Characterization by benthic macroinvertebrates and some environmental factors of streams in the East Cameroon region

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.