The influence of habitat and environmental water quality on the structure and composition of the adult aquatic insect fauna of the Ethiope River, Delta State, Nigeria

Abstract

The abundance and taxonomic richness of the adult aquatic insect fauna were determined at two sites located 2 km apart on the Ethiope River, Delta State, Nigeria. Adults were collected by ultraviolet light traps and sweep nets on seven occasions between May and November 2010. Twenty-eight (28) different taxa were identified and 869 individuals were caught at sites 1 and 2 combined. The orders represented were Diptera, Odonata, Trichoptera, Ephemeroptera and Plecoptera in decreasing order of abundance. The distribution of these organisms varied from site 1 to 2 according to the different human activities, abiotic factors and riparian vegetation at the sites. Generally, the most dominant taxonomic order was Diptera, closely followed by Odonata, while the least dominant was Plecoptera. Margalef’s species richness (d), Shannon-Weiner diversity and evenness (E) indices were significantly higher (P < 0.05) at site 1.