The role of the littoral zone in the functioning of a shallow tropical lake ecosystem

Lake Chilwa (Malawi) is a shallow tropical lake surrounded by an extensive zone of littoral swamp mainly composed of Typha domingensis. The data produced show that the physical and chemical conditions are different and more varied in the littoral region when compared with the open lake. Primary production in the littoral is confined almost entirely to Typha domingensis, which also acts as a nutrient pump by absorbing nutrients from the soils and eventually releasing them into the lake waters. Long term and short term exchanges in organic and inorganic materials between the littoral swamps and the open lake are described. These, as well as available evidence on the distribution, reproductive habits and diet of certain faunal groups, indicate that the littoral region of Lake Chilwa has an important regulating influence on the functioning of the whole lake.