BEHAVIOURAL ECOLOGY OF THE SILVER LEAF MONKEY, Trachypithecus auratus sondaicus, IN THE PANGANDARAN NATURE RESERVE, WEST JAVA, INDONESIA by KAREN MARGARETHA KOOL A dissertation submitted to the University of New South Wales for the degree of Doctor of Philosophy School of Biological Science University of New South Wales Sydney, New South Wales Australia March, 1989 SR PT02 Form 2 RETENTION THE UNIVERSITY OF NEW SOUTH WALES DECLARATION RELATING TO DISPOSITION OF PROJECT REPORT/THESIS This is to certify that I . .1�9.-.C:eo...... MQ;.r.tQ.J:£'\hP..-. .. .J�l.... being a candidate for the degree of 1)!=>.d:o.r.--.of.-.Y.hSos.Of.hy .. am fully aware of the policy of the University relating to the retention and use of higherdegree project reports and theses, namely that the University retains the copies submitted for examination and is free to allow them to be consulted or borrowed. Subject to the provisions of the Copyright Act, 1968, the University may issue a project report or thesis in whole or in part, in photostat or microfilm or other copying medium. In the light of these provisions I declare that I wish to retain my full privileges of copyright and request that neither the whole nor any portion of my project report/thesis be published by the University Librarian and that the Librarian may not authorise the publication of the whole or any part of it, and that I further declare that thispreservation of my copyright privileges shall lapse from the ... :fit.�t ............ day of ...3.o.n ....... 9..r: { ............... 19.�.<:\.................. unless it shall previously have been extended or revoked in writing over my hand. I also authorise the publication by University Microfilms of a 350 word abstract in Dissertation Abstracts International ( applicable to doctorates only). Signature ... ::.:.,.,.,-· ....... Witness... ..... Date .... :1-.o... M.<\£.ch.... i.. <). i.9 ......... Trachypithecus auratus sondaicus iii CERTIFICATE OF ORIGINALITY I hereby declare that this thesis is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another _person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of a university or other institute of higher learning, except where due acknowledgement is made in the text of the thesis. Karen Kool March, 1989 iv ACKNOWLEDGEMENTS This study owes its inception to two people. Dr J. MacKinnon suggested the silver leaf monkey Trachypithecus auratus as a suitable species for study and recommended Pangandaran as a study area. Dr D.B. Croft indicated a willingness (where others hesitated) to supervise a student planning to conduct research overseas. I am extremely grateful to both these people for encouraging me to pursue a long-held ambition. Dr C.P. Groves also provided invaluable advice and encouragement at the outset and provided me with an extensive reading list so that I could become acquainted with primate ecology. Dr Y. Ruhiyat showed me the first T. auratus I was to see. Lembaga llmu Pengetahuan Indonesia (Indonesian Institute of Sciences) and Perlindungan dan Pelestarian Alam (P PA) branch of the Forestry Department were my sponsors in Indonesia. I thank these institutions for providing the necessary permission to undertake research in Indonesia. I particularly wish to thank Dr Rubini Atmawidjaja, Mr Napitapulu, Mrs Moertini Atmowidjojo, Mr Ubus Wadju Maskar and the P P A staff at Pangandaran. I am very grateful to Dr J. MacKinnon and Dr H. Rijksen as my overseas supervisors. Numerous people assisted me in the field. Foremost was Mr R. John Fowler who gave so much of his time and energy during the two years in Indonesia. John Fowler was invaluable for his assistance with mapping the home-range areas of the study groups. He also assisted in the initial surveys of T. auratus groups in the Pangandaran Nature Reserve, in conducting censuses of T. auratus, in estimating tree heights, in quadrat sampling of the vegetation, in focal-animal sampling (as a "scribe") and in setting up a computer database. Others who assisted me in the field were Dr R. J aremovic; Mr R. Hill, Dr D.B. Croft, Kuswan, Ms H. Kool, Ms M. McCoy and Ms M. Crouch. My father, Mr A.F. Kool, deserves a special mention for his assistance, particularly for his forbearance and humour during the night observations. Uce assisted greatly in the vegetation sampling Acknowledgements v and, as well as being a superb tree climber, Uce's sense of humour made this task enjoyable. My sincere gratitude goes to all these people. I also wish to thank Mr and Mrs P. Hillegers, Dr F. Smiet, Ms S. Berg, and Mr and Mrs E. de Haas for logistical support in Bogor and Jakarta. Meteorological data were collected daily by the P PA staff at Pangandaran. In particular I wish to thank Mr Deden for his conscientious efforts. I am also grateful to staff at Pemeriksaan Hujan, Pangandaran and Kantor Meteorologi, Cilacap for making their meteorological records available to me. Plant identification was performed at the Bogor Herbarium with the assistance of the herbarium staff. Dr R. Geesink and Dr