Disturbance of the Macroinvertebrate communities of bank-root biotope of a river in southern Nigeria

Abstract

The impact of disturbance on the macroinvertebrate community was investigated in the biotope of a river catchment area. A total of 56 and 18 taxa were recorded at Stations 1 and 2, accounting for 71 and 29% individual organisms, respectively. Twelve taxa were common at both stations. Baetidae (Ephemeroptera) constituted the predominant group with the 46% density at the upstream biotope of Station 1, whereas, family Hydrobidae (Mollusca) dominated numerically the downstream Station 2. Data revealed that months of sampling at stations significantly influenced the occurrence and abundance of the major groups. Three distinct patterns of seasonal affiliation among the benthos were observed. Monthly variation in species diversity occurred. The macroinvertebrate community was affected by disturbances at the downstream bank-root biotope, limiting the occurrence of life forms to a few adaptable groups.

Keywords:

• macroinvertebrate community
• disturbance
• bank-root biotope
• river system
• Nigeria
• seasonality
• abundance

Acknowledgements

I wish to thank Dr Graham De Heaume of the Preparatory Department of the international Institute of Entomology, London; Dr Chris Oke, Department of Zoology, University of Benin, for their help in securing recent literature and texts.