Bioindicators of lotic and lentic ecosystems in Agbede wetlands (Southern Nigeria), using macroinvertebrate tools

Abstract

Macroinvertebrates are globally acclaimed as essential tools for biological monitoring in freshwater ecosystems. The essence of this study was to establish bioindicators for Agbede wetlands located in Edo- North in southern Nigeria. Both lotic (stations 1–3) and lentic (stations 4–7) water bodies were sampled between December 2012 and May 2014. Standard methods were applied for macroinvertebrates collection from the littoral habitats. The results of physicochemical parameters indicated that; flow velocity influenced the lotic environments, while temperature, electrical conductivity and turbidity mostly influenced the lentic water bodies. Three major pollution indicator groups were realised across the ecotypes and they are; the pollution sensitive (Ephemeroptera, Coleoptera and Trichoptera), the facultative (Anisoptera, Zygoptera and Decapoda) and the pollution tolerant groups (aquatic snail, Oligochaete and Leech). Pollution tolerant group was preponderance across the study stations but was significantly predominant in the lentic stations, especially during the dry seasons (November to March). The performance of pollution tolerance index (PTI) model, biodiversity indices and Multivariate analyses; all showed high taxa abundance, species composition and diversity across the stations. Similarly, PTI model revealed moderate water quality particularly in the lentic stations (values between 17 and 18) indicating healthy ecosystems, which was also proven by the biodiversity indices. The implication of this work is that, it will remain a comprehensive guide on biomonitoring programmes of the water bodies and the catchment areas as the water bodies are not in a bad quality.