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Ecological Assessment of Lake Hora, Ethiopia, Using Benthic and Weed-bed Fauna


H Gashaw
S Mengistu

Abstract

Urbanization and human settlement in close proximity to the Ethiopian lakes are among the potential causes of changes in water quality and quantity. The drastic changes occurred into one of the Bishoftu crater lakes (Kilole) best exemplify this phenomenon. The purpose of this study was ecological assessment of Lake Hora using benthic and weed-bed fauna. Samples of benthic and weed-bed were collected monthly from September 2009 to March 2010 at 3 sampling stations (A, B, C), with a standard Ekman grab. Station A is in front of Ras Hotel, Station B is place of Irecha and station C was to the south crater of the lake. The benthic and weed-bed fauna of Lake Hora included a total of 6958 individuals within 27 taxa belonging principally to Copepod (2812) and Chironomidae (1460) and Ecdyonuridae (735). A high number of organisms were observed mainly at stations B and A (3198 and 2342respectively). The correlation result indicates that oxygen showed strong relation to benthic and weed bed fauna distribution and abundance. There were high number of individuals, taxa diversity, evenness and grate number of rare taxa of benthic and weed-bed fauna at stations A and B, but these stations were affected by the community around the lake area for different reasons (for example washing clothes, boat parking and others).However low density and abundance of macroinvertabrates at station C could be due to: low organic matter load at station C which was free of human interactions; steeply slope geographical setting of the profoundly and its catchment and low vegetation cover. The Family Biotic Index result for all the sampling stations was 7.55, according to Hilsenhoff Family Biotic Index this value is indicating likely severe organic pollution and very poor water quality in all sampling sites. As this research finding indicates Lake Hora needs protection management strategies to maintain its sustainable use.

Keywords: Benthic Fauna, Ethiopia, Lake Hora, Specimens, Weed-bed


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eISSN: 2220-184X
print ISSN: 2073-073X