Abstract:
Background: Freshwater ecosystems are increasingly modified worldwide by anthropogenic
activities. Land cover change is one of the key factors responsible for stream ecosystem
degradation. The most important impact on biodiversity and rivers around the world is the change
in physical habitat due to channelization. Since 2020, Jimma city municipality is beautifying the
city where one of the activities channelizing part of the Awetu stream crossing the city, where
stream banks and riparian vegetation are being cleared.
Therefore, the main aim of this study is to compare macroinvertebrate assemblages and water
quality between the channelized and unchannelized segments of the Awetu stream .
Methods: A cross-sectional study was employed from April 28 to May 02, 2022.
Macroinvertebrates, water samples and habitat conditions were collected from 24 purposely
selected sampling sites. Eleven of the sampling sites were located in the upstream unchannelized
segment, eight sampling sites were from the channelized segment and five of the sampling sites
were located in the downstream unchannelized segment of the Awetu stream . Samples were
analyzed for different macroinvertebrate metrics and water quality parameters. Canonical
Correspondence Analysis was used to examine the overall relationship between macroinvertebrate
assemblages and water quality parameters.
Result: Upstream site has better macroinvertebrate assemblages than channelized and
downstream sites (p<0.05). The downstream site showed better assemblage though no significant
variation was observed between the downstream and channelized site (p>0.05). Regarding water
quality parameters (orthophosphate, total hardness, electrical conductivity, five-day biological
oxygen demand, chloride and temperature) significant variation was observed between
channelized and upstream sites (p<0.05). The habitat condition scores varied from 47 (poor) at
channelization to 150 (suboptimal) at upstream.
Conclusions: Upstream sites were found to have relatively high macroinvertebrate assemblages,
better water quality and good habitat conditions. The downstream sites were lower
macroinvertebrate assemblages, less habitat conditions, and poor water quality than upstream
sites. The channelized sites were the poorest habitat condition, lower macroinvertebrate
assemblages and poor water quality. Conservation of natural habitat conditions is a fundamental
requirement for the species diversity and health of a strea