E.F. Vogel (from the Rijksherbarium) assisted with the classification of a few botanical specimens. Dr Kostermans assisted with the identification of Cassia species and Prof. Corner with the identification of Ficus samples. Mr Sandot (P P A, Pangandaran) shared with me his knowledge on the uses of plants at Pangandaran. Analyses of soil samples were conducted under the guidance of Dr M.D. Melville and Mr C.A. Meyers (Geography Department, The University of New South Wales). Chemical analyses of plant samples were performed under the supervision of Dr S. Cork at the Commonwealth Scientific and Industrial Research Organization laboratories, Canberra, and advice on methods was provided by Dr P.J. Waterman. I am extremely grateful to Dr S. Cork for his assistance and co-operation in allowing me to use his facilities for these analyses. Mr R. Engel (Wool and Pastoral Sciences, The University of New South Wales) analysed samples for nitrogen content. Dr A. Bagnara and Tatiana (Biochemistry Department, The University of New South Wales) assisted with labelling bovine serum albumen with Remazol brilliant blue R for the protein precipitation assay. I have benefitted greatly from verbal and/or written discussions of ideas with Drs D.B. Croft, E.L. Bennett, A.G. Davies, C.P. Groves, P.J. Acknowledgements vi Waterman, S. Cork, J. MacKinnon, K. MacKinnon, H. Rijksen, B. van Lavieren, T. Struhsaker, A.J. Whitten, R. Jaremovic, B. Wannan, G. Belovsky, B. Fox, D. Woodside, M. Elgar, Mr P. Hillegers, Prof. T.J. Dawson, Prof. I. Hume, Assoc. Prof. R. Crozier, Mr D. Maitland, Ms G. da Silva, Mr T. Clancy and Ms N. Marlow. My thanks go to all these people. Liz Bennett has been remarkable for her encouragement, support and diligence in reading drafts of a few chapters for which I am especially grateful. My thanks go to Dr D.B. Croft, Prof. D.C. Sandeman and Mr A.F. Kool for attending to administrative issues in my absence. Computing advice and assistance was provided by Dr D.B. Croft, Mr R. Griffiths and Mr G. Nippard. Mr P. Gillespie entered the focal­ animal data on to a computer database and constructed the maps presented in this thesis. Ms L. Hamence typed the reference list and Ms P. Green typed the tables. Ms L. Kool created the drawing presented as the frontispiece - an excellent image of the adult male m one of the study groups. The photographs were produced by the faculty photographic unit, The University of New South Wales. The project was funded by a Commonwealth Postgraduate Research A ward. Additional funding was provided by the Joyce W. Vickery Scientific Research Fund (Linnean Society of New South Wales) and by Mr A.F. Kool. Finally, I wish to thank Ibu and Bapak Herlan, Cucu, Lia and Pera for being a family to me and for their hospitality and kindness throughout my stay in Pangandaran. The friends and acquaintances in Pangandaran are not forgotten. My father and (late) mother, Mrs Emma W. Kool, are especially appreciated and thanked for their understanding, encouragement and support throughout my studies. vii CONTENTS PAGE Frontispiece 11 Certificate of Originality iii Acknowledgements iv Contents vii List of Figures xii List of Tables xvi ABSTRACT XX CHAPTER 1: INTRODUCTION 1.1 Colobine monkeys 1 1.2 The leaf monkeys (or langurs) of Asia 2 1.2.1 General 2 1.2.2 The colobines of Java 2 1.3 Studies of colobine ecology 5 1.4 Optimal foraging theory 7 1.5 Aims of the study 12 1.6 Summary 13 CHAPTER 2: METHODS 2.1 Introduction 15 2.2 The study area 15 2.2.1 Location, history and general topography 15 2.2.2 Selection of the study area 18 2.2.3 Climatic conditions 19 2.2.4 Edaphic conditions 23 2.2.4.1 General 23 2.2 .4 .2 Analysis of soil samples 24 2.2.5 Mammals found in the Pangandaran Nature Reserve 27 2.3 The T. auratus study groups 27 2.3.1 Selection of T. auratus study groups 27 2.3.2 Mapping of home-range areas 31 2.3.3 Habituation of T. auratus study groups 31 2.4 Monthly schedule 32 2.4.1 General 32 2.4.2 Scan sampling 35 2.4.3 Focal-animal sampling 38 2.4.4 Remainder of each sampling month 39 2.5 Statistical analysis 40 2.5 .1 Weighting of data 40 2.5.2 Statistical analysis 41 2.6 Summary 41 Contents viii CHAPTER 3: VEGETATION OF THE STUDY AREA 3.1 Introduction 44 3.2 Methods 44 3.2.1 Botanical plots 44 3.2.2 Plant part production 50 3.2.3 Phytochemistry 53 3.3 Botanical structure and composltwn 56 3.3.1 Structure of the GRP21 and GRP3 home-range areas 56 3.3.2 Botanical composition of the GRP21 and GRP3 home- range areas 65 3.3.2.1 Comparison between the GRP21 and GRP3 home­ range areas 65 3.3.2.2 Cluster analysis 70 3.3.3 Comparison with other areas in South-east Asia 72 3.4 Plant part production 75 3.5 Phytochemistry 78 3.5 .1 Phytochemistry of mature leaves in the two study sites 78 3.5.2 Comparison with other areas in Asia and Africa where colobines have been studied 81 3.6 Summary 83 CHAPTER 4: GROUP SIZE, POPULATION DENSITY, BIOMASS AND SOCIAL ORGANIZATION 4.1 Introduction 85 4.2 Methods 92 4.2.1 CA censuses 92 4.2.2 TW censuses 94 4.2.3 Social organization of T.