CONNECTIONS, DISJUNCTIONS AND ENDEMISM IN THE EASTERN AND SOUTHERN AFRICAN MAMMAL FAUNAS

The animals and plants of eastern and southern Africa exhibit patterns of distribution that are disjunct, continuous or restricted to just one of these two regions. Striking similarities between the distribution of animals and plants seem to have been strongly influenced by both the prevailing and historic climatic conditions. Over the last 1500 years, however, the migration of pastoralists southwards with their domestic stock seems to have had a profound effect on the distribution of the major vegetation types. which may well have strongly influenced the ranges of both animal and plant species. 42% of the southern African sub-region mammal species are restricted to the region, 48% exhibit a continuous distribution, while 10% have disjunct distributions, being absent from the extensive Brachystegia-Mopane woodlands of central Africa. The arid regions of the south are marked by a radiation of the remarkable golden moles. The more primitive mammalian groups, such as the shrews and microchiropterans exhibit extensive patterns of continuous distribution and a low level of endemism, at both the species and generic level. Ancient tectonic activity must have acted as a strong isolating influence in the distant past, but naturally-mediated climate change has had the most profound effect on the composition of faunas. During the last 12000 years, archaeological evidence from East Africa indicates that large herbivorous mammals of the arid zones were at that time found much further south, but had achieved their present distribution patterns by 8000 years BP. Accompanying these distribution changes were significant patterns of local extinction.