Biodiversity and water health status of four rivers in the East Cameroon region

A study on the biodiversity and health status of the waters of four stream in the East Cameroon region was conducted from December 2018 to December 2019. Physicochemical parameters were measured following Rodier's recommendations, while benthic macroinvertebrates were collected following the multihabitat approach. The physicochemical analyses show that the waters of the streams in the East Cameroon region are well oxygenated (70.16%), slightly acidic (5.18 UC), with low values of nitrogen and phosphate compounds (0.48 mg/L) indicating low litter decomposition. A total of 12558 benthic macroinvertebrates were collected on the 4 streams studied and divided into 3 phyla, 5 class, 12 orders, 33 families and more than 56 genera and species. The largest number of organisms collected belonged to the class Hexapoda, which represented 58.87% of relative abundance, followed by Malacostraca (33.34%). The order Decapoda dominates with 33.34% relative abundance, followed by Dictyoptera with 27.55% relative abundance. These two orders are dominated by the families Atyidae and Blaberidae in the majority of the stream studied. The Shannon and Weaver (H') and Piélou equitability (J) indices show a high diversity of taxa in the stream studied, with the exception of station Sen3, where conditions seem to be very unfavourable for the development of benthic macroinvertebrates, as indicated by the physicochemical results. The Sörensen index reveals that the tax collected in the majority of the stations are inversely similar to those collected in the Sen3 station. In short, the stream of the East Cameroon region has a fairly rich and diversified population of benthic macroinvertebrates, thus testifying to the relatively good ecological quality of the water, despite the observation made at the Sen3 station, which shows the beginning of pollution of these waters.