EFFECTS of Bischofia Javanica (BISHOPWOOD) on STAND STRUCTURE and SPECIES DIVERSITY in NATURAL and PLANTED VEGETATION TYPES in KAKAMEGA FOREST, KENYA
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EFFECTS OF Bischofia javanica (BISHOPWOOD) ON STAND STRUCTURE AND SPECIES DIVERSITY IN NATURAL AND PLANTED VEGETATION TYPES IN KAKAMEGA FOREST, KENYA BY BRIMAS WASWA KITUYI (BSc. AGRIC. EDUC. AND EXENSION) I56/CE/28406/2013 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE (PLANT ECOLOGY) IN THE SCHOOL OF PURE AND APPLIED SCIENCES OF KENYATTA UNIVERSITY SEPTEMBER, 2018 ii iii DEDICATION To my parents, my wife Linda and children – Lincoln, Brianna Leticia and Liam Bransyn for their unwavering support and encouragement throughout my studies. iv ACKNOWLEDGEMENT I express my gratitude to the following for providing me with the opportunity and inspiration to embark on and complete this work. Firstly, I thank the almighty God for giving me the strength, health, wisdom and a sound mind to be able to pursue my studies. Secondly, my sincere appreciation goes to my supervisors – Dr. Emily Wabuyele of Kenyatta University Department of Plant Sciences and Dr. John Otuoma of the Kenya Forest Research Institute (KEFRI) for their guidance and oversight of the research. Their kind and meticulous input gave me the motivation and courage to forge ahead and complete this task. Finally, I thank Mr. Joel Mbogani, a member from the community around Kakamega forest for helping in providing local names of tree species and directing me to study sites. v TABLE OF CONTENTS DECLARATION ......................................................................................... Error! Bookmark not defined. DEDICATION ..................................................................................................................... ii ACKNOWLEDGEMENT ................................................................................................... iv TABLE OF CONTENTS ..................................................................................................... v LIST OF FIGURES ............................................................................................................ viii LIST OF TABLES .............................................................................................................. ix LIST OF APPENDICES ...................................................................................................... x LIST OF ABBREVIATIONS ............................................................................................. xi ABSTRACT ........................................................................................................................ xii 1. INTRODUCTION ............................................................................................................ 1 1.1 Background Information .............................................................................................. 1 1.2 Statement of the problem and justification ..................................................................... 2 1.3 Objectives of the study ................................................................................................. 3 1.3.1 General objective ......................................................................................................... 3 1.3.1 Specific objectives ....................................................................................................... 3 1.4 Hypotheses ...................................................................................................................... 4 1.5 Significance of the study ................................................................................................ 4 2. LITERATURE REVIEW ................................................................................................. 5 2.1 Invasive plant species ..................................................................................................... 5 2.2 Ecological characteristics of an invasive species ........................................................ 5 2.3 Effects of invasive plant species on plant community structure .................................. 6 2.4 Distribution and invasive history of B. javanica .......................................................... 6 vi 2.5 Description of B. javanica ........................................................................................... 8 3. MATERIALS AND METHODS .................................................................................... 10 3.1 Study area ...................................................................................................................... 10 3.1.1 Location ...................................................................................................................... 11 3.1.2 Biodiversity and Economic Activities ........................................................................ 11 3.1.3 Forest blocks and Vegetation types in the study area ................................................. 12 3.2 Experimental Design ..................................................................................................... 13 3.2.1 Sample size ................................................................................................................. 14 3.2.2 Layout of plots ............................................................................................................ 15 3.3 Data collection ............................................................................................................... 16 3.4 Data analysis .................................................................................................................. 16 4.0 RESULTS AND DISCUSSION .................................................................................... 19 4.1 RESULTS ...................................................................................................................... 19 4.1.1 Occurrence, relative abundance and dominance of B. javanica ................................. 19 4.1.2 Relative abundance of B. javanica ............................................................................. 20 4.1.3 Relative basal area of B. javanica. ............................................................................. 21 4.1.4 Importance value index of B. javanica ....................................................................... 22 4.1.5 Stand structure and recruitment pattern of B. javanica .............................................. 23 4.1.5.1 B. javanica’s contribution to stem density in other vegetation types. ..................... 23 4.1.5.2 Recruitment and distribution of B. javanica in DBH size-classes .......................... 24 4.1.6 Effect of B. javanica recruitment on species diversity ............................................... 30 4.1.7 Effect of B. javanica recruitment on species evenness .............................................. 31 4.2 Discussion ...................................................................................................................... 32 4.2.1 Occurrence of B. javanica in vegetation types. .......................................................... 32 4.2.2 Relative abundance of B. javanica ............................................................................. 33 vii 4.2.3 Relative dominance of B. javanica ............................................................................. 34 4.2.4 Stand structure and recruitment pattern of B. javanica .............................................. 36 4.2.5 Effect of B. javanica recruitment on woody species diversity and evenness ............. 38 5.0 CONCLUSION AND RECOMMENDATIONS .......................................................... 40 5.1 Conclusion ..................................................................................................................... 40 5.2 Recommendations ......................................................................................................... 40 REFERENCES .................................................................................................................... 42 APPENDICES ..................................................................................................................... 46 viii LIST OF FIGURES Figure 2.1. B. javanica Blume at different stages of growth ............................................... 9 Figure 3.1: Image of Kakamega forest blocks indicating distribution of vegetation types . ............................................................................................................. 10 Figure 3.2: Three fractional forest design nesting sub-bocks in main blocks .................. 13 Figure 3.3: Rectangular sampling plot illustrating stratification of sampling units within the Sub-Blocks. .............................................................................................. 14 Figure 3.4: Illustration of plot layouts that were used for assessment (Not drawn to scale) .............................................................................................................. 15 Figure 4.1: Occurrence of B. javanica in vegetation types of Kakamega forest .............. 20 Figure 4.2: A comparison of woody seedling densities in different vegetation types of Kakamega forest. ........................................................................................... 25 Figure 4.3: A comparison of woody stem density of tree species in the 0.1–10.0 cm DBH size-class of different vegetation types in Kakamega forest. ............... 26 Figure 4.4: A comparison of tree species in the 10.1 and above DBH range in Kakamega forest. ..........................................................................................