Synopsis: A comparison has been made between the recent densities and distributions of African mammals of the genera: Equus, Ceratotherium, Diceros, Hippopotamus, Choeropsis, Hyemoschus, Giraffa, Okapia, Damaliscus, Alcelaphus, Connochaetes, Taurotragus, Tragelaphus, Boocercus, Strepsiceros, Limnotragus, Syncerus, with those at the turn of the present century. Information has been obtained from literature, by personal contact, and in a tour of East Central and South Africa. This monograph is divided into fifteen parts, each containing the known distribution and density of a family or a subfamily. For convenience of workers in the field, for whom this work was originally intended, each part has been subdivided into political territories instead of ecological habitats. The names of some political territories have been changed during the preparation of this work but former designations have been retained for historical convenience. The maps either illustrate the distribution discussed or show some of the localities mentioned, thus obviating in part the need for a gazetteer. A bibliography concludes each part.
Within this century there has been drastic reduction in the density and distribution of most of the species considered and the prospects for the future are not encouraging, although their recuperative ability indicates that, given the necessary respite, populations can build up again in suitable areas and be of considerable economic importance to those territories where they occur. The reasons for this reduction may vary in importance from one country to another, but the main causes are:
- The destruction of habitats, from such causes as an increase in agriculture, uncontrolled burning, flooding due to the construction of dams for hydro-electric and irrigation schemes, expansion of settlements and changes brought about by natural factors such as bush encroachment and soil erosion;
- Game clearance operations such as tsetse fly control measures and preparations for ground nut schemes;
- The opening up of remote areas by the creation of roads, thereby giving better access to hunters and encouraging poachers, and interrupting game migration paths and possibly isolating small pockets of game whose numbers may be below the survival value for the species;
- The expansion of settlements and an increase in human populations leading to a greater need for meat and therefore more hunting, partial competition between the wild species and domestic animals for food, and fencing preventing dispersal of most game species;
- Commercial poaching often in or near National Parks, caused by the high market value of game meat, skin and horn;
- Alteration of the balance of species by one or more members becoming more, or less, numerous, thereby affecting other members as seen recently with the hippopotamus problem in the Queen Elizabeth National Park;
- Tribal hunting of a wasteful kind in which whole herds of animals are destroyed;
- The diversion of water supplies;
- Improvement in equipment such as firearms and transport; and
- Epidemic diseases, for example rinderpest.