Study on Macroinvbertebrates Abundance and Community Structure of Lake Kuriftu, Ethiopia
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Date
2010-07
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Addis Ababa University
Abstract
The aim of the study was to investigate the abundance, diversity and community structure
of macrobenthos in relation to some environmental variables. Benthic macroinvertebrates
of Lake Kuriftu were sampled on a monthly basis from September 2009 to February 2010.
Ekman grab (0.0225m2) samples were obtained from three stations. Organic matter
content of the bottom sediment was determined by loss on ignition method. Benthic
macroinbvertebrates were identified and their distribution was reported in relation to
depth, bottom substrate, organic matter content, dissolved oxygen and macrophytes.
Bottom samples of the lake contained larvae of insects, Oligochaetes, and Nematodes. In
this study a total of 20443, 18251, and 4388 ind/m2of benthic macroinvertebrates were
collected from littoral, profundal and benthic regions, respectively. Diptera larvae were
the most abundant benthic macroinvertebrate in littoral, profundal and benthic regions
with mean abundance of 12545, 14003 and 3215 ind/m2, respectively. Chironomidae
larvae were highly abundant in profundal region. Ephemeroptera and Oligochaetaes were
also numerous in littoral and profundal zones. Diptrea larvae and Oligochaetes were
consistently found in the sediment at all depths. The abundance of benthic
macroinvertebrates was correlated with temperature and depth. Bottom substrates from
benthic and littoral were clay in texture and sandy clay in profundal region. The result
shows that vegetated littoral regions of the lake bottom had similar and higher organic
matter content than the bottom of the non-vegetated regions (profundal and benthic). The
littoral region had highest diversity (H = 1.26) and richness (d=2.72) and benthic
community density20443 ind/m2. In Lake Kuriftu Benthic fauna were concentrated in the
littoral region in association with macrophytes. The profundal region is also colonized by
numerous macroinvertebrates probably due to suitability of the bottom substrate. The
overall variation in benthic mcroinvertebrates abundance and community structure in Lake
Kuriftu were due to the slight variation of physic-chemical and sedement quality.
KEY WORDS: Benthic macroinvertebrates, Kuriftu, Littoral, Macrophytes, Profundal
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Keywords
Benthic macroinvertebrates, Kuriftu, Littoral, Macrophytes, Profundal