with associated environmental impacts.