Distribution and community composition of mammals in relation to land use in Botswana

Abstract: The savannas of Botswana are heterogeneous ecosystems where the animal species richness has a clear link to the spatial heterogeneity as well as to plant species richness and interspecies interactions, like competition. The human population has increased exponentially with the introduction of new foreign productive systems of land use and large herds of livestock. There has been a change from wild to domestic herbivore dominance with heavily grazed savannas and an increase of woody vegetation, which often show signs of low species richness. This study investigates the effects that different land uses have on mammal communities in northern Botswana and compares the results with previous studies from the mentioned study area and an additional area in southern Botswana. Mammals, wild and domestic, from the size of tree squirrel and larger and ostriches were recorded along 11 predetermined transects in four land use types; Communal Grazing Areas, Fenced Ranches, Wildlife Management Areas and National Parks. This study indicates that decline in species richness in an area can many times be connected to an increase in human presence. The limited number of wild species observations in the unprotected areas is an indication of how the human population and high densities of domestic animals are influencing the wildlife in those areas. The herbivores are shown to have a very evident impact on the vegetation. In this study woody vegetation of all heights are positively correlated to the areas holding large herds of domestic livestock. Land use types are shown to be the most influential environmental variables in both study areas, independent of season or patterns of precipitation. It is evident that different land use regimes affect mammal communities and vegetation structures differently.