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Bryophytes and Tracheophytes Along an Altitudinal Gradient Using Narumoru Tract of the Western Slope of Mt

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Bryophytes and Tracheophytes Along an Altitudinal Gradient Using Narumoru Tract of the Western Slope of Mt THE DISTRIBUTION OF TWO MAJOR PLANT GROUPS (BRYOPHYTES AND TRACHEOPHYTES) ALONG AN ALTITUDINAL GRADIENT ON NARO MORU TRACK, MOUNT KENYA. BY WEKESA SARAH NEKESA, B.Ed. (Science) Egerton A thesis submitted in partial fulfillment of the degree of Master of Science in Plant Taxonomy and Economic Botany in the School of Biological Sciences University of Nairobi 2015 i DECLARATION I certify that this thesis is my original work and has not been presented in any other University. Sign…………………………… ………………………… Sarah Nekesa Wekesa Date This thesis has been submitted for examination with our approval as University Supervisors: Sign………………………… Date …………………… Dr. C.W. Lukhoba School of Biological Sciences University of Nairobi. Sign ………………………… Date…………………… Prof. N. Gichuki School of Biological Sciences The University of Nairobi, Kenya ii DEDICATION This work is dedicated to my dear husband George, and children David, Yang, Cissie, and Gorrel. And To the nation and people of Kenya; to whom the Almighty GOD bestowed the responsibility to conserve its splendor. iii ACKNOWLEDGEMENT I wish to express my deep appreciation and very sincere gratitude to my supervisors Dr. Catherine W. Lukhoba for encouraging me to study at the department and having introduced me for the first time to mountain climbing and Prof. Nathan Gichuki for his untiring commitment and for giving me endless advice all throughout the project duration. Many thanks go to the University of Nairobi staff and students for their continued support in my research work. I am particularly grateful to Dr. S. M. Chuah for showing me how to identify bryological specimens. The following technical staff from University of Nairobi is particularly recognized for their assistance in field work and plant identification: Mr. Martin Wafula Kisyelo, Mr. Herbert Khayo, Mr. Patrick Mutiso, Mr. William Chebii and Mr. Simon Mathenge. I wish to also thank my husband and friend George, for shouldering the immense expenses of this project. Last but not least, I cannot forget to remember my David, Yang, Cissie and Gee for their continued support and perseverance from the beginning to the end of this project. To all I pray that GOD will mightily once again use you in a special way to help others too. AND TO MY GOD, I AM REALLY GRATEFUL FOR GIVING ME STRENGTH AND COURAGE TO ENDURE, THANK YOU LORD, AMEN. iv ABSTRACT Tropical mountain forests are known as the cradle of flowering plants and have many archaic angiosperm taxa. However processes of climate change and human activities have resulted in massive degradation and loss of mountain biodiversity. In Mt. Kenya, human activities have caused the shifting of the forest base margin to higher altitudes, increased soil erosion with resultant increase in sedimentation of wetlands, rivers and water storage dams down steam posing serious and economic consequences. The presence of cryptogams are known to contribute to the good health of mountain ecosystems, however their composition, abundance and distribution in the face of the ongoing forest destruction in Mt Kenya is not clear. The aim of this study was therefore, to establish the taxonomic and ecological relationship between one group of cryptogams- the bryophytes and tracheophytes along an altitudinal gradient using Narumoru tract of the western slope of Mt. Kenya. Plants were sampled at an interval of 200m from 2400 to 4800m. The higher plants were sampled along a 50 m transect using 10m by 10 m plots while the bryophytes were sampled using 10 x5cm quadrats of the same plots where higher plants were collected. Fine-scale variations in bryophyte communities were investigated in nine microhabitats including the soil surface, humus layer, decaying lignin, stem trunks, rachises, rocks and water edges. All the specimens collected were identified in the field and later confirmed at the University of Nairobi (NAI) and National Museums of Kenya (EA) herbaria. Data analysis and descriptive and inferential measures of species diversity were done using SPSS computer program. The results showed that bryophytes had the highest diversity (50.6%) followed by angiosperms (47.3%), while gymnosperms had the lowest (1.3%). There was a general decrease in the plant species diversity from 2400m to 4600m asl, the optimum levels being at 2400 and 3000m asl (each containing over 350 species). At least five microhabitats were identified with the most diverse bryophytes being the humicolous and corticolous types (80%) while the least was aquatic (0.001%). It is hoped that data accrued from this study will aid in the conservation of the Mt Kenya mountain flora. The aim of this study was to establish the taxonomic and ecological relationship between bryophytes and tracheophytes along western slope of Mt. Kenya and this has been determined whereby the study revealed that NMT of Mt. Kenya harbors a high diversity of bryophytes and tracheophytes 81 and 83 in percentage it is 50 and 49 respectively. The study has also demonstrated that the diversity and distribution of bryophytes and the tracheophytes is influenced firstly by altitude and secondly by the microhabitats provided by natural features such as bogs, rocks and the tracheophytes themselves. Therefore, the taxonomic information of the less studied and less appreciated groups is essential in laying down the strategies to conserve Mt. Kenya. Key words: Tracheophytes, Bryophytes, Diversity, Distribution, Microhabitat, Angiosperms, Pteridophytes, Gymnosperms. v TABLE OF CONTENTS DECLARATION ...................................................................................................................... ii DEDICATION ........................................................................................................................ iii ACKNOWLEDGEMENT ...................................................................................................... iv TABLE OF CONTENTS ........................................................................................................ vi LIST OF FIGURES ..................................................................................................................x CHAPTER ONE .......................................................................................................................1 INTRODUCTION .....................................................................................................................1 1.1 Significance of Mountain Ecosystem in Africa ........................................................................... 1 1.2 Mountains as conservation areas for water and soil ................................................................... 4 1.3 Mountain effects on climatic zonation ......................................................................................... 6 1.4 Mountains as recreation areas for urbanized societies ............................................................... 7 1.5 Mountain forests are a wealth of biodiversity ............................................................................. 8 1.6 Environmental problems affecting mountain ecosystems......................................................... 10 1.7 Problem statement ..................................................................................................................... 11 1.8 Research aims and objectives .................................................................................................... 12 1.8.1 General aim ......................................................................................................................... 12 1.8.2 Specific objectives ............................................................................................................... 12 CHAPTER TWO .................................................................................................................... 13 LITERATURE REVIEW ....................................................................................................... 13 2.1 Characteristics of tropical mountains ....................................................................................... 13 2.2 Geological and geographical factors influencing plant distribution ......................................... 14 2.3 Environmental factors influencing plant distribution and diversity ........................................ 15 2.4 General distribution of vegetation on Mount Kenya ................................................................ 16 vi 2.4.1 State of knowledge of bryophytes ........................................................................................... 18 2.4.2 Pteridophytes ....................................................................................................................... 20 2.4.3 Gymnosperms...................................................................................................................... 21 2.4.4 Angiosperms ........................................................................................................................ 21 2.5 Conservation strategy of Mount Kenya .................................................................................... 22 2.6 Social-Economic importance of Mt Kenya ................................................................................ 23 METHODOLOGY .................................................................................................................. 24 Study Area. .............................................................................................................................. 24 Location and structure
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