Author(s)

Sylvain Tayéwo Biaou¹, Fadéby Modeste Gouissi^1*, Armelle Sabine Yélignan Hounkpatin², Zoulkanerou Orou Piami¹, Wakili Bolatito Yessoufou¹, Souradjou Orou Goura¹, Nonvignon Martial Fassinou¹

¹Laboratory of Ecology, Health and Animal Production (LESPA), Faculty of Agronomy (FA), University of Parakou (UP), Parakou, Benin.
²Pluridisciplanary Research Laboratory for Technical Education (LARPET), University of Sciences, Technologies, Engineering and Mathematics of Abomey (UNSTIM), Lokossa, Benin.

Surface watercourses are areas of very high ecological and heritage value. Macroinvertebrates are bioindicators of the health of aquatic ecosystems. The aim of this study was to assess the effects of dewatering and re-watering cycles on benthic macroinvertebrate (BMI) communities. Two data collections were carried out at two stations (Okpara 1 and Okpara 2) on the Okpara river before and after dewatering. Thus, 8 samples of benthic macroinvertebrates and 12 physico-chemical parameters (T°C, pH, Transparency, Depth, Conductivity, Dissolved Oxygen that were measured in situ, and BOD5, COD, NH₄⁺, NO₃^-, NO₂^- and PO₄^3-) were assayed in the laboratory. Canonical Correspondence Analysis (CCA) was used to match physico-chemical data to MIB families. Shannon and Piélou diversity indices were used to determine the effects of dewatering on MIBs. The increase in temperature values of pH, BOD5, COD, NH₄⁺, NO₃^-, NO₂^- and PO₄^3-, after re-watering indicates the effect of dewatering on the quality of Okpara aquatic ecosystems. The benthic macrofauna collected consisted of 62.42% insects, 0.65% crustaceans, 6.48% molluscs, 0.72% worms and 0.14% arachnids. Whereas after re-watering, 21.67% insects, 0% crustaceans, 0.22% molluscs, 7.56% worms and 0.29% arachnids were recorded. Insects, crustaceans and molluscs were more abundant before dewatering than after. This was revealed by low abundances and taxonomic richness, as well as low Shannon index values of samples collected after re-watering.

Dewatering, Benthic Macroinvertebrates, Impact, Physico-Chemical Parameters, Okpara Rivers, Nord-Benin

Biaou, S. , Gouissi, F. , Hounkpatin, A. , Piami, Z. , Yessoufou, W. , Goura, S. and Fassinou, N. (2024) Impact of Dewatering on the Spatio-Temporal Distribution of Benthic Macroinvertebrate Communities in the Okpara River, Benin. Journal of Geoscience and Environment Protection, 12, 30-43. doi: 10.4236/gep.2024.122002.