Impact of Land Use on Vegetation Resources with Emphasis on Woody Vegetation in the Semi-Arid Area of Abala District, North Afar
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W IMPACT OF LAND USE ON VEGETATION RESOURCES WITH EMPHASIS ON WOODY VEGETATION IN THE SEMI-ARID AREA OF ABALA DISTRICT, NORTH AFAR, ETHIOPIA y BY DIRESS TSEGAYEALEMU B Sc Hons (ANIMA* SCIENCE) ALL MAYA UNIVERSITY OF AGRICULTURE, ETHIOPIA A THESIS SUBM1T1ED IN PARTIAL FULFILMENT OF Tl IF REQUIREMENT FOR THE DEGREE OF MASTER OF SCIENCE IN RANGE MANAGEMENT (RANGE ECOLOGY OPTION) JWVERSTTV OF * A,RO* UBFARV f . O. HAIROU DEPARTMENT OF RANGE MANAGEMENT. FACULTY OF AGRICULTURE. UNIVERSITY OF NAIROBI. KENYA 1 9 9 9 DECLARATION 1 hereby declare that this thesis is my original work and has not been submitted for a degree in any other university ________ Diress Tsegaye Alemu Date This thesis has been submitted with our approval as university supervisors 3 - ^ - o T - Dr. Kassim O. Farah Rate Senior lecturer. Department of Range Management University of Nairobi. Kenya. 0 V-/ d U g q - Mr. David M. Mbuvi Date Lecturer. Department of Range Management University of Nairobi. Kenya. i i DEDICATION This work is dedicated to my father who passed away while I was in Kenya for this study I le had the love to the family and good vision to all of us but departed from our midst at an early age. Fondly remembered and sadly missed by your family, relatives and friends Continue to enjoy eternal peace in the presence of God i l l * ACKNOWLEDGEMENTS This study was accomplished with support from many individuals and institutions Foremost I would like to express my thanks to the P1NEP Progiamme. a University of Nairobi/SARF.C Project based at the Department o f Range Management for the award of the scholarship 1 deeply express my appreciation to my supervisors. Dr Kassim O Farah and Mr David M Mbuvi. for their guidance, advice, and unhesitating support in completing this study 1 extend my appreciation to Dr Nashon K R Musimba for his valuable guidance and advice during the entire research process I also appreciate the assistance of Mr Awala Ochung who interpreted the aerial photographs with great care and patience Special thanks go to Mr Wellington Ekaya lot his valuable input in the entire research process and many insightful comments on the draft of this thesis Dr Nyariki was also very supportive in the preparation o f the thesis draft 1 am also thankful to the rest o f PINF.P staff. Irene Maeri. Abigael Kibisu and Fred Onvango, for their various contributions as a team or individually All the above individuals are based at the Department of Range Management. University of Nairobi. Kenya 1 am very gratefol to Dr Tcgcgne Teka, Regional Co-ordinator, the Dryland Husbandry Project (DiIP) based at OSSREA, Ethiopia, for his encouragement and support in identifying an area of study at a DHP site in Ethiopia I deeply express my heartfelt thanks to Dr Mitiku Haile, Dean Vlekellc University College and DHP National Co-ordinator. Ethiopia, for his guidance and advice during the fieldwork Special thanks go to Mr Mcrha Zcrabook for his unhesitating support during the entire fieldwork I also extend my thanks to other staff members of the college who helped me in one way or another. Mention is worthy of Mr Fasil and Solomon for their guidance and assistance during analysis of soil samples I am particularly grateful to Zone Two and Abala wervJa administrative bodies for granting me a research permit Lots of thanks go to my enumerators and translators (Mr Sumo Buksa. Aregav, Anbese. Indus, and Mohamed) and driver Mohammed Ibrahim for their tolerance to the hardships during the vegetation study and questionnaire survey I also appreciate Mr Lcgesse Zewdc. DHP site manager, for his encouragement and support I further appreciate Mr Abeje Habtamu and Abebe Ejigu for the accommodation given iv during the fieldwork in Mckcllc and Addis Ababa I am very thankful to Dr TafTese Mesfin. P1NEP National focal person, foi helping me to acquire this scholarship; without him 1 would not have reached this far l also exTend my thanks to Mr Sintavehu G/Mariam who helped me a lot to continue w ith my study A lot of thanks go to all my colleagues in the Ministry of Agriculture and Afar Region Agriculture Bureau (especially Mr Zcwdu Kebcde, Tekle Zeleke, Ahmed Mohanicd. Abdulrahim Ali. Dr Zeleke Dagnachew. Gebeyhu Afework. Abebe Reta, Suleman Mohamed and Mohamed Sulc) who have continuously encouraged me to continue with my study Special thanks go to my brother, Mr Marew Alemu. who provided encouragement and emotional support throughout all the years of my schooling Finally. I extend my thanks to all my friends for their continuous support and encouragement They include Mr Menker Tcdla. Abeje Habiamu. Assefa Assaye. Kumlachew Bayehu, Dr Asnakew Yigzaw, Aycnew Wudu. Abcbaw Iadessc. Bcrlianc Kassa. Tesfaye