Oral Presentation Freshwater Sciences 2023

Beyond traditional approaches: Development of macroinvertebrate based Multimetric index for water quality monitoring in some tropical Africa lakes (#362)

Francis Arimoro 1
  1. Federal University of Technology Minna, Minna, NIGER, Nigeria

The costs associated with traditional approaches of water quality monitoring have become prohibitive while not giving reliable early warning signals on resource conditions, hence the current shift to bioindicators and multimetric indices (MMIs). Currently, the use of bioindicators and MMIs in the monitoring of water quality has gained global recognition especially on lotic ecosystems. However, there is scanty information on the use and applicability of biotic indices in aquatic resource conservation and management in the lentic ecosystems of Western Africa. This study therefore aims at developing a macroinvertebrate-based multimetric index (MMI_NCN) to assess the ecological condition of Lakes Lambata and Tagwai in North Central Nigeria. Sampling sites were clustered based on percentage disturbance score (PDS) and categorized into reference (four sites), and impaired (four sites) for each cluster, two sites from each lake. Physicochemical parameters and macroinvertebrate samplings were performed at these clustered sites along the littoral zones from April to October, 2022. A total of 40 macroinvertebrate candidate metrics were selected referring to four main groups i.e., Taxonomic abundance, taxonomic richness, diversity, and functional feeding group (FFG). From this, potential core metrics were selected based on redundancy analysis, metrics response to environmental parameters, percent discriminatory efficiency (%DE), and box and whisker plots, then incorporated into the development of MMI-NCN. The MMI_NCN developed distinguished impaired sites from reference sites and  will be a useful tool for aquatic resource managers and environmentalists to assess the ecological condition of lakes in the tropics.