Macroinvertebrate communities in the erosional biotope of an urban stream in nigeria

Macroinvertebrate communities in the erosional biotope of a Nigerian stream were studied at three stations. The numbers of taxa recorded in these stations were similar. The total abundance and the abundance of major invertebrate groups in particular was not significantly different between stations. The dominant and subdominant taxa at these stations showed slight variability in qualitative composition. The relative abundance of all major invertebrate groups showed irregular temporal variations at all three stations, but the magnitude of these variations was lesser at station 2, the construction site, suggesting increased faunal stability. Margalef’s taxa richness (D) at station 2 was high, but Shannon-Wiener general diversity (H) and evenness (E) were almost similar at all stations; statistically, these indices were not significantly different. The temporal fluctuations in taxa richness and general diversity at the three stations followed the same seasonal trend approximating normal curves. The taxonomic composition of faunas was similar at all stations. Macroinvertebrate communities of the erosional biotope are compared with those of the bank-root biotope at all stations; the fauna of the erosional biotope was less sensitive to the perturbation caused by construction activities than that of the bank-root biotope.