Spatial-seasonal variation in species composition, abundance, distribution and diversity of Cladocera zooplankton in the Okhuaihe River at Ikpe, Benin City, Edo state, Nigeria

Abstract

Cladocera, generally known as water fleas, are microcrustaceans that assist as biological indicators of water quality. This study observed the spatial-seasonal variation in the species composition, abundance, distribution, and diversity of Cladocera in the Okhuaihe River, Ikpe, Benin City, Nigeria, from August 2021 to January 2022. By means of standard methods, six families encompassing 75 individuals were documented. Station 4 recorded the highest abundance (64 individuals), while station 1 had the lowest (three individuals). Chydoridae (33.33%) was the most dominant family, trailed by Sididae (26.67%), Moinidae (16.00%), Daphniidae (14.67%), Bosminidae (8.00%), and Macrothricidae (1.33%). Species richness and diversity were at their peak in station 4 and lowest in station 2. Evenness was highest in station 1, while dominance peaked in Station s. Daphniidae exhibited a positive correlation with turbidity, while Macrothricidae correlated positively with sulphate and turbidity. The study established that the Okhuaihe River maintains good water quality, with a Cladocera community characteristic of tropical freshwater habitats, but with low diversity. The diversity of Cladocera did not fully mirror the physicochemical conditions. Continuous monitoring is suggested to detect water quality deviations early, as subsequently increased anthropogenic activities could negatively influence and impact species abundance, richness, and diversity.