Macroinvertebrate community of a post lindane treated stream flowing through derived savannah in southern Nigeria

Abstract

The study of Macroinvertebrate community of the Edion River was carried out from January to June 2007. Water and benthic samples were collected from three stations monthly and fortnightly respectively. The physico-chemical characteristics include pH (7.05 - 7.98), dissolved Oxygen (DO) (2.50 - 6.67mgl^-1), biological Oxygen demand BOD5 (1.10 - 4.80mgl^-1), Alkalinity (12.20 - 73.20mgl^-1) and Turbidity (0.01 - 1.19NTU). The values recorded were found to be within the range of tropical freshwaters. A total of 43 taxa comprising of 532 individuals, were collected from the study area. Of the total number of individuals recorded, stations 1, 2 and 3 had 207, 190 and 136 respectively. The dominant orders were Diptera (40.15%) and Ephemeroptera (36.96%). The diversity of macrobenthic invertebrates varied at the stations, with taxa richness highest at station 1 (index, 5.63) and lowest at station 2 (2.67). Water temperature was significantly correlated with dissolved Oxygen and Odonata, while pH was positively correlated (p>0.05, r = 0.5) with most of the parameters. All the parameters except water level and the macrobenthic invertebrate did not show any significant difference (P>0.05) at the study stations. The low relative abundance of the species may be attributed to the impact of human activities along the river catchment area.

Keywords: Macroinvertebrates, dominant, taxa, physicochemical parameters, inland water, Nigeria.