The problem of maintaining large herbivores in small conservation areas: deterioration of the grassveld in the Addo Elephant National Park

Abstract

Changes in vegetation cover and species composition in a grassland community during a six year period are reported. The grass Themeda triandra and the dwarf shrub Helichrysum rosum decreased in abundance, whereas the grass Eragrostis obtusa increased. Comparison of grazed plots with fenced plots revealed large herbivores were responsible for the increase in abundance ofE. obtusa. The abundance of T. triandra was influenced by large herbivores, but rainfall fluctuations apparently also played a role. The decline in relative abundance of/7. rosum was evidently not caused by large herbivores. Grass cover was closely determined by rainfall. A drought-induced decline in forage abundance evidently caused the buffalo population to crash.

Keywords

• herbivory, Addo, plant species composition, stocking rates, vegetation cover.