Benthic fauna community structure in river Benue at Makurdi, Benue state, Nigeria

 

Author(s): Akaahan, T. J. A., Araoye, P. A., Adikwu, I.A.

Abstract: Uncontrolled dumping of wastes into rivers without control measures is widely practiced in the developing nations of the World as it is observed in River Benue at Makurdi. To ascertain the health status and integrity of River Benue at Makurdi, sediments were collected monthly from five different locations on the shoreline of River Benue at Makurdi for a period of two years (July 2011-June 2013). The sediments were examined for the presence and absence of macro benthic fauna. The result of the sediments showed that a total of 4,451 macro benthic fauna individuals comprising of 4 phyla and 21 taxa were obtained. More individuals were recorded during the dry seasons as compared to the rainy seasons. Station II (570 individuals) and Station III(649 individuals) recorded low population as compared to the other locations: Station I (1,177 individuals), Station IV (1,043 individuals) and Station V (1,012 individuals). Arthropoda had the highest population of individuals as compared to the other phyla. Pollution sensitive species of benthic fauna were not found at Station II and III which is an indication of polluted environment. There was generally low biodiversity of benthic fauna community which indicate the perturbed nature of the study area. Across the stations Shannon Diversity Index   ranged from 1.81-2.91, Margelef Diversity Index ranged from 2.10-4.44, Simpson Diversity Index ranged from 0.80-0.95, Menhinick’s Diversity Index ranged from 2.20-2.61, Pielou Evenness Index ranged from 0.92-0.94 and Simpson Dominance Index ranged from 0.28-0.47 during the study period. Diversity indices result showed a variation in the community structure of River Benue. It is recommended that the discharged of effluents and other waste into the River Benue should be controlled and enforced.

 

Fig 1: Map of Makurdi Town Showing Sample

Sites Source: Ministry Of Lands and Survey Makurdi (2011)

 

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