Composition of benthic invertebrates along river mpanga in relation to anthropogenic disturbance

Abstract

Research on the assemblages of benthic macro faunal community in the River Mpanga catchment was conducted during the period November 2019 - January 2020 following the standard methods to assess the status of environmental pollution. Good ecological water quality is needed to maintain the integrity of the river system and depends on the preservation of natural conditions of the water and the surrounding environment. Unsustainable and improper use and pollution through various human activities can impair and destroy the ecological state of a natural system by changing its chemical composition and the biological communities that are naturally occurring. To assess the benthic invertebrates' composition in relation to anthropogenic disturbance along river Mpanga, chemical, physio-chemical and biological data were collected along the different sections of the river. The study area includes upstream of Mpanga river, the midstream in Fort Portal, the tea estates area downstream of Fort Portal. Results from the upstream area confirm that human activities have a large influence on the physical and chemical water quality. While the impact on the general biodiversity of benthic invertebrates is less pronounced at present, the continuation of these human activities threatens the habitat availability for benthic invertebrates that depend on natural river banks and unpolluted water. Chemical and biological water quality were further lowered by certain urban pressures, which can be mainly linked to improper waste and sewage disposal, as to the absence of natural bank environments. Downstream of the urban area in Fort portal, where human pressure is less intense and where banks are less modified and protected from surrounding land use practices by a protection zone of natural vegetation, both chemical and biological quality improve. The river system recovers further as it passes through Kibale Forest Natural Park, which leaves time for suspended solids (turbidity) to settle and allows chemical and biological processes to lower the water's mineral, salt and nutrient-load.