The current configuration of protected areas in the Cape Floristic Region, South Africa - reservation bias and representation of biodiversity patterns and processes

摘要

The formulation of a strategic plan for the conservation of terrestrial biodiversity in the Cape Floristic Region (CFR; 87,892 km(2)) requires an objective and spatially explicit assessment of the representativeness of major habitat categories (surrogates for biodiversity) currently under protection. A GIS layer of statutory and non-statutory conservation areas was used, along with layers of many biological and physical features, to explore the configuration of conserved areas relative to key biological and physical indicators. Three analyses were performed. (1) Recursive partitioning, a classification-tree analysis technique, was used to contrast features of protected areas with non-protected areas. (2) The conservation status of 16 primary and 88 secondary Broad Habitat Units (BHUs; derived on the basis of topography, geology, homogeneous climatic zones, and floristic composition) was assessed in terms of prescribed conservation targets. (3) The extent to which protected areas are able to sustain ecological and evolutionary processes was explored by assessing the extent of spatial components of these processes for all conservation areas. About 20% of the CFR is protected in some form of conservation area, mostly concentrated on sandstone substrates, and areas with high altitude and steep slopes. The reservation bias towards upland areas has seriously constrained representation of biodiversity pattern and processes. Most of the habitat diversity is poorly represented in the current conservation area system with only 9% of the remaining primary BHUs in the lowlands conserved. However, almost 50% of the Mountain Fynbos Complex is conserved (largely exceeding its conservation target). Spatial components of the ecological processes identified are poorly captured by the conservation area network although faunal and floral migration is possible in the uplands due to the strong spatial connectivity of the protected network.