A survey of macroinvertebrate assemblage of Ikwu River, Umuahia, southeast Nigeria

Abstract

Macroinvertebrate fauna of Ikwu River, Umuahia, Nigeria was studied in the 3 stations to evaluate the composition, abundance and distribution vis-à-vis environmental conditions and anthropogenic impacts. Macroinvertebrate fauna was sampled between January and June 2016 using the modified kick sampling technique as well as sweeping of aquatic macrophytes with hand net. A total of 168 macroinvertebrate individuals comprising of four benthic fauna group and seven (7) taxa was recorded. Percentage composition of the taxa showed that aquatic snail (Bulinus globosus) was the highest (55.36%) while water spider (Argyroneta aquatica) was the least (0.60%). Spatially, Station 3 recorded the highest number of individuals (116), followed by Station 1 (28 individuals) and Station 2 (24 individuals). Diversity assessment recorded higher Shannon-Weiner diversity index (H) in Station 1(0.8058) than in Stations 2 (0.4563) and 3 (0.6978). Magalef Species Richness was highest in Station 3 (0.8415), followed by Station 2 (0.6293) and Station 1 (0.6002). Evenness Index was highest in Station 1 (0.7462) and least in Station 3 (0.4019). The diversity indices, which were a reflection of the species composition, abundance and distribution, were equally poor.

Keywords: Macroinvertebrates, environmental conditions, anthropogenic activities, water quality