Africa

Abstract

The pollen record of the late Pleistocene in Africa is poorly resolved due to the paucity of sites, combined with the fragmented nature of most sequences. A vegetation history of the continent can, nevertheless, be reconstructed for the last glacial maximum and reveals environments very markedly different from the present day. The most marked changes are apparent in the equatorial tropics where, although there are few terrestrial sequences of appropriate age, cooler and more arid glacial climates appear to have resulted in significant reduction in rain forest and expansion of both montane and savanna vegetation. Rain forest does, however, appear to have survived in isolated localities and, at this stage, the so-called refugium hypothesis cannot be ruled out as a valid model of tropical vegetation history during the late Pleistocene. The pollen record for other biomes in Africa is also suggestive of glacial cooling and in most cases greater aridity, although there are exceptions in the Lake Malawi catchment and in parts of southwestern Africa where precipitation may have been greater than today. Although temperature and rainfall changes are the most obvious drivers of vegetation change in the late Pleistocene, the implications of lower partial pressures of atmospheric carbon dioxide in explaining some of the changes also need to be considered.