Behaviour of large mammals during the formation of Lake Kariba

Bibliography: pages 132-140.The present study sought to make use of conditions during the formation of Lake Kariba, which resulted from the impoundment of the Zambezi. Three important factors led to changes in the ecology of the Kariba Basin, an area of 2,109 sq. miles, inhabited by primitive tribesmen and supporting extensive populations of large game mammals. In chronological order these were: i) the evacuation of the native inhabitants; ii) the preparation of fishing grounds; and iii) the inundation of almost the whole floor of the Central Zambezi Valley. The removal of the people resulted in large areas, especially those on or adjacent to fertile alluvium, which had been over-populated, being fallow until either cleared for fishing or submerged by the lake. The bush clearing of selected areas designated for fishing-grounds resulted in the destruction of most vegetation, while the filling of the Lake transformed a terrestrial environment, bisected by a seasonally fluctuating river, into a large static body of water within four and a half years. The habitat thus eliminated was typical of dry marginal areas in Rhodesia, the remaining strongholds of large mammals in the territory. This paper aims at describing some of the effects of the formation of lake Kariba on large mammals and their response not only to flooding, but also to the over-populated conditions which arose on islands on which they became marooned. In so doing it is, however, necessary to touch on the influence of past human settlement on the distribution and abundance of large mammals and on the effects of the clearing of incipient fishing-grounds. It is also convenient to mention briefly some of the most obvious responses of other groups of animals, as they showed certain similarities with those of mammals