Premier inventaire des macro-invertébrés du fleuve Niger à Niamey comme bioindicateurs de la pollution urbaine et industrielle

The biological approach, based on the distribution of macroinvertebrate communities along the River Niger in Niamey, allows a good characterization of biological sampling stations. Macroinvertebrate sampling at each of these stations is done through kicknet, the artificial substrates and water hyacinth. This approach shows the evolution of the taxonomic richness and diversity along the stations. Thus, the taxonomic richness and diversity decrease upstream to downstream discharge points. Reference stations and stations downstream have more diversity compared to stations immediately downstream waste water discharge. It appears from the ordination of taxa that stations upstream and downstream discharges are far less polluted and contain taxa that are sensitive to pollution as Thraulus sp. Elassoneuria sp., Afronurus sp.,Centroptiloides sp.,Adenophlebia sp.,Dipseudopsis sp. et Neoperla sp. Stations immediately downstream of the brewery and slaughter seem to be more polluted with the presence of taxa such as Chironomus gr. plumosus, Syrphidae and Culicidae. The change in the taxonomic community, diversity index of Shannon-Weaver and taxa abundance are indicators of a change in water quality and habitat from upstream to downstream of the discharge points of the city of Niamey.