Influence of Environmental Factors on Species Richness and Diversity in a Semi-Arid Environment, South Africa

Abstract

The Nama Karoo biome is one of the least well-studied biomes in the semi-arid region of South Africa, and essential baseline biodiversity data for this region are lacking. The aim of the present study was to examine the influence of environmental factors on the species diversity and richness of Mountain Zebra National Park, South Africa, which includes this vital biome. Vegetation data were obtained using the step-point method. Both species richness and diversity were unaffected by slope, aspect, coarse fragments, and soil texture. Multiple linear regression analyses indicated that a combination of four variables (nitrogen, clay, and sand contents, and longitude) should be included in the optimal model for species richness, and the optimal model for species diversity also revealed four influencing variables: soil organic carbon, clay and sand contents, and longitude. Overall, both species richness and diversity could be predicted by a combination of climatic, topographic, and soil properties. The findings of this study can be used as a reference for the effects of environmental factors on plant species richness and diversity in semi-arid environments.