Sand dredging impact on macrobenthic invertebrates of a hallowed river in Delta State of Nigeria

Abstract

River Ethiope is one of the most revered water bodies in Delta State by communities along its course. Macroinvertebrate samples were collected from threes communities; Obi- Iloh, Ebedei-Adonishaka, Ebedei Obi-Ukwuole designated as Station 1, 2 and 3 respectively, that forbids women entrance but allows men folk to sand dredge. The survey conducted between March and April, 2015, identified 17 taxa of macro invertebrate with 219 individuals. Of the nine order, Hemiptera constituted the most abundant set 42.25%, followed by Decapoda 16.90%, Coleoptera 11.74%, Plecoptera and Arachnida 6.57%, Odonata 5.16%, Diptera 4.23%, Annelida(Lumbriculida and Arhynchobdelida) 3.76% and the least Trichoptera 2.82%. However, non-statistical significant richness exists among these organisms at the stations (p ≥0.05). Computed biological indices and lower macro invertebrates census revealed that the macro invertebrates were more abundant in stations 3 and 1 than in station 2, identifying the last two stations as unstable and moderately deteriorated. The enlisted significant correlated variables expressed manifold hydrological factors pinpointing human disturbance as impact.