Ecology of Nusa Tenggara

By Kathryn Monk and Yance De Fretes

The Ecology of Nusa Tenggara and Maluku is a comprehensive ecological survey of a series ecologically diverse islands in the Pacific.

It contains extensive baseline data on the region’s people, ecosystems, biodiversity and land use, and discusses these in a historical as well as a developmental context. It also provides guidelines for scientific researchers on worthwhile ecological and socio-economic research projects.

This region is the most diverse in Indonesia. Its myriad islands range from small atolls to active volcanic islands rising 3,500 meters above sea level. Each province has extensive coastlinesonly 10 percent of the province of Maluku is land. The seas include shallow continental shelves and some of the deepest sea basins in the world. The complexity and vulnerability of these islands mean that development and environment are inextricably linked. If this is not understood and acted upon, there is no possibility for the ecologically sustainable development of Nusa Tenggara and Maluku.

• Language: English
• Publisher: Periplus Editions
• Release date: Jun 5, 2012
• ISBN: 9781462905065

Book preview

THE ECOLOGY OF NUSA TENGGARA AND MALUKU

THE ECOLOGY OF INDONESIA SERIES

VOLUME V

THE ECOLOGY OF INDONESIA SERIES

Volume V: The Ecology of Nusa Tenggara and Maluku

Other Titles in the Series

Volume I: The Ecology of Sumatra

Volume II: The Ecology of Java and Bali

Volume III: The Ecology of Kalimantan

Volume IV: The Ecology of Sulawesi

Volume VI: The Ecology of Irian Jaya

Volume VII: The Ecology of the Indonesian Seas, Part 1

Volume VIII: The Ecology of the Indonesian Seas, Part 2

Produced by

Environmental Management Development in

Indonesia Project, a cooperative project of the

Indonesian Ministry of the Environment

and

Dalhousie University, Halifax, Nova Scotia

under the sponsorship of the

Canadian International Development Agency

The Ecology

of Nusa Tenggara

and Maluku

KATHRYN A. MONK

YANCE DE FRETES

GAYATRI REKSODIHARJO-LILLEY

PERIPLUS

EDITIONS

Copyright © 1997 Dalhousie University

All maps in this edition except 601 /REPPPROT

copyright © 1997 Periplus Editions

All rights reserved

Published by Periplus Editions (HK) Ltd.

ISBN: 978-1-4629-0506-5 (ebook)

Publisher: Eric Oey

Typesetting and graphics: JWD Communications Ltd.

Distributors:

Australia:

University of New South Wales Press Ltd

Sydney NSW 2052

Indonesia:

C.V.Java Books

Jalan Kelapa Gading Kirana, Blok A14 No. 17

Jakarta 14240

Japan:

Tuttle Shokai Ltd

21-13, Seki 1-Chome, Tama-ku,

Kawasaki, Kanagawa 214

Singapore and Malaysia:

Berkeley Books Private Ltd.

61 Tai Seng Avenue #02-12,

Singapore 534167

United Kingdom:

Oxford University Press

Great Clarendon Street

Oxford, OX2 6DP

United States:

Charles E. Tuttle Co., Inc.,

RRI Box 231-5, North Clarendon,

VT 05759-9700

Printed in The Republic of Singapore

Table of Contents

EMDI xi

Foreword xiii

Acknowledgements xv

Chapter 1 Introduction 1

Historical Development of Natural History and Ecology in Nusa Tenggara and Maluku 4

