Macrobenthic fauna have recently been widely used as bio-indicators for their ability to reflect the various disturbances in aquatic ecosystems. They have recently been used to assess the ecological health of streams in the East Cameroon region. This study aims to reveal the ecological health of four streams by studying the variations in the population of benthic macroinvertebrates collected in them. Sampling was done from December 2018 to December 2019 for a total of 13 months spread over four collection seasons. Kohonen's self-organising map (SOM) was performed for the various distribution patterns of the organisms collected. Discriminant factor analysis (DFA) was used to identify the parameters that characterise these patterns observed in the environment. Four groups of macrobenthic populations were observed. The distribution of benthic macroinvertebrates in these streams was spatial, temporal and discriminated by variable mineralization parameters and sediment grain size. The distribution of taxonomic richness is linked to the environmental conditions of the stations, which appear to be more or less stable, highlighting a stress gradient on the organisms. The station (Sen3), with unstable conditions, is the site of anthropic activities due to its proximity to residential areas, which are enriched in organic matter and, as a result, abound in pollutant-resistant species such as diptera (Chironomus holomelas, Chironomus sp1 and Chironomus sp2). The population of the other well differentiated groups is subject to light anthropogenic disturbance.

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.