Composition, Structure and Functional Feeding of Aquatic Entomofauna in Kodjobou&amp;#233; Lake: Water Quality Assessment

Idrissa Adama Camara,Mathieu Kobenan Kra,Dramane Diomande,Norbert Kouakou Kouadio,Allassane Ouattara,Edia Oi Edia,Lassina Doumbia,Mexmin Koffi Konan

doi:10.4236/oje.2020.104011

Abstract

The composition, structure and Functional Feeding Groups (FFGs) of aquatic insects were investigated in Kodjoboue lake (South-East of Cote d’Ivoire) to assess water quality. Four sites (K1 - K4) were sampled during eight campaigns. At each site aquatic insects were collected using a kick-net (25 × 20 cm, 500 μm mesh size). Environmental variables were also recorded during this period. Water was collected from each sampling site for nutrient (phosphorus, nitrate) analysis in laboratory. A total of 68 aquatic insect taxa belonging to six orders and 32 families were recorded during the study. Site K4, subject to intense agricultural activity, had the lower diversity and least balanced stand with the lowest values of Shannon-Weaver index, Pielou’s Evenness index and rarefied richness. The functional approach revealed five major FFGs: predators, scrapers, shredders, gatherers-collectors and filter-collectors. Among the different functional feeding groups, the percentage of predators was higher than that of other groups at all the sites. The P/R report indicated that our four sites are characterized as heterotrophic with K1 as the least heterotrophic. Focused Principal Component Analysis (FPCA) showed that parameters of water, like pH, dissolved oxygen, nitrate were statistically correlated with species abundance. The diversity and Functional Feeding Groups metrics of aquatic insects used to describe the state of Kodjoboue lake reveal its disturbed state.

Highlights

Aquatic macroinvertebrates are the main group of organisms using to assess the ecological state of continental hydrosystems
The composition, structure and Functional Feeding Groups (FFGs) of aquatic insects were investigated in Kodjoboué lake (South-East of Côte d’Ivoire) to assess water quality
The diversity and Functional Feeding Groups metrics of aquatic insects used to describe the state of Kodjoboué lake reveal its disturbed state

Summary

Introduction

Aquatic macroinvertebrates are the main group of organisms using to assess the ecological state of continental hydrosystems. Of the biological quality elements that have been used for water quality assessment, aquatic insects are most often recommended [4] due to their varying sensitivity to several abiotic and biotic factors in the environment [5]. They constitute the most diverse taxonomic group and the most abundant in aquatic environments [6]. Functional feeding groups measures do not require standardized sampling and different sampling methods can be used to assign aquatic invertebrates to functional feeding groups [14]

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Discussion

Conclusion