Distribution and abundance of benthic macroinvertebrates in Angereb reservoir ecosystem in Gondar, Ethiopia

Abstract

Benthic macroinvertebrates are organisms that are found at the bottom of water body living on or in the substrate. They have many applications like bioindicators of aquatic biodiversity. Investigations on distribution and abundance of benthic macroinvertebrates in Angereb reservoir in Gondar, Ethiopia, revealed that Angereb reservoir was poor in macroinvertebrate diversity in that only 16 taxa of macroinvertebrate belonging to 13 orders and 5 classes were recorded. Class Insecta was the most diverse group (9 taxa) followed by Gastropoda (3 taxa), Clitellata (2 taxa) and the least diverse classes were Malacostraca and Rhabditiphora having one taxa each. The genus Physa covers the maximum percentage abundance (12.8%) followed by family Chironomidae (10%). The pH and conductivity of Angereb reservoir water were varied among stations significantly and nitrate concentration seasonally. In addition, phosphate concentration of was higher than the standard value of lakes and reservoirs. The diversity indices showed that the macroinvertebrate diversity varied among the sampling stations. The Angereb reservoir water was polluted which was evidenced by its dominance by pollution tolerant macroinvertebrate, genus Physa. The physicochemical characteristics of water determined the abundance and composition of macroinvertebrates in Angereb reservoir.