SECTION I - Natural Resources

Chapter 2 Physical Overview 7

Geographical Facts 7

Geology 9

Background to Regional Geology 11

Geological Origins of Nusa Tenggara and Maluku 19

Evolution of Nusa Tenggara and Maluku 24

Emergence and Submergence of the Islands 45

Landscapes 52

Current Plate Movements and Future Geological Activity 55

Specific Information Sources 57

Environmental Hazards 59

Volcanoes 61

Earthquakes 64

Landslips and Floods 65

Climate 69

Regional Climate 69

Topographic Influences onRegional Climate 71

Seasonal Climates - Classification Systems 74

Temperature 79

Specific Information Sources 81

Microclimate 83

Hydrology 84

Surface Water 85

Important Management Points 92

Ground Water 95

Important Management Points 98

Specific Information Sources 99

Soils 101

Geology and Soil Development 101

Topography and Soil Development 107

Climate and Soil Development 107

Altitude and Soil Development 111

Soil Classification 111

Important Management Points 134

Specific Information Sources 135

Chapter 3 Marine and Coastal Ecosystems 137

Open-Sea Ecosystems 139

Currents 139

Waves 140

Productivity 141

Coastal Ecosystems 142

Coral Reefs 142

Seaweed and Seagrass Beds 149

Seashores and Beaches 153

Mangroves 158

Swamp Forest 164

Estuaries 164

Rivers and Lakes 166

Physical Patterns and Characterstics of Lakes and Rivers 167

Aquatic Plants 169

Phytoplankton 173

Invertebrates 175

Fish 177

Waterbirds 180

Amphibians and Reptiles 183

Conclusion 184

Chapter Summary 185

Chapter 4 Land Habitats 187

Classification of Vegetation Types 188

Classification of Secondary Vegetation 195

Vegetation Distribution in Nusa Tenggara and Maluku 197

Present Forest-Cover Statistics 202

Historical Forest-Cover Statistics 210

Ecological Information Sources 211

Heath Forest 214

Structure 215

Distribution 215

Secondary Vegetation 216

Lowland Rain Forest 216

Structure 217

Distribution 234

Secondary Vegetation 237

Forest on Ultrabasic Rocks 241

Structure 244

Distribution 245

Forest on Limestone Rocks 245

Structure 245

Distribution 248

Tropical Montane Forest 249

Structure 254

Distribution 262

At the Tree-Line 268

Lowland Monsoon Forest 269

Structure 270

Distribution 276

Secondary Vegetation 283

Savanna and Grassland 290

Structure 290

Distribution 297

Summary 299

Chapter 5 Biodiversity and Biogeography 301

Geographical Variation in Biodiversity 301

Basic Concepts 303

Biogeographical Relationships 309

Fossil and Introduced Flora and Fauna 314

Biodiversity in Nusa Tenggara and Maluku 321

Indicator Species 323

Flowering Plants 324

Ferns 327

Lichens and Bryophytes 327

Molluscs 328

Insects 331

Cave Fauna 339

Freshwater Fish 341

Amphibians and Reptiles 342

Birds 344

Mammals 367

Annexe 5.1. Checklist of Endemic Plants 381

Annexe 5.2. Checklist of Land Molluscs 393

Annexe 5.3. Checklist of Dragonflies and Damselflies 405

Annexe 5.4. Checklist of Catantopine and Acridid Grasshoppers 411

Annexe 5.5. Checklist of Swallowtail Butterflies 415

Annexe 5.6. Checklist of Carabid Beetles 417

Annexe 5.7. Checklist of Freshwater Fish 423

Annexe 5.8. Checklist of Amphibians 431

Annexe 5.9. Checklist of Reptiles 433

Annexe 5.10. Checklist of Birds 439

Annexe 5.11. Checklist of Mammals 457

SECTION II - Human Resources

Chapter 6 People and Society 465

The Origins of the People of Nusa Tenggara and Maluku 467

Modern People of the Region 474

Societies 478

General Characteristics of the Societies 478

Land Settlement and Population Distribution 487

Settlements 487

Factors Affecting Settlements and Populations 488

The Increase in Populations Since the Mid-Nineteenth Century 503

Future Trends 515

Chapter 7 Traditional and Modern Environmental Laws 519

Traditional Views or Perceptions on the Natural World 520

Folk Classification Systems 521

Traditional Natural Resource Utilisation Ethics 525

Adat in Nusa Tenggara and Maluku 527

The Sasi System of Maluku 537

Traditional Land Tenure 557

Future Application 560

From Adat to Modern Ethics and Environmental Laws 561

SECTION III - Resource Use 575

Chapter 8 Marine Resource Use

Trochus Fishery575

Sea Cucumber (Holothuridae)(BêchedeMer) 577

Traditional Whale Hunting 578

Shark Fishing 581

Nyale Harvesting Season 583

Turtle Hunting 583

Shrimp Fisheries 587

Commercial Fish Industries 589

Pearl Oysters 591

Coral Mining 592

Marine Tourism 593

Marine Conservation in Indonesia 595

Conclusion 598

Chapter 9 Land Resource Use: Forests 601

Forestry Land Classification 601

Pressures on Forestland and the Need for Management 606

Logging 607

Concession Licenses 609

