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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/14942
Title: An Ecological Study of the Forest Vegetation of Southwestern Ethiopia
???metadata.dc.contributor.*???: Dr. Tamrat Bekele
Yeshitela, Kumelachew
Issue Date: Jun-1997
Publisher: Addis Ababa University
Abstract: The floristic composition and structure of the forest vegetation of southwestern Ethiopia between altitudes 1050 to 2500 m are described. Sample plots of 30 m x 30 m were taken for woody plants and 2 m x 2 m for herbaceous and bamboo plants. A total of 101 sample plots were analyzed. The cover-abundance values for trees, shrubs and herbs within the sample plots were estimated. All trees and shrubs with diameter at breast height (DBH), i.e, 1.3 m of≥ 2 cm were measured for height and diameter. The leaf size of all tree species with heights ≥ 6 m was measured. The presence of epiphytes on each woody individuals and the presence of woody climbers (lianas) in the sample plot was noted. Altitude, slope, and exposure were measured and soil samples from surface and sub-surface were taken and analyzed for pH, electrical conductivity, soil colour, texture, organic carbon, total nitrogen, available phosphorus, exchangeable bases, and cation exchange capacity. A total of 139 species of vascular plants, 15 species of vascular epiphytes, and 12 species of woody climbers (lianas) were recorded. Average linkage clustering procedure was followed to classify the vegetation data and 9 clusters were recognized and the clusters were identified as local plant community types and given names after one or two dominating and/or characteristic species. The community types are: Arundinaria alpina, -Manilikara butugi-Coffea arabica, Syzygium guineenus-Maytenus gracilipes, llex mitis-Galiniera saxifraga, Celtis africana-Dracaena afromontana, Allophylus abyssinicus-Justicia schimperiana, Aningeria adolfi:friederici-Chionanthes mildbraedii, Syzygium guineense-Dracaena afromontana, and Olea welwitschii-Chionanthes mildbraedii. Analysis of variance (ANOVA) was performed to see if there is any significant variation among the community types with respect to any one environmental parameter. The result obtained shows that the community types significantly vary for all the environmental parameters except for slope, exposure, exchangeable sodium and potassium, cation exchange capacity and available phosphorus for subsoil (20-60 cm). Altitude is the environmental parameter that differentiate most of the community types. Some of the environmental perimeter are significantly correlated. The structural analysis of the community types showed that the density of trees in the > 10 cm DBH class is significantly higher than density in the > 20 cm DBH class. Forty-seven per cent of the trees in Manilikara butugi­Coffea arabica community type, and more than 60% of the trees in the remaining types belong to the lowest diameter class (5-20 cm). More than 50% of the trees in Manilikara butugi-Coffea arabica and Syzygium guineense-Maytenus gracilipes community type and over 70% of the trees in the remaining community types fall into the lowest height classes (6-9 & 9-12 m). Mosses are the most abundant epiphytes in all community types and Landolphia buchananni is the abundant liana in all community types except in Allophylus abyssinicus-Justicia schimperiana type. The predominant leaf size class in all community types is mesophyll (4500-18,225 mm2), while microphylls (225-2025 mm2), notophylls (2025-4500 mm2), macrophylls (18,225-164,025 mm2), and megaphylls (> 164,025 mm2) leaf sizes are shared by less than 20% of the species. Only mesophylls are present in Arundinaria alpina community type.
Description: A Thesis Submitted in (Part) Fulfillment for the Degree of Master of Science in Biology in Addis Ababa University
URI: http://hdl.handle.net/123456789/14942
Appears in Collections:Thesis - Biology

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