Alemu. Tibebu Dejen. Kahsay Negash Bobe and Yemisrach Menker v ABSTRACT This study aimed at investigating changes in vegetation resources with emphasis on the woody component in relation to land use changes (i e settlements, cultivation and grazing) It also made an anempt to understand the perception o f local communities as regards these changes in their land-based resources The study area was characterised by a semi-arid type of climate, where agropastoral production system was the predominant land use practice The methods employed were interpretation of aerial photographs taken at two points in time i e 1964 and 1994. field vegetation survey and analysis, interviews using a structured questionnaire, and informal and formal discussions Ih e results o f aerial photograph analyses indicate that conspicuous changes occurred in land use and vegetation types (physiognomically) ovci the 30-year penod between 196-1 and 1994 Changes in land use have apparently caused changes in vegetation structure These changes have resulted from introduction of settlements and subsequent practice* of flood recession cultivation Clearance of vegetation for cultivation in the tlood plains was found to be the major cause of depletion of vegetation resources and overgrazing of the uncultivated areas thereby leading to environmental deterioration The size of land under cultivation increased from 0.27% (97 5 ha) to 7 34% (2.605 ha) of the total area Settlement increased from 0 01% (5 ha) to 0 51% (180 ha) and vegetation cover decreased from 87 88% (31,252 5 ha) to 75.52%(26.787 5 ha) Field vegetation survey results showed that there was still a moderate woody vegetation cover dominated by Acacia etbaica wooded bushland in the uncultivated plain areas, the hills and ridges However, herbaceous cover was very poor and the understorey vegetation was mainly dominated by Euphorbia and Aloe species Woody vegetation identified and recorded included Acacia. Grewia. Balanites. SaivaJora. Cordia. Commiphora and other related genera A locational comparison of six selected woody species i c Acacia eihaita. Acacia mellifera, Acacia nubtea, Acacia loriilis. Grewia erythreu and SahxnJora persica showed no significant difference (P>0 05) among three study sites (Abala, Shugala and Murga) for species composition, percent crown cover, density and diversity Comparison vi among distances (in a 10 kilometre transect ran from each of the three selected land uses) within each site for percent cover and density also showed no significant difference (P>0 05). Comparison among species for each site and among distances for each species, however, showed a significant difference (P<0.05). Acacia elbaica had higher species composition, percent cover and density than other species in all the three study sites From the socio-economic survey, it was possible to retrieve information on characteristics of the indigenous Afars and settled Tigrians. woody vegetation use and perceptions of environmental degradation These communities arc already aware that settlement and cultivation in the area hampered the pastoral form o f life style and thus forced them to shirt to agricultural practices They acknowledged the vital role o f trees and shrubs since they provide a range of products and services in iheir daily life In sum, declining vegetation cover, formation of big gullies, declining water availability, reduction of wildlife numbers and species diversity arc the outcomes of recent settlement, cultivation and recurrent drought in the area Based on the findings of this study, recommended actions to mitigate and prevent negative environmental impacts include encouraging participation of local communities in the management of natural resources so as to utilise their indigenous technical knowledge, introducing soif and water conservation measures, protecting the existing grazing lands from encroaching cultivation, protecting and regenerating important woody species, and selective clearing and establishment of grazing reserves The study also recommends turther research on long-term vegetation monitoring. soil and vegetation relationships, etlinobotany/cthnovctcrinary practices, assessment of herbaceous and woody vegetation biomass, and evaluation of the nutritive value of browse species and crop residues as dry season feed for livestock v i i TABLE OF CONTENTS DECLARATION ................... " DEDICA'IION............... ............................................ ACKNOWLEDGEMENTS................- ............................. .................................. 'V ABSTRACT TABLE OF CONTENTS................................................................................................................'»»» LIST OF TABLES............................ X UNIVERSITY OF NAIROBIUST U OF FIGURES » LIST OF PL ATES UST OF APPENDICES..............-..................................................-