Mapping Concessions 613

Concession Management Systems 614

Conservation of Biodiversity withinLogging Concessions 621

Industrial Activities 626

Commercial Forest Plantations 630

Reforestation and Regreening 635

Reforestation Programme Success 637

Reforestation for Timber Supplies 637

Reforestation for Soil and WaterConservation 638

Reforestation for Social Forestry 641

Reforestation for Conservation of Biodiversity 641

Non-timber Forest Products 642

Beeswax and Honey 644

Bamboo and Aiang-Alang 646

Rattan 647

Incense 649

Sandalwood 650

Cajuput 653

Cinnamon 654

Fuelwood 654

Traditional Indigenous Knowledge 658

Mining and Oil Extraction 668

Mining and Oil Resources of Nusa Tenggara and Maluku 670

Summary 679

Chapter 10 Land Resource Use: Agriculture 681

Agro-ecosystems 682

Forest Dwellers 684

Sago 687

Savanna-Based Palm Agro-ecosystems 690

Shifting Cultivation 692

Swidden 693

Shifting Cultivation Crops 699

Pioneer Shifting Cultivation and Permanent Dryland Farming 710

Permanent Cultivation 718

Agroforestry 718

Commercial Cultivation 738

Pest Management 752

Integrated Pest Management 755

Animal Husbandry 757

Extensive Management System 758

Intensive Management System 759

Corral and Home Gardens 760

Cattle 760

Water Buffaloes 769

Horses 771

Small Livestock 772

Agricultural Development inMarginal Environments 774

Summary 775

Chapter 11 Conservation 777

Biogeographical Units and Significance to Conservation 780

Nusa Tenggara 780

Maluku 782

Protected Area Types and Management 786

Protected Species of Nusa Tenggara and Maluku 789

Reserve Management in Nusa Tenggara and Maluku 804

Reserve Size and Shape 812

Reserve Location 815

Marine Reserves 816

Problems with Conservation 821

Animal Trade in Nusa Tenggara andMaluku 824

New Approaches in Conservation 841

Research Needs and Linkages to Support Conservation Works 842

Summary 844

Annexe 11.1. List of Protected Species in Nusa Tenggara and Maluku 845

Annexe 11.2. Details of the Protected Areas of Nusa Tenggara and Maluku 851

Annexe 11.3. Threats to the Protected Areas of Nusa Tenggara and Maluku 861

Chapter 12 Summary 865

Appendix 1. Information on Each Island or Island Group in Nusa Tenggara and Maluku 871

Appendix 2. List of Expeditions and Collections in Nusa Tenggara and Maluku 881

Appendix 3. Comparisons of Soil Classification Systems 887

Appendix 4. Abbreviations Used in Text for Higher-Plant Family Names 889

Appendix 5. References Giving Local Language Names for Plants and Animals in Nusa Tenggara and Maluku 891

Appendix 6. Useful Addresses of Local Universities, Field Stations and Government Institutes 895

Bibliography 897

Index 951

EMDI

The Environmental Management Development Project (EMDI) was designed to upgrade environmental management capabilities through institutional strengthening and human resource development. A joint project of the Ministry of State for Environment (LH), Jakarta, and the School for Resource and Environmental Studies, Dalhousie University, Halifax, Nova Scotia, EMDI supported LH's mandate to provide guidance and leadership to Indonesian agencies and organizations responsible for implementing environmental management and sustainable development. Linkages between Indonesian and Canadian organizations and individuals in the area of environmental management are also fostered.

EMDI received generous funding from the Canadian International Development Agency (CIDA). CIDA provided Cdn$2.5 million to EMDI-1 (1983-86), Cdn$7.7 million to EMDI-2 (1986-89), and contributed Cdn$37.3 million to EMDI-3 (1989-95). Significant contributions, direct and in kind, were made by LH and Dalhousie University.

EMDI-3 emphasised spatial planning and regional environmental management, environmental impact assessment, environmental standards, hazardous and toxic substance management, marine and coastal environmental management, environmental information systems, and environmental law. The opportunity for further studies was offered through fellowships and internships for qualified individuals. The books in the Ecology of Indonesia series form a major part of the publications programme. Linkages with NGOs and the private sector were encouraged.

EMDI supported the University Consortium on the Environment comprising Gadjah Mada University, University of Indonesia, Bandung Institute of Technology, the University of Waterloo, and York University. Included in EMDI activities at Dalhousie University were research fellowships and exchanges for senior professionals in Indonesia and Canada, and assistance for Dalhousie graduate students undertaking thesis research in Indonesia.

