AAU-ETD AAU-ETD
 

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/123456789/2119

Title: Area closure as a Strategy of Biodiversity Conservation and Degraded Land Rehabilitation: The Cases of Gubo and Ninikotto, North Wello
Authors: Wendwessen, Girmay Werku
Advisors: Dr. Mekuria Argaw
Keywords: State-and-transition model
Restoration
Soil seed bank
Vegetation diversity
Area closure
Copyright: Jan-2009
Date Added: 3-May-2012
Abstract: The study was conducted in Habru Wereda, North wello to assess the role of area closures in the restoration of plant species diversity, soil seed bank density, and soil quality improvement. Data was collected from three area closure sites of 10yrs, 5yrs, and 3yrs since closure (hereafter called age), and adjacent open-grazed lands, considerd as controls using stratified and systematic sampling procedures. Vegetation, soil seed bank, physical and chemical properties of soil were analyzed for each management types (enclosures versus open-grazed). Specific state and transition model has been employed to determine the change in vegetation diversity. The result indicated that in general, management and age influenced the vegetation species richness and diversity, Soil seed bank (SSB) density, and soil organic matter (SOM) content. Sorensen’s similarity coefficient (SSC) ranging from 0.20 to 0.42 indicated lower similarity between each area closure and respective open-grazed land. Restoration of woody plant species richness and diversity increases with age, but the herbaceous species diversity declined after three years. A total of 105 plant species belonging to 78 genera and 39 families were identified. Herbaceous, shrubs and tree species accounted for 48.54%, 34.95%, and 17.47%, respectively. Eighteen families were recorded in both area closure and open-grazed lands. Asteraceae, Fabaceae, Euphorbiaceae, Poaceae and Solanaceae were the most dominant families in the area closures. Comparatively, in the open-grazed land, Asteraceae, Fabaceae and Solanaceae were dominant. In both sites, Asteraceae and Fabaceae were dominant. Three plant community types were identified and described. The Shannon-wiener diversity index was greater for the 10yrs old area closure and lowest for the open- grazed land. SSB density for both woody and herbaceous species was higher at the first 0-3cm depth and decreases down to 9 cm and grass seed dominated the seed bank in both management types and increases with age in area closures. The Specific state and transition model revealed five states and eight transitions that portray restoration and degradation phases along the recovery pathway.Management and age significantly (p<0.05) affected SOM in area closures and the improvement in the area closures over their corresponding open-grazed land was 50.14%, 43.66%, and 56.18% for the 10yrs, 5yrs, 3ysr area closures respectively. There was no significant difference in soil pH, Av.P, Av.K and CEC between the two management and among the different age of area closure. SOM exhibited an increasing trend with the age of area closure. The study has indicated the potential of area closures for recovery of vegetation diversity in all three sites, suggesting that if proper conservation measures are taken, plant biodiversity will sustainabily be conserved. However, long-term monitoring will be required to gain an informed understanding of the roles of management types and age, in the restoration of plant biodiversity in the study area. .
URI: http://hdl.handle.net/123456789/2119
Appears in:Thesis - Environmental Sciences

Files in This Item:

File Description SizeFormat
252.37 MBAdobe PDFView/Open

Items in the AAUL Digital Library are protected by copyright, with all rights reserved, unless otherwise indicated.

 

  Last updated: May 2010. Copyright © Addis Ababa University Libraries - Feedback