Intimations on Quaternary palaeoecology of Africa

The biogeography of Africa, as compared with that of Europe is little known and it is only in recent years that more detailed studies have been made of certain areas. Taxonomists working on groups of lower plants and animals and even on flowering plants will still find many rich new areas for collecting in Africa, while the results of these taxonomic studies are the basis of any biogeographic investigation. The study of the factors responsible for the present-day pattern of distribution of plants and animals has been initiated in Africa only fairly recently. The present intimations, which are mostly directed towards botanical problems, are therefore general in nature and are often hypothetical. They are only intended to indicate possible historical approaches to the study of biogeography of Africa. The flora and fauna of Africa, the continent for which some of the most ancient radiometric dates have been assessed, must in consequence be old in origin. The priscotropical flora of the forests, savannas, mountains and deserts of Africa has been isolated from the other continents since mesozoic times and has developed a great wealth of species especially in the Cape flora. Botanical Gondwana affinities are apparent in this southern flora, while boreal influences of a comparatively younger age are found in the mountain floras from the Sahara and Ethiopia in the north right down the length of the continent to the Drakensberg of Lesotho and South Africa. Since the breaking up of Gondwanaland the oceans have completely isolated Africa from the other Southern Continents and, during the Quaternary, the Sahara-Sindic deserts cut off, for long periods, the connections between Africa and the holarctic region. These northern routes must, however, have been temporarily open to migration of man, beast and plants during favourable intervals of the Quaternary.