Macroinvertebrate colonisation of artificial substrates in a Nigerian river I: gravel and leaf litter

Abstract

Benthic macroinvertebrate colonisation of artificial gravel and leaf litter substrates over periods of four to 40 days was examined in the Ogba River, Benin City, Nigeria. Of all the assemblages of organisms identified (398 individuals, 27 taxa) on different substrates, 38% occurred on gravel and 62% occurred on leaf litter. The dominant taxonomic groups were Crustacea, Ephemeroptera and Diptera. The taxa colonised the artificial substrates at different rates. Early colonisers, recorded after four days' exposure, included Adenophlebiodes sp. (Ephemeroptera), Desmocaris trispinosa (Decapoda: Crustacea) and Clinotanypus maculata (Diptera). Potamalpheops monodi (Decapoda: Crustacea) was a late coloniser recorded after 20 days' exposure. Higher diversity and evenness were recorded from the gravel substrate than from leaf litter. Sorensen's quotient and Jaccard's coefficient showed that there were similarities in the benthic fauna composition between the two artificial substrates.

Keywords: artificial substrates; colonisation; Crustacea; Diptera; dominant organisms; Ephemeroptera; freshwater ecosystems; macroinvertebrates

African Journal of Aquatic Science 2008, 33(2): 143–148