Department of Chemistry and Chemical Engineering, University of Malawi, Chirunga Road, Zomba, Malawi, University of MALAWI
Abstract
This study was carried out in the city of Zomba which happen to be the formal capita of Malawi. Three rivers where selected which are: Likangala, Mulunguzi and the Domasi river with each of the rivers having particular characteristics. The Likangala catchment is affected by increasing population which has resulted in urban sprawl. It also originates on Zomba Plateau and flows into Mulunguzi Dam which provides water to Zomba city. The Domasi River collect all the effluent from Domasi market and prison. Generally, 9 sampling stations were studied in 3 streams of the Zomba urban town and a total of 98 taxa were identified, in which 96 were identified to the species or generic level and 2 to the family level. These taxa belong to 3 phyla (Arthropods, Mollusca and Annelids), 4 classes (Crustaceans, Insects, Gastropods and Achaeta), 12 orders and 50 families. Arthropods are the most diversified with 2 classes, 9 orders, 49 families and 92 morphotypes. There are followed by Mollusca with a single class, order, family and 3 morphotyps. The Annelids has just a single family with 2 species. The class of Insects in the most represented with 90 morphotypes divided into 8 orders and 46 families. The Mollusca have 3 species in 2 families and 1 order while the Annelids showed 2 species in a single family. The class of crustaceans had just a single family and species. Of the 8 orders identified in the class of insects, that of Hemiptera is the most represented with 27 taxa and 11 families, it was followed by the Diptera (19 taxa and 7 families), Coleoptera (16 taxa in 7 families), Trichoptera (9 taxa and 9 families), Odonata (8 taxa and 5 families), Ephemeroptera (6 taxa and 5 families) and finally we have the Plecoptera and Aquatic Lepidoptera with just 1 taxon and family each.
Key words: Biodiversity, macroinvertebrates, abiotic factors, three streams, Malawi.