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Title: Invasion of prosopis Juliflora(SW)DC into Awash National Park and Its Impact on Plant Species Diversity and Soil Charachterestics
Authors: HIBRETU, Demissie
Advisors: Dr Mekuria Argaw
Professor Ensermu Kelbessa
Keywords: Awash National Park,
invasive alien species,
P. juliflora,
species composition.
Copyright: Jun-2009
Date Added: 6-May-2012
Abstract: ABSTRACT The study was conducted in Awash National Park (ANP), which is located along the Addis Ababa-Djibouti highway. The study focused on the invasion of exotic alien species Prosopis juliflora (Sw.) DC. into ANP and the changes on species composition and soil characteristics that have occurred as a result of the invasion. Eight border site locations from the four directions (north, south, east and west) were chosen. A total of 32 sites were sampled from which 80 quadrats were established. From all quadrats plant species were collected and categorized into trees, shrubs, sapling, seedling, herbs and grasses. The structure of woody species including regenerations were described through the analysis of species diversity, density, frequency, DBH, height, Basal area and IVI. Percentage ground cover of herbs and grasses was included in the analysis. Soil data were collected from 32 sampling sites and analyzed for the selected parameters. A total of 122 plant species representing 79 genera and 30 families were recorded. Sites with P. juliflora had the highest diversity index and richness than sites without P. juliflora. Highest number of woody species (60%) falling under the lowest DBH class. Species under this DBH class includes P. juliflora, Acacia. oerfota, A. tortilis and Grewia schweinfurthii. Similarly, majority of the individuals (83.16%) of the species prevailed in lower height class. Particularly, the height distribution of P. juliflora was found only in the lower class. It might show that the invasion is just coming into the ANP. As compared to the other woody species in reference with frequency rank, density and IVI values P. juliflora was among the top three species, next to A. oerfota and A. senegal. The population distribution patterns of six important tree species bordering ANP reveals three types of diameter class distribution pattern and P. juliflora found under inverted J-shaped distribution pattern. The analysis from the regeneration status of P. juliflora implies the distribution of more seedling population than that of sapling and mature individuals. The analysis from ground cover percentage indicated that sites with P. juliflora had the highest percentage cover than sites without P. juliflora. Results from distribution of P. juliflora revealed that from the total of 80 sampling plots, P. juliflora was recorded in 19 plots (47.5%), out of which 9 (18.75%) were found inside the park. The invasion of P. juliflora towards the ANP is in the south direction, particularly along Sogedo site. The analysis from soil result indicates that except on some cations, mean values of the rest of the soil parameters under study were not significantly changed (p<0.05) in the presence and absence of P. juliflora. Hence, smaller individuals and lower densities of P. juliflora have lower (negligible) impacts on the associated plants and soils. This implies that the depressive effect of P. juliflora on the associated flora and soil depends on the density and size of P. juliflora.
URI: http://hdl.handle.net/123456789/2721
Appears in:Thesis - Environmental Sciences

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