dc.description.abstract |
The assessment of macroinvertebrate community of the Enfranz stream, located northwest
of Bahir Dar city in the southern part of Lake Tana, was studied in wet and dry seasons
from August 2010 to May 2011. This stream feeds Lake Tana and its total catchment area
is 198 krrr'. Four sampling sites were selected along the stream. Physicochemical
parameters, temperature, dissolved oxygen, conductivity and pH, were measured.
Macroinvertebrates were collected using standard dip net based on the Rapid Bio
Assessment Protocols for use in streams and . wadeable rivers. Most physicochemical
parameters varied significantly (P < 0.05) among sampling sites. A total of 15286
macroinvertebrate individuals, belonging to 30 families were identified. Macroinvertebrate
metrics for stream water quality assessment were calculated: total Taxon Richness (TR), %
Dominant Taxa (DT), Shannon Wiener diversity index (ff), Pielou Evenness Index (J'),
Percent Ephemeroptera (%Eph), Percent Trichoptera (%Tri ch), Hilsenhoff Family-Level
Biotic Index (HFBI) and Percent Dipterans (%Dip). Results of ANOVA showed that
macroinvertebrate metrics differed significantly among sampling sites and seasons (P <
0.05). Pearson's correlation coefficients showed that, physicochemical parameters were
significantly correlated with macroinvertebrate metrics. It was found that human activities
such as agriculture and grazing changed the bank of stream by reducing the overall water
quality and macroinvertebrates, it is recommended to create forested buffer zone that
promotes the broader diversity of habitats and protect the stream from point-source and
non-point-source pollution. Efforts to assess and monitor biological conditions in this
stream should include habitat quality assessment and comprehensive analysis of water
quality parameters. |
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