The Ecology of the Alpine Zone of Mount Kenya by M. J. Coe VIII and 136 pages with 20 figs., frontispiece and 24 plates.

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1 The Ecology of the Alpine Zone of Mount Kenya by M. J. Coe VIII and 136 pages with 20 figs., frontispiece and 24 plates. A brief account of the history of the mountain's exploration is followed by an outline of the physiography, geology and glacial geology, particularly where they are relevant to the study of the ecology of the Alpine Zone. After a short description of the Ericaceous Zone, the main plant communities of the Alpine Zone are described. The climate in conjunction with the mountain's glacially eroded surface are shown to be the primary soil-forming and distributing factors, wh ile the marked diurnal temperature fluctuations are largely responsible for the great dominance of rosette forms amongst Alpine plant communities. The presence of a d istinct Nival Zone close to the glaciers presents an ideal site for the study of the primary stages of plant colonisation and soil formation. The vertebrate fauna is shown to exh ibit a remarkable spectrum of food preference and habitat. The monograph, illustrated by 20 line drawings and 24 plates. ends with a bibliography of 180 references and an index. cover design by Max Velthuijs

2 THE ECOLOGY OF THE ALPINE ZONE OF MOUNT KENYA

3 MONOGRAPHIAE BIOLOGICAE EDITOR P. VAN OYE Gent VOLUMEN XVII DR. W. JUNK PUBLISHERS - THE HAGUE

4 THE ECOLOGY OF THE ALPINE ZONE OF MOUNT KENYA by MALCOLM JAMES COE DR. W. JUNK PUBLISHERS - THE HAGUE

6 The main peaks of Mount Kenya. The highest points Batian and Nelion are in the centre holding the Diamond glacier between then. The Darwin glacier with its recent moraines are directly below the main peaks and the Heim and Forel Glaciers on the left.

7 v LIST OF CONTENTS INTRODUCTION. PHYSIOGRAPHY GEOLOGY... GLACIAL GEOLOGY. VEGETATIO~ ZONES AND COMMUNITIES. 1. Ericaceous (lhoarland) Zane... (a) Damp boggy ground (b) Raised rocky ridges, or old weathered moraines (c) Stream courses.. 2. The Alpille Zone The Lower A lpine Zone (a) Flat or gently sloping ground, usually wet (b) '''eathered and eroded ridge tops 4. The Upper Alpine Zone (a) Valley \yalls. (b) Valley floors.. (c) Ridge tops... (d) Lakes and Tarns 5. The Nival Zone THE ALPIXE CLIJ\IATE 1. Temperature.. 2. Rail1fall Wind Climate and the Alpine Vegetation. THE DEVELOPJ\1ENT A~D DISTRIBUTION OF ALPINE SOILS 1. Soil generation The differentiation of Alpine soil habitats.. 3. The Structure and Chemistry of Alpine soils. COLONISATION IN THE ALPINE ZONE Primary colonisation in the Alpine Zone.. (a) Colonisation of the Tyndall Glacier moraine (b) Colonisation of the Lewis Glacier moraine. (c) Proglacial Tarns.... (d) Dating moraine deposits. 2. Other Phases of Colonisation. BIOTIC FACTORS IN THE ALPINE ZONE. 1. Relations between animals, vegetation and habitats 2. Herbivores and their relation to vegetation. (a) Population size and control. (b) Breeding as a control factor DISCUSSION SUMMARY AND COXCLUSIONS BIBLIOGRAPHY INDEX PAGE :

