Assessing the Effect of Environmental Stressors on the Community Structure of Macroinvertebrates and Water Quality of River Ugbalo, Nigeria

Aquatic macroinvertebrates play significant roles in the benthic zone of the aquatic ecosystem and they have different tolerance level to pollution. Globally, macroinvertebrates are usedas bioindicators in determining the ecological health and water quality status of aquatic ecosystem. Therefore, this study focused on the community structure of benthic macroinvertebrates in River Ugbalo, south-south Nigeria. Macroinvertebrates and physicochemical parameters were sampled in three marked out stations between March 2018 and February 2020. Physicochemical parameters were analyzed following standard procedures, while macroinvertebrates were collected with Kick net and Van Veen grab. Physicochemical parameters showed that the water quality of the three stations sampled were fair considering the values of pH, turbidity, sulphate, nitrate, phosphate, DO, BOD, and EC which were within the World Health Organization and Federal Environmental Protection Agency of Nigeria. Cluster analysis based on Bray- Curtis similarity showed that macroinvertebrates were clustered by stations rather than seasons. A total of 5,580 macroinvertebrates individuals were recorded showing high biodiversity in the river. Diptera was the most abundant Order with 2,488 individuals followed by Odonata with 697 individuals. The least represented Order was Lepidoptera with 13 individuals. The diversity indices showed that Margalef index (5.93), Simpson diversity (0.95), Evenness (0.63), and Shannon-Weiner index (3.30) were highest in Station 1. This research work showed that the water quality of the studied stations was fair and station 3 was the most perturbed station.  We recommend the enactment and enforcement of policies that will lead to aquatic ecosystem restoration.