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Gewählte Master / Diploma Thesis:

Solomon Akalu Desalegne (2014): ECOLOGICAL IMPACTS OF SILTATION, THE CASE OF THREE ETHIOPIAN RIVERS.
Master / Diploma Thesis - Institut für Hydrobiologie, Gewässermanagement (IHG), BOKU-Universität für Bodenkultur, pp 75. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
Soil erosion is a major environmental problem in Ethiopian highlands, where unsustainable land management practices prevail. Part of the eroded soil end in rivers with possible ecological impacts on aquatic organisms. Macroinvertebrates are good indicators of human land use impacts because they are sensitive to habitat alterations and integrate changes over time. The study was undertaken in Chancho, Keta and Orgogo Rivers in the central Ethiopian highlands with the objective of assessing the ecological impacts of siltation. From 29th October-3rd November 2013, macroinvertebrate samples were taken from the three rivers according to the Multi-Habitat Sampling protocol. Alongside, on site measurements of physicochemical parameters (T0, DO, pH and Conductivity) and depth were taken. In addition, flow velocity was estimated and water was analysed for nitrate and orthophosphate. A Choriotope type index (CIX), based on visual estimation of the different microhabitats, produced a value of 1.15, 2.55 and 4.25 for Orgog, Keta and Chancho Rivers, respectively, showing that Orgogo had the highest proportion of fine substrates and Chancho the least. Physicochemical parameters did not differ significantly among the three rivers except conductivity. Nitrate and orthophosphate measurements were with in the natural level of surface waters. Results from NMS ordination and hierarchical clustering showed that most macroinvertebrates have distinct substrate and water current preferences. Indicator Species Analysis (ISA) further indicated that macroinvertebrates have different tolerance levels to fine sediment. Metrics based on ISA and other metrics showed a change in macroinvertebrate structure and function with an increase in the level of fine sediment. The data generated from the research will help to enrich the general knowledge on macroinvertebrates in the Ethiopian ecoregion montane grasslands and woodlands and the ecological impact of siltation in Ethiopia. Moreover, the results can provide a basic information for environmental agencies for a more sustainable land use and restoration of rivers and watersheds impacted by siltation.  

Beurteilende(r): Graf Wolfram
1.Mitwirkender: Leitner Patrick

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