Spatial and Temporal Variations in the Benthic Macro-Invertebrates of Douglas Creek, South-Eastern Nigeriak

Environmental concerns of aquatic ecosystems have become emerging issues in Nigeria. Study of the benthic macro-invertebrates of Douglas creek, south-eastern Nigeria was carried out from September 2011 –August 2013. Benthic macro-invertebrates from six classes, nine families and ten species were encountered. Maxillopoda class had the highest abundance of 47.37 %. The others were Bivalvia (18.95 %), Clitellata (15.79 %), Insecta (13.68 %), while the least were Malacostraca and Oligohaeta with 2.11 % each. Again, only Maxillopoda showed a significant seasonal variation (p<0.05). Gammarus lacustris was the most frequent and abundant species; occurring in 16 of the 24 months. This was followed by Tubifex tubifex and Anodonta grandis. Iphigenia laevigata, I. rostrata and Pisidium casertanum were the least frequent; each occurring just once throughout the study period. Gammarus lacustris, Tubifex tubifex and Hexacylloepus sp. occurred in all the stations while Iphigenia laevigata, I. rostrata and Pisidium casertanum each occurred in only one station. Margalelf species diversity and Shannon-wiener index were generally low with highest values of 1.924 and 1.591 respectively. The low diversity of benthic macroinvertebrates in Douglas creek is an indication of high anthropogenic perturbation. The presence of T. tubifex in all the stations suggests organic pollution from anthropogenic source. This study thus recommends that private and government agencies operating in this environment implement ecological surveillance and mitigation measures that will prevent further environmental degradation.

Keywords: Benthos, distribution, abundance, Douglas creek, Maxillopoda, Gammarus lacustris.