Benthic macroinvertebrates as indicators of water quality: a case-study of urban Funa Stream (in Kinshasa, Democratic Republic of Congo)

Abstract

Macroinvertebrates ability to indicate various types of anthropogenic stressors is widely recognized as an integral component of freshwater biomonitoring. In case of pollution, biodiversity of the aquatic community can be affected and the species composition changes from natural species to tolerant species. In this study, macroinvertebrates were sampled using Surber sampler at 5 locations from October 2007 to September 2008 to determine the environmental quality of Funa water body and to analyze fauna structure assemblages. Water physical chemical data were explored using multivariate analysis of Canonical Component to detect environmental trends. Ten biodiversity indices: specific richness S, abundance A, Shannon-Weiner diversity H’, maximum diversity Hmax, evenness J’, McNaughton ID, Redundancy R, Capacite Biogenique Secondaire (Cb2), Indice Biologique Global Normalise (IBGN) and Biologic Monitoring Working Party (BMWP) were used for biological assessment of water quality. Forty-seven species were collected from 3624 specimen dominated by Odonata, Achaeta and Diptera. Four taxa displayed higher relative abundances: Glossiphonidae (20 %), Chironomidae (9 %), Lumbriculidae (9 %) and Hirudidae (8 %). DIMO model splits up sites into two groups in function of H’, Hmax, and J’. In addition, rank-frequency diagrams characterized stage 1 and middle between stages 1 and 2 structured curves. In overall, indices showed low values, which expressed the inhospitable character of habitat structure. However, BMWP and IBGN scores of water quality worsened from upstream to downstream.