Aquatic Macro-Invertebrate Diversity and Abundance in Eleyele Lake, Ibadan, Oyo State, Nigeria

Abstract

The availability and quality of water system in 21st century plays a vital role in the growth and survival of all living organisms. Eleyele Lake is a general-purpose water body which supplies water to various communities in Ibadan metropolis. This research aimed to investigate the quality of the water using physico-chemical parameters and their influence on the diversity, abundance and distribution of aquatic macro-invertebrates of the lake. Monthly, sample of water and macro-invertebrates from April to September, 2021 at eight sampling points were done, using standard APHA and Winkler’s methods. Macro-invertebrates collected were identified using standard identification guides. Relationship between physico-chemical parameters and aquatic macro-invertebrates was determined using Pearson’s correlation coefficient (r). Species diversity, taxa richness, evenness and similarity were determined using Simpson, Shannon-Weiner, Margalef, Evennes and Equitablity. A total number of 670 macro-invertebrates belonging to 7 orders namely, Hemiptera (47%), Odonata (20%), Diptera, Coleoptera, Lepidoptera, Trombidiformes and Hygrophila were collected and identified during the study period. Positive correlations occurs between BOD, EC, TDS, Nitrate and Phosphate and Chironomus sp. Also, pH was positively correlated with Lestes sp. and Aeshna sp. while DO have negative correlation with Lethocerus sp., Physa sp. and Lymnaea sp. The physico-chemical parameters and the diversity indices of macro-invertebrates encountered indicated that the lake was moderately polluted and tends toward degradation as a result of indiscriminate discharge of domestic, agricultural and industrial effluents into the Lake. Therefore, proper management of the lake is required to prevent further deterioration.