Effects of larvicide treatment on invertebrate communities of Guinean rivers, West Africa

Abstract

Biological and hydrological data collected from 1984 to 1998 in three Guinean rivers were analysed to evaluate adverse effects of biological and chemical larvicides applied for the control of blackfly Simulium damnosum, vector of the parasitic digenean worm Onchocerca volvulus. Although most of the variation in invertebrate populations were flow-related, larvicide applications affect community structure reducing the abundance of the most sensible taxa. In spite of these results, in the long term the rarefaction of some invertebrate taxa (i.e. Tricorythidae) does not cause a significant reduction of total invertebrate densities because of the corresponding increase of other taxa (i.e. Hydropsychidae and Philopotamidae). The functional structure of the communities is also not affected.