For further information about the EMDI project, please contact:

Director

School for Resource and Environmental Studies

Dalhousie University

1312 Robie Street

Halifax, Nova Scotia

Canada B3H 3E2

Tel. [phone]

Fax. [phone]

Foreword

For too long, both Indonesians and other nationalities working in, or thinking of working in, Nusa Tenggara and Maluku have believed that little was known about the natural resources of the region. As this book amply demonstrates, a massive amount of material was available but was scattered and difficult to access. Development and research programmes alike faced the daunting task of establishing the known facts before beginning their own work. Too frequently, work was repeated, or worse, abandoned because no reference material was available.

For over four years the authors and their support teams have worked throughout the region, indeed throughout Indonesia and many other countries, to comply and analyse the varied and detailed information presented here. They have been helped tremendously by many others, particularly residents of the region itself.

Nusa Tenggara and Maluku is the least known of the regions covered by the Ecology of Indonesia series, but the most vulnerable and complicated. This collection of small, mainly oceanic islands rises from some of the deepest and richest seas on Earth and acts as a corridor between two major biogeographical regions of the world. The book constantly underlines the fact that much baseline data is known and that the way forward is to now examine the interactions between the people and the varied flora and fauna within this environmentally sensitive marginal region. The title The Ecology of Nusa Tenggara and Maluku is thus perhaps misleading. The ecological studies are waiting to be done. I hope that this book will encourage our students, scientists, and administrators to look afresh at this region.

The sustainable development of small islands is sufficiently different from that of larger land masses to have warranted a United Nations Global Conference of its own in Barbados in 1994. It is my hope that this book will draw attention to the importance of the ecology of Nusa Tenggara and Maluku in the wake of this conference and in the light of the Government of Indonesia East Indonesia Development Programme.

Sarwono Kusumaatmadja

State Minister for Environment

Jakarta, February 1996

Jakarta 10110, Indonesia

Tel. [phone]

Fax. [phone]

Acknowledgements

The following people have been particularly active in the production of this book, as research and field assistants, typists, copy editors, general organisers, and supporters: A. Bharata, E. Farndon, M. Hasibuan, I. Hasibuan, R. Jarvis, S. Johannesen, A. Kartikasari, B. Libby, A. Mann, Marzan, K. Morley, R. Murphy, R. Ounstead, D. Oura, G. Pegasiou, D. Purbawati, A.Rahma-tiningsih, I. Ros, L. Safarian, A. Steenhout-Kurnianingsih, M. Supanra, A. Tucker, S. Wales, J. Whitten, and P. Witten, as well as EMDI personnel in Jakarta and at Dalhousie University.

We would like to thank Mr. Rokhmin Dahuri who compiled most of the information and references for chapters 3 and 8.

