Evaluation of the ecological quality of streams based on the Hilsenhoff Biotic Index (HBI) in Daloa (Centre-West ; Côte d'Ivoire)

The aim of this study was to determine the structure and diversity of macroinvertebrates and to assess the ecological quality of streams in the town of Daloa on the basis of macroinvertebrate structure using the Hilsenoff biotic index (FBI).Macroinvertebrate sampling was carried out in the four streams using a Van Veen bucket and a haul net over an area of 1 m (2 m *0.5 m).The benthic community structure was then studied using the Shannon-Weather diversity and Pilou equitability indices.Next, a Canonical Correspondence Analysis (CCA) was carried out to highlight the relationships between the distribution of macroinvertebrate families and physicochemical parameters.Finally, the Hilsenhoff Biotic Index (HBI) was calculated to assess the ecological quality of these streams.The results showed that a total of 2,626 macroinvertebrate individuals, divided into 146 taxa, 07 classes, 20 orders and 63 families, were identified in the various streams.The structure of this macrofauna indicates that it is made up of 81.51% Arthropods, 16.44% Molluscs and 2.05% worms-Annelids.The Insect class was the best represented, with several orders including Diptera, Hemiptera, Coleoptera and Odonata.The order Diptera was the most dominant.The diversity analysis revealed that the macroinvertebrate communities in the streams of the town of Daloa are diverse and balanced.The distribution of macroinvertebrates was strongly influenced by temperature, conductivity, dissolved oxygen, transparency, turbidity and pH.The calculated FBI index values indicated that the streams in the town of Daloa were of Good to Fair quality.