Diversity and Abundance of Bee Pollinators Visiting Hedgerow Plants
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DIVERSITY AND ABUNDANCE OF BEE POLLINATORS VISITING HEDGEROW PLANTS IN THE FARMLANDS BORDERING KAKAMEGA FOREST MWANGI, DAVID(KAMANDE (BSC. HORTICULTURE, EGERTON UNIVERSITY) A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF MASTER OF SCIENCE IN AGRICULTURAL RESOURCE MANAGEMENT OF THE UNIVERSITY OF NAIROBI. 2009 DECLARATION This thesis is my original work and has not been presented for a degree in any other university. Mwangi, David Kamande Signature Date j i i J L j a This thesis is been submitted for examination with our approval as university supervisors. 1. Prof. J. H. Nderitu Department of Plant Science and Crop Protection 2. Dr. M.W. Gikungu Zoology Department National Museums of Kenya Nairobi. Signature - --------- Date -- 6 3. Dr. M. Kraemer Faculty of Biology Bielefeld University Germany < 2 J August IS, 2009 Signature----- --------------------------- Date--------------------- DEDICATION To my wife Wambui and children Christine, Dennis and Kevin ACKNOWLEDGEMENT I would like to express my sincere gratitude to my employer, Ministry of Agriculture (Kenya) for granting me a two year study leave that made it possible for me to undertake the course. May I express my thanks and appreciation to Biota E.A. (E10) project, through the project leader Dr. Manfred Kraemer for accepting to support this study. I also wish to thank the University of Nairobi, especially the College of Agriculture and Veterinary Sciences, for giving me the opportunity to study in the University. Special thanks and appreciation go to my supervisors Prof. J. H. Nderitu, Dr. M. Gikungu and Dr. M. Kraemer for their support, guidance, patience and interest throughout the course of the study. My gratitude also go to Dr. M. Hagen, the Biota E10 project coordinator for her support and guidance, especially during data collection in Kakamega. I would also like to thank Dr. J. M. Kasina (KARI- NARL) who was always available for consultation. My special regards to my wife and children for their understanding, patience, prayers and encouragement during the course. Above all, I thank the Almighty God for giving me the necessary strength, knowledge and good health throughout the period of the study. ♦ IV TABLE OF CONTENTS 1. Title p ag e............................................................................................................................................. i 2. Declaration........................................................................................................................................... ii 3. Dedication........................................................................................................................................... iii 4. Acknowledgement.............................................................................................................................. iv 5. Table of contents..................................................................................................................................v 6. List of tables......................................................................................................................................viii 7. List of figures......................................................................................................................................ix 8. List of plates........................................................................................................................................ ix 9. List of acronyms and abbreviations...................................................................................................x 10. A bstract..............................................................................................................................................xi CHAPTER 1 ............................................................................................................................................1 1: INTRODUCTION................................................................................................................................1 1.1 Background Information.................................................................................................................. 1 1.2 Problem statement............................................................................................................................ 4 1.3 Justification........................................................................................................................................ 4 1.4 Objectives........................................................................................................................................... 6 1.5 Research questions............................................................................................................................ 7 1.6 References.......................................................................................................................................... 8 CHAPTER 2 .........................................................................................................................................10 2: LITERATURE REVIEW..................................................................................................................10 2.1 Pollination service..........................................................................................................................10 ; v 2.2 Economic value of pollination service.........................................................................................10 2.3 Role of pollinators in Agriculture and the ecosystem............................................................... 11 2.4 Bees as pollinators of agricultural crops..................................................................................... 13 2.5 Land management for bee conservation...................................................................................... 13 2.6 Hedgerows and bees....................................................................................................................... 14 2.7 References...................... 16 CHAPTER 3 ..........................................................................................................................................19 3: DIVERSITY AND ABUNDANCE OF BEE SPECIES IN THE MAJOR BEE RESOURCE PLANTS IN THE FARMLAND HEDGEROWS ADJACENT TO KAKAMEGA FOREST.............................................................................................................................................19 3.1 Introduction...................................................................................................................................... 19 3.2 Materials and m ethods....................................................................................................................20 3.2.1 Study area......................................................................................................................................20 3.2.2 Sampling................................. 21 3.3 Results...............................................................................................................................................23 3.3.1 Bee diversity and abundance in the hedgerows......................................................................23 3.3.3 Effect of land use on the number of bee species and individuals.......................................... 29 3.3.4 Bee visitation on the hedgerow flowers.................................................................................... 31 3.3.5 Effect of the number of hedgerow flowers on bees................................................................. 37 3.3.6 Effect of hedgerow characteristics and weather parameters on bees....................................38 3.4 Discussion........................................................................................................................................ 39 3.5 References....................................................................................................................................... 42 ; vi CHAPTER 4 44 4: GENERAL DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS....................44 4.1 Discussion....................................................................................................................................... 44 4.2 Conclusion....................................................................................................................................... 45 4.3 Recommendations..........................................................................................................................46 4.4 References....................................................................................................................................... 47 \ / ♦ vii LIST OF TABLES Table 1: Degree of dependence of selected crops on insect pollination....................................... 12 Table 2: A list of the bee species in each family in the hedgerows...............................................23 Table 3: Frequency of occurrence and the number of individuals of the various bee categories in the hedgerows for the six months.....................................................................................26 Table 4: Relationship between the number of hedgerow flowers and the number of bee individuals on the hedgerows................................................................................................ 28 Table 5: Mean number of bee individuals on hedgerow flowers under different land use categories.................................................................................................................................30