An Ecological Study of the Vegetation on the Eastern Escarpment of Eritrea Ethiopia

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Date

1984-06

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Addis Ababa Universty

Abstract

An ecological study of the vegetation on the Eastern Escarpment of Eritrea from an altitude of 190 meters to an altitude of 2075 meters above sea ;level Vias performed. seventy-seven stands \o[ere selected systematically and all plants found in the stands \o[ere recorded as present. A number of environmental factors including slope, aspect, altitude and percentage of rock cover at the surface \vere measured. Soils sample Vlere also taken from each stand and analysed for texture organic matter, color, conductivity, pH and the cations K, Ca, Mg; Na and Mn. The vegetation data Vlere analysed by tVlo"vIaY indicator species analysis and 10 homogenous groups of stands were formed. The groups of stands Vlere compared for their averaged environmental factors using the t-test. Rank correlation was also computed for the averages of the different environmental factor in each stand grouP. The groups of stands Vlere observed to shoVi the highest number of contrasts in altitude. Altitude in itself does have any effect on the distribution of vegetation, but it is associated with changes in atmospheric pressure, moisture, temperature and other factors. In the study region the amount and distribution 6f moisture was the factor that Vias mostly highly associated with altitude. It can thus be said that the main cause for the variation in vegetation on the Eastern Escarpment of Eritrea was the difference in moisture. Variaticn of moisture betIVeen the stands IVas also accompanied by variations in soil physical and chemical characteristics and topoqraphic factors. Ordination studies IVere also performed using detrended correspondence analysis, reciprocal averaging and IVeightedaverages ordination. The results from these studies confirmed the findings from the classification by the two-way indicator species analysis.

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Eritrea Ethiopia

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