|
Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
Faculty of Science >
Thesis - Environmental Sciences >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/123456789/2137
|
| Title: | Bush Encroachment and its Impacts on Plant Biodiversity in the Borana Rangelands |
| Authors: | Adisu, Abebe |
| Advisors: | Dr. Mekuria Aregaw
Dr. Taye Tesema |
| Copyright: | Nov-2009 |
| Date Added: | 3-May-2012 |
| Abstract: | Abstract
Until few decades ago the Borana rangeland was considered as one of the finest
grazing areas in East Africa. However, the pastoral system has recently shown
symptoms of destabilization because of the shift in the natural balance between
trees and grasses, and bush-tree cover has become dominant in the rangeland. In
order to assess the major encroaching woody plant species and their advancement
under three land use units (Kalo, Worra & Foora); the impact on plant biodiversity; as
well as possible causes of the encroachment and their challenges to the pastoral
community; a comprehensive vegetation and household survey was conducted. The
results of the study revealed that the density of woody species in the study area is
4185 ha ̄ ¹, which is far beyond the critical limit. Species such as Acacia
drepanolobium, A. mellifera, A. bussi, A. bresvispica, and A. senegal were found to
be the major encroaching species. The mean density of total woody species
significantly differed across the land use units (P < 0.05). Relatively higher densities
of woody plants occurred at Kalos that might associate with reduced grazing
pressure in Kalos compared to other land use units provide suitable environment for
seeds to germinate. Diversity of herbaceous grass species negatively correlated with
woody density(r=-0.520, p<0.01). The pastoralists asserted that encroachment of
woody species to their prime grazing land has been the major challenge to their
livelihoods. The pastoralists also perceived that restriction of indigenous rangeland
management system and climate change in terms of erratic rainfall and drought
were among the main factors that caused woody plant encroachment. Thus
interventions in the range management need to be in consultation with local
communities and in harmony with traditional systems.
Key words: Biodiversity, bush encroachment, Borana pastoralists, density, land use
units |
| URI: | http://hdl.handle.net/123456789/2137 |
| Appears in: | Thesis - Environmental Sciences
|
Items in the AAUL Digital Library are protected by copyright, with all rights reserved, unless otherwise indicated.
|
