Biodiversity of Benthic Macroinvertebrates and water quality as a tool to the ecological study of three forest streams in the littoral zone (Cameroon)

A study of the community dynamics of benthic macroinvertebrates in relation to physicochemical water quality was conducted from December 2022 to December 2023 in the Lepp-Nyock, Ndog-Bissolo, and Ngwei streams within the tropical littoral forest area of the Guinean Gulf (Edéa). Physicochemical analyses were performed and Benthic Macroinvertebrate identified following classical method. 

The results indicate that those waters are well-oxygenated (73.72±12.48%), slightly acidic (pH 6.87±0.42 CU) and contain very low concentrations of nitrogen compounds and heavy metals (0.29±0.28 mg/l Cu, 0.8±0.54 mg/l Zn, 0.45±0.27 mg/l Mn, 1.32±0.47 mg/l Fe, 0.81±0.38 mg/l Al, 0.18±0.2 mg/l Cd, and 0.49±0.52 mg/l Cr). Biological analysis revealed a total of 8,699 Benthic Macroinvertebrates belonging to 4 Phyla, 5 Classes, 12 Orders, 55 Families and 117 Genera. Arthropods were the most abundant, accounting for 86.67% of the total, with the insect Class (86,56%) being dominant (8 Orders, 42 Families, and 68 Genera). Gastropods (13,27%) were the second most abundant group, represented by 2 Orders, 5 Families, and 16 Genera. The Atyidae family was particularly dominant within the benthic community, with Caridina africana identified as the most prevalent species. 

The Shannon-Weaver diversity index (H') and Piélou equitability index (J) indicated low taxonomic diversity, while the Organic Pollution Index (OPI) suggested a less disturbed environment. Together, these findings reflect the good ecological quality of the water in the studied streams.