A vast number of people and organisations have provided material or read manuscripts. With apologies for any omissions, we extend grateful thanks to: Pak Abdullah, K. van Achterberg, F. Adema, W. Adisoewignyo, O. Alfonse, D. Alwi, M. Amir, L.S. Anema, N. Angerilla, M. Argeloo, I.B.K. Arinasa, D. Antell, H. Ataupah, M. Atmowidjojo, M. Aziz, P. Baas, Pak Baharudin, A.B. van Balen, M.M.J. van Balgooy, L. Banilodi, A.J. Barber, C. Barraud, K. Barta, F. von Benda-Beckman, R. Betts, C. Billington, H.Blaauw, L. Blair, Pak Boeadi, C.J. Bohm, P. Bolding, A. Brouwer, A. Budiman, L. Bury, J. Caldecott, T.J. Casadevall, S. Chaerudin, M. Cock, N.M. Collins, M. Cooke, R. Dahuri, Pak Dami, L. Deharveng, W. van Diest, R. Dilts, Djwa H.L.J. Dransfield, S. Dransfield, P. Ede, R. Effendi, G. El Ba, L.S. Eldredge, R. Ellen, C. Fandeli, L. Fisher, T. Flannery, C.Fransen, T. Ford, Fuji Films (Jakarta), M. Fujita, W. Giesen, I. Glover, N. Guppy, G.J. Knaap, D. Greathead, R. de Groot, M. Hadley, L. Haines, S. Halik, R. Harman, Pak Haryadi, A. Hay, K.J. Heij, P. Hewitt, P. Hillyard, A. Hiroyuki, J. Holloway, D. Holmes, G. Hope, P. Horning, K. Horde, B. von Hos, R. How, M. Indrawan, H. de Iongh, D.T. Iskander, R. Izaac, J. James, J. Jarvie, P. Jepson, R.J. Johns, R. de Jong, K. Kartawinata, E. Karya, M. Kato, S-I. Kato, E.R. Katiman, B. Kay, D. Kitchener, M. Kottelat, J. Krikken, R.H. de Kruyff, F. Lackner, J. van der Land, A.M. Latucosina, R.E. Latucosina, S. Latucosina, G.J. Laving, C. Lees, K. Leggett, J. Leith, A. Leeman, F.P. Lesnussa, B. Levett, R. Lilley, R. Lindsay, T. Loran, G.C. Loresto, G.L. Lucas, C. Lut, D. MacCall, A. Macdonald, K. MacKinnon, M. Ma'shun, G.F. Mees, W. Meijer, D. Mochtar, S. Moss, Muhari, K. Muller, J. Munneke, S. Murphy, M. Nanere, S. Nash, H. Nooteboom, M.K.J. Norimarna, Nur-jamil, B. Ohoiwutun, G. dinger, O.S.R. Ongkosongo, M. Ounstead, M. Palmer, M. Pandjaitan, J. Patterson, L. Pierce, C. Potter, Pak Putinella, M. Qazuni, T. Raharjo, E.S. Reese, M.I. Renwarin, Pak Riswan, C. Roberts, G. Roberts, G. Robinson, G. Rochlin, M. Roos, Rudyanto, D. Saatulete, J.C. Sairlele, H. Salempessy, L.Sangadt, B. Sarbini, H. Scheider, Sempati Airline, M. Silvius, Siswoyo, D. Shaw, T.S. Silitonga, F. Smeit, C. Smeenk, L. Smith,

H. Soedjito, D. Soenarijati, N. Soetjipto, A.P.C. Sol, I. Staff, P. Sujana, K. Sumdahiharga, Y. Sumakud, J. Supriatna, J. Suryadi, E. Sutter, E.J. Swartzentruber, J. Taylor, R. Teeuw, P.A. Titlaey-Pupella, J. van Tol, A. Touw, R. Trussell, G. Tucker, M. Usman, J.F. Veldkamp, J. Vermeulen, J.A.J. Verheijen, S. Vink, E. de Vogel, C. Wallace, E. Widjaya, E.H. Wahyono, P.C. van Welzen, A.T. Wignijoprajitno, J. Weir, A. Welsh, B. Wenno, L. Wenno, G. White, T. Whitmore, A.J. Whitten, M. Wickenden, K.F. Wiersum, F.M.H. Willemse, S. Wodicka, J. Wood, F. Wuritmur, P.S. Wyse Jackson, B. Yates, F.B. Yuwono, R. Zweifel.

Particular thanks must go to the following institutions and companies: in Indonesia - Herbarium Bogoriense and Museum Zoologicum Bogoriense, PT Newmont Nusa Tenggara, Mataram and Jakarta, Barito Pacific Timber Jakarta, Ambon, Ternate, Halmahera, and Morotai, Djajanti Group, Ambon and Seram; in The Netherlands - the Rijksherbarium and Natuurisches Museum, Leiden; in England - the Natural History Museum London, the Royal Botanic Gardens Kew, and the World Conservation Monitoring Centre. G.R. Lilley would like to thank the World Wildlife Fund Indonesia Programme for their encouragement and support in writing the chapter on marine and coastal ecosystems.

COPYRIGHT

Every effort has been made to contact copyright holders; in the event of an inadvertent omission or error, the senior author should be notified via the publishers. Full acknowledgements are given in the text. Two major publications have, however, been cited extensively and the copyright holders have been most generous in allowing the use of their materials. Due acknowledgement is therefore given here for permission to reproduce material from the Regional Physical Planning Programme for Transmigration (RePPProT) by permission of the Indonesian Ministry of Transmigration and the U.K. Overseas Development Administration as co-sponsors of RePPProT, and from the Flora Malesiana series and in-house publications by permission of the Rijksherbarium, Leiden, The Netherlands. The Rijksherbarium also allowed KAM full and free access to the unfinished and unpublished manuscript of Flora Malesiana Volume 2, Malaysian Plant Life, by Professor C.G.G.J. van Steenis. This amazing piece of work by one of the pioneers of tropical botany would have described each vegetation type within Malesia and provided an invaluable entry into the colonial literature. Because of the importance of van Steenis's work, the usual rule of not citing unpublished material has been ignored, and it appears as (van Steenis unpublished). KAM is extremely grateful to Professor Pieter Baas, as director of the Rijksherbarium, for this access.

