EFFECTS OF RECREATIONAL ACTIVITIES ON THE LITTORAL MACROINVERTEBRATES OF ETHIOPE RIVER, NIGER DELTA, NIGERIA

摘要

Littoral macroinvertebrate assemblages at four stations in Ethiope River, Nigeria corresponding to different catchment land uses and recreational activities were sampled from October 2011 to May 2012 using kick sampling technique along with physico-chemical water parameters. The waters of Ethiope River were in general, transparent, acidic with low pH values ranging from 4.6 to 6.4, reasonably well oxygenated (4.4-6.8 mg/L), of low conductivity (<38.0 uScm~(-1)) except in Station 2 where conductivityreached up to 47.2 uScm~(-1) during peak of rainy season. Significant spatio-temporal variation was observed in relative abundance, with Diptera dominating the study area. Ephemeroptera, Plecoptera and Trichoptera dominated the headwater stations, whereas Coleoptera, Oligochaeta and Chironomidae dominated recreational sites. Significant relationships were recorded between physico-chemical parameters: conductivity, BOD, temperature, and nutrients and occurrence of specific taxa, mainly Neoperla, Caenis,Baetis, Enallagma, Gyrinus, Leptonema, Rhematobates and Chironomus. Distribution of organic matter, macrophyte cover, substratum texture, recreational activities and current velocity accounted for variations in species composition, taxonomic richness andtotal abundance at four stations sampled. Significant changes in macroinvertebrate assemblages were primarily due to changes in water quality. Littoral macroinvertebrate communities proved to be good indicators of water quality and should be used as bioindicators in long-term monitoring of this river.