Plant species and composition along livestock grazing intensity gradients in a Namaqueland (South Africa) protected area.

The study described changes in floristic vegetation structure in relation to livestock grazing intensity in a conservation area in the Succulent Karoo, South Africa. Grazing by goats and sheep is allowed in the Richtersveld National Park (a contractual National Park) which is also an area of high floristic richness and endemism. We use goat faecal pellet density,degree of trampling and percentage bare-ground at distances from the stock post as a surrogate for a gradient in grazing pressure. A stock post is the place where farmers keep, in most cases in an enclosure called a 'kraal', their animals at night and to which they return every evening after the day's herding. Twenty-seven stock posts were located in the Richterverseveld National Park; nine stock posts on flats, footslops and mountains respectively. We measured plant species richness and diversity, and means percentage cover of the various plant groth forms (including the number of species falling into each growth from category) in each of the five 10 m x 10 m plots ( each 200 m part) demarcated along a transect of one kilolometre length from the centre of each stock post. The results show that the distance from the stock post does effect grazing intensity use because densities in faecal pellets rapidly declined with increasing distances away from stock post fot all habilitats studient.Grazing increase vegetation patchiness up to 800 m from the stock post for all the habitats. The degree to which this change in species composition occured did not depend on stocking densities, suggestion that both grazing and landscape variability were responsible for vegetation changes in rangelands of that area of the Succulent Karoo biome.