The influence of the Shire River on Liwonde National Park, Malawi, with special reference to elephant movements

Abstract

Liwonde National Park (538 km2), Malawi, is a riverine-lacustrine park. The only outlet of Lake Malawi is the Shire River along the western boundary of the park. Although elephants spend many long hours in the floodplain on the eastern bank, they never crossed the river until 1991/92 during the worst southern African drought in living memory. This study investigated the impact of the river on the floodplain and inferred the influence on elephant movements. Waterflow of the Shire River at Liwonde since 1972 was reviewed and influences of water level variations were inferred from aerial photographs and geomorphic maps. Elephants crossing the river were also observed. The period 1972-1975 had low waterflow, reaching a minimum of 180 cumecs. Elephants did not cross then, probably because the population was small (below 200) and therefore had no incentive to do so. In contrast, the period 1976-1990 was characterised by high river waterflow of up to 1050 cumecs, leading to extensive flooding. This provided water and good forage. During the drought between 1991 and 1995 little flooding occurred. The elephants over-utilised the eastern floodplain. Some crossed the river for better forage. The population had then increased to 400.