All photographers have allowed their photographs to be used free of charge, except for those colonial photographs provided by the Royal Tropical Museum, Amsterdam, which made a considerable reduction in their fees to support this programme. This book has been published without any royalty payments to the authors or photographers.

Chapter One

Introduction

God will not ask thee thy race

Nor thy birth

Alone he will ask of thee

What hast thou done with the land I gave thee. — PERSIAN PROVERB

INTRODUCTION

This book deals specifically with the four Indonesian provinces of West Nusa Tenggara (WNT), East Nusa Tenggara (ENT), East Timor, and Maluku, referred to collectively here as Nusa Tenggara and Maluku (NT&M). These provinces are composed of the smallest islands in Indonesia, of archipelagoes within archipelagoes. As such, they have been frequently excluded from general discussions in which reference is made to the six major areas of Indonesia: Sumatra, Java, Bali, Kalimantan, Sulawesi, and Irian Jaya.

While many ecological and environmental problems are common to both small islands and larger landmasses, small islands have their own particular problems. In particular, pressures for development on small islands are increasing while the effects of such development are not always anticipated. In a country generally rich in natural resources, the small islands of NT&M have much more limited and specialised natural resources upon which to draw for survival. Not only that, but these islands often have limited human resources. General observations made by Beller et al. (1990) and Hess (1990) on islands of approximately 10,000 km² or less and with less than 500,000 people can be applied to much of NT&M. On such islands:

• a higher proportion of their landmass will be affected by volcanic eruptions, earthquakes, landslips, and cyclone damage;

• climates are more directly maritime;

• water catchment areas are smaller and erosion levels higher;

• coastal regions make up a higher percentage of land;

• their environments may be more specialised, with a higher proportion of endemic species in an overall depauperate community;

• societies may have developed in more isolation and retain a strong sense of culture;

• economically driven immigration and emigration have a larger effect on small island populations.

Box 1.1. Island nomenclature.

A note is needed on the title of this book: The Ecology of Nusa Tenggara and Maluku. More historically minded readers might wish to use the terms Lesser Sunda Islands and the Moluccas. The Lesser Sunda Islands, however, referred to Bali, WNT, and ENT. East Timor was under Portuguese rule until 1975 and usually excluded from this area. The origin of the name Maluku is still under dispute. The old Arab traders' name for the region was Jazirat al-Muluk (the land of many kings). The word Moloko, however, is Galelarese or Tobelorese (languages of Halmahera) for mountain and may have been the old name for Ternate. Whatever the source, the name was corrupted into Maluku and later used collectively for the main spice-producing islands of Ternate, Tidore, Makian, Moti, and Kayoa (Watuseke 1977). Europeans further corrupted the name to the Moluccas and widened the geographical area to include the islands of Ambon, Seram, Buru, Sula, Obi, and Halmahera and its adjacent islands. The remaining islands encircling the Banda Sea in the south, the Kai, Tanimbar, and Aru Islands, and the volcanic islands from Banda south to Wetar, were in geographical limbo. Maluku is now the name for the penultimate eastern province in Indonesia.

The spellings of names for islands, towns, mountains, and rivers within NT&M have varied over the years. We use the spellings used most often by the Indonesian government (but see also appendix 1). For further reading, note that mountain is gunung in Indonesian, river is sungai, archipelago is kepulauan, island is pulau, and islet is gili.

Both environmentally and economically then, small islands are very exposed to external forces. As Brookfield (1990) says, vulnerability is almost directly correlated to small size.

The book begins with a detailed physical overview of NT&M, its geological origins and its propensity for environmental hazards, its hydrology, climate, and soils in chapter 2. It continues with chapters on marine, coastal, and terrestrial habitats (chapters 3 and 4). Existing information on the species diversity is presented in chapter 5 with reference to biogeography and selection of biological indicators for both conservation and environmental impact assessments. Much of this book, however, is devoted to discussions of current resource use and management.

Social problems arise when development occurs in isolated areas using imported labour. Frontier villages grow up nearby to supply basic needs but wages go out of the province, local people become alienated, and not involved in the process. Information on the people, their societies, and their approach to land management through traditional and modern laws are discussed in chapters 6 and 7.

