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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/3024

Advisors: Dr. Mekuria Argaw (Ph.D.)
Dr. Gemedo Dalle (Ph.D.)
Keywords: Yangudi-Rassa, floristic composition, Structure
plant community
Copyright: Feb-2010
Date Added: 11-May-2012
Publisher: AAU
Abstract: This study was carried out at Yangudi-Rassa National Park, northeastern Ethiopia with the aim of compiling floristic composition, vegetation structure and to identify community types. A total of 90 relevés, 20 m x 20 m at 200 m intervals within six transect line were laid to collect the data on cover-abundance (for woody species and herbs), DBH, height, density, seedling and sapling count (for woody species only). The data on herbaceous species were collected from five, 1 m x 1 m subplots laid at four corners each and one at the centre of the large relevé. Two Way Indicator Species Analysis (TWINSPAN) was used to classify the vegetation community types. The importance value index (IVI) of dominant woody species was estimated and finally, the Shannon- Weiner diversity and evenness indices were calculated. A total of 70 plant specimens belonging to 25 families and 55 genera were identified of which 58.6% were herbs other than grasses, 12.9% were shrubs, 12.9% were grasses, 11.4% were tree or shrub and 4.3% were trees. Two Way Indicator Species Analysis (TWINSPAN) classified vegetation of the Yangudi-Rassa National Park into seven community types: (I) Cenchrus pennisetiformis - Commelina imberbis type; ( II) Chloris virgata - Aristida adscensionis type; (III) Heliotropium strigosum - Convolvulus farinosus type; (IV) Caralluma speciosa - Grewia villosa type; (V) Dichrostachys cinerea - Senna italica type; (VI) Heliotropium steudneri - Dichrostachys cinerea type and (VII) Ziziphus spina-christi - Cleome scaposa type. The Density of woody species with DBH > 2.5cm (ca. 427/ha), basal area (ca. 3.12 m2/ha), frequency of all the tree species (241/ha) and then among the woody plants with higher value of the importance value index (IVI) were Acacia mellifera, Cadaba rotundifolia, Acacia oliveri, and Grewia tenax. Finally, the result of Shannon-Weiner diversity and evenness indices showed that community type VII was the most diverse and had the highest species richness. On other hand, Community type VI had the least diverse and least number of species with least even distribution when it compared with the other communities. The study indicated that the population structure of the most woody plant species in Yangudi-Rassa National Park is in a good state of regeneration but poor recruitment level and there is a need to further investigate on soils and ethno-botanical studies
URI: http://hdl.handle.net/123456789/3024
Appears in:Thesis - Environmental Sciences

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