8 VI The monograph is based, primarily, on field work carried out on :Mount Kenya between December, 1957 and January, 1963, and was used in part as a Ph. D. thesis of the University of London. A brief account of the history of the mountain's exploration is followed by an outline of the physiography, geology and glacial geology, particularly where they are relevant to the study of the ecology of the Alpine Zone. Some confusion has arisen over the delimitation of Alpine vegetation zones and these are discussed in the light of the Author's observations. Following a brief description of the Ericaceous Zone, the main plant communities of the Alpine Zone are described and are found to be more closely related to the mountain's physiography than to factors of altitude. The climate in conjunction with the mountain's glacially eroded surface are shown to be the primary soil-forming and distributing factors, while the marked diurnal temperature fluctuations are largely responsible for the great predominance of rosette growth forms amongst Alpine plant communities. Frost soil phenomena are also shown to be of great importance in the establishment of plant communities. The presence of a distinct Nival Zone close to the glaciers presents an ideal site for the study of the primary stages of plant colonisation and soil formation. It is shown that the vegetation in this region supports glacio-geological opinion that Mount Kenya's glaciers have undergone a period of advance in recent time. Other stages of vegetation development at lower altitudes are also described. The vertebrate fauna is shown to exhibit a remarkable spectrum of food preference and habitat which, together with an apparent reduction of the number of young produced, is an important factor in preserving the essentially slow-growing Alpine vegetation. The features of major importance are discussed and suggestions are made for a further programme of work in the Alpine Zone of Mount Kenya.

9 VII ACKNOWLEDGEMENTS The work described here was started when the Author was included in the International Geophysical Year Mount Kenya Expedition under the leadership of Professor I.S. LOUPEKINE. I am grateful to the leader of this expedition and to other members who stimulated my interests in this work, and offered their companionship on numerous long and often uncomfortable safaris on the mountain. I would like to express my thanks to Dr. Olov HEDBERG, of the Department of Systematic Botany, Uppsala, Sweden, for his advice and help in identifying my earlier plant collections; also to Professor Robert FRIES of Stockholm, for supplying me with reprints of his valuable papers on this and other East African mountains. In the preparation of this manuscript I wish to express my gratitude to the late Professor \V. H. PEARSALL, Dr. George SALT, and Professor Carl TROLL for their help and encouragement. In Nairobi I have been helped in many ways by Dr. B. VERD COURT and Miss D. NAPPER of the East African Herbarium, by Bob CARCASSON and John \VILLIAMS of the Coryndon Museum, and by my colleagues, John SALE in the Department of Zoology and Dr. W. T. W. MORGAN, Head of the Department of Geography in the University College, Nairobi with many useful discussions and criticisms. I am also indebted to the following members of Government Departments in Kenya who have helped by supplying unpublished information: Dick JONES of the Kenya Hydrology Department for information concerning the rainfall of Mount Kenya; the Director, Kenya Meteorological Department for valuable data on temperatures; Frank CHARNLEY of the Kenya Survey Department for help with maps; the Director of Hunting Clan Aero Surveys for permission to use their aerial photographs of the mountain; the Directorate of Overseas Surveys for supplying lay-downs of the 1948 R.A.F. aerial photographs; the Soil Chemists of the Scott Agricultural Laboratories for help with Alpine soils; and my very good friend, Brian BAKER, for his invaluable help with geological and related matters. I wish to express my thanks to the University College for grants made to assist with porter and other expenses when visiting the mountain. Among many other colleagues who have assisted me in various ways I should like to mention Dr. G. S. NELSON, of the London School of Hygiene and Tropical Medicine, and Dr. Heinz LOEFFLER, of Vienna University, whose council and advice have been of great use and who shared my enthusiasm for this wonderful mountain. I am grateful to Pierre LOUIS and Mr. DHANJAL, of the University

10 VIII College, for their assistance in the preparation of plates, also to Mr. D'SOUZA for his careful draftsmanship in improving some of my maps. Last, but by no means least, I would like to thank Mrs. DEARDEX for her care in typing the manuscript, and my wife, Unity, for her encouragement in preparing the final draft for this manuscript. All field work conducted on Mount Kenya has been carried out with the kind permission of the Director of the Kenya National Parks, Mr MERVYN COWIE, and the ever willing cooperation of his Mountain Park Wardens, JOHN ALExA::-mER and BILL WOODLEY.

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