The organization and production of the submerged macrophyte communities in Lake Kariba

Abstract

Aquatic macrophytes play important roles in the ecology of lakes. At times in large standing crops, they dominate the littoral zone of lakes (Cattaneo and Kalff 1980, Howard-Williams and Allanson 1981, Morgan and Kitting 1984, Denny 1985, Carpenter and Lodge 1986, Machena and Kautsky 1988) forming an important land-water interface. In the process, they benefit animals and lower plants through facilitating sediment stabilization and providing habitat diversity and shelter, as well as being substrata for periphyton and sites of abundant food production for invertebrates and fish (Wetzel and Hugh 1973, Pelican et al. 1978, Ramberg etal. 1978, Howard-Williams 1981, Machena 1989). Submerged macrophytes also derive a large proportion of their nutrients from the sediments and simultaneously act as nutrient pumps (Denny 1972 and 1980, DeMarte and Hartman 1974, Best and Mantai 1978, Carignan and Kalff 1980, Carignan 1982, Barko and Smart 1986, Machena et al. 1989). In many ways, macrophytes therefore influence the diversity, abundance and population patterns of aquatic invertebrates and vertebrates, fish, crocodiles and birds.