Spatial variations of aquatic macroinvertebrates assemblages in response to anthropogenic activities in Comoé River (middle catchment, Bettié Côte d’Ivoire)

This study aimed to assess the impact of anthropogenic disturbances on aquatic macroinvertebrates assemblages in the middle catchment of the Comoé River and its tributary, the Manzan River. Five sampling stations were selected based on varying levels of human-induced perturbations and monitored over four field campaigns from March 2021 to March 2022. Environmental variables such as temperature (°C), pH, conductivity (µS/cm), water depth (m), dissolved oxygen (mg/L), turbidity (NTU), ammonium (mg/L), nitrite (mg/L), nitrate (mg/L), phosphate (mg/L) and suspended matter (mg/l) were recorded across stations in order to have a closer approach of species distribution according to abiotic variables. In total, 8,547 individuals representing 6 classes, 15 orders, 54 families and 103 taxa were identified. Insects, particularly Heteroptera and Ephemeroptera, were dominant respectively in Manzan and M’Basso stations. Taxonomic richness was highest at Pont Bettie and lowest at Manzan, where diversity was also poor (Shannon-Weaver index = 1.5). The proportion of pollution-sensitive taxa (EPT) was highest in M’Basso station (59.77%) and lowest in Manzan station (6.27%). A focused principal component analysis (FPCA) showed that environmental variables such as pH, dissolved oxygen, turbidity, conductivity and suspended matter, influenced aquatic macroinvertebrates.