The possible association between selected sediment characteristics and the occurrence of benthic macroinvertebrates in a minimally affected river in South Africa

Abstract

Forty-two families of which the vast majority associated with particles >2000 µm were found. Sediment particle sizes <2000 µm had a detrimental effect on biodiversity. The highest biodiversity was recorded at sites characterised by riffle and run habitats. Although relatively high concentrations of selected metals were present in the sediment, it was largely from geological origin and most probably not bioavailable. No significant correlation was demonstrated between variation in temperature, pH, and electrical conductivity and diversity and abundance of macroinvertebrates. Therefore, it can be concluded that, under these conditions, sediment particle size and biotope availability played a decisive role on the distribution and abundance of macroinvertebrate taxa.