To allow these islands to develop in an ecologically sustainable way, avoiding huge outside support, their vulnerability must be recognised, the environmental services of the restricted natural resources of these small islands realised, and the long-term impacts of natural resource use understood (Beller et al. 1990). Forested land, for example, maintains adjacent ecosystems and water catchment areas, and prevents distant but far-reaching impacts such as the destruction of reefs and marine life. Major efforts to conserve the limited water supplies of these islands are needed, and forests can be used to prevent water quality degradation and flooding, as well as minimising water shortages. Chapters 8 (marine and coastal), 9 (forests), and 10 (agriculture) deal with the marine and land resource use in NT&M.

Reference is made to industrial development but as yet this is mainly restricted to small-scale industries dependent on limited human and natural resources, manufactured or semi-processed products from agriculture such as dried hides and skins, peeled and dried tamarind, cashews, processing of other fruits, and dried sea products that are mostly supplied to the markets in Java. Development of large- and medium-scale industries is small as the limited resource base means expensive transport costs compared with Java, nearer to main markets. Examples include a shrimp processing factory in the Aru Islands, a plywood and glue factory in the Sula Islands, and plywood factories on Seram. Tourism is a major development for the future and aspects of this are discussed in specific sections throughout the book.

Conservation of specific areas is attracting a number of programmes in NT&M and these are presented in chapter 11.

The government of Indonesia had identified NT&M as a priority region for development in REPELITA V (the 1989-94 five-year plan). The need for an appreciation of the limitations and the unique aspects of NT&M is acute. So too is the need for good environmental management. Important areas for environmental management include:

• gathering, accessing and disseminating environmental information;

• investigating techniques for natural resource and environmental inventory, including remote sensing and monitoring of remote areas;

• promoting an environmental ethic within government, industry and society;

• studying traditional resource use management and incorporating ecological, economic, and social considerations into resource management theories;

• upgrading natural resource management, including parks, other forest and natural resource areas, river basins, and coastal zones;

• providing general environmental education and specialist training;

• finding workable environmental strategies, including cost-effective monitoring mechanisms, regulations of toxic waste disposal, control of marine and coastal pollution, and protection of fragile environments and the habitats of migratory species (Hainsworth 1984).

This book should facilitate at least some of these aims within NT&M.

HISTORICAL DEVELOPMENT OF NATURAL HISTORY AND ECOLOGY IN NUSA TENGGARA AND MALUKU

The most famous book readily available as an introduction to NT&M is Alfred Wallace's (1989 [1869]) inimitable The Malay Archipelago. In fact, the natural history of NT&M has been a source of fascination for collectors for centuries and Maluku is the source of two major historical works of natural history in the world. George Everhard Rumpf (Rumphius) (1627-1702) settled in 1657 in Ambon while employed by the Dutch East Indies Company (Vereenigde Oost-Indische Compagnie: VOC). He became an expert natural historian and, despite tremendous setbacks (he became blind, his wife and a daughter were killed when an earthquake demolished his house, a fire destroyed his collections and drawings, and manuscripts were lost at sea), he wrote the Herbarium Amboinense and the Amboinische Raritaten-kamer. Even so, by the time he died in 1702, his work was unpublished; in fact the vast Herbarium Amboinense, to which he devoted 40 years, did not appear until 1741-50 (Stearn 1957). The work covers 1200 species, 930 can be given definite species names, and another 140 can be identified to genus level (Merrill 1914). Rumphius provided illustrations and descriptions for nomenclature types for 350 plants. His material contributed to the later development of the binomial scientific classification by Linneaus. As will be noted through this book, his work is still referred to today.

Following in his footsteps were many other employees of the VOC and of rival companies and governments who came out to the Archipelago in pursuit of trade. Nearly every exploratory fleet had at least one officer, often the medical doctor, who would record the natural history of the islands visited or passed, if not take specimens. It was not until the resumption of Dutch rule of the Indonesian islands after the British occupation, however, that more rigorous study was undertaken. The Physical Commission (Natuurkundige Commissie) was instigated to study all natural resources of the region, including the flora and fauna that might lead to further economic development (Roepke 1957). Expeditions were then undertaken specifically to collect specimens. People from The Netherlands and elsewhere came out to the Archipelago, travelling to remote areas with the support of the Dutch East Indian government and its officials or as independent collectors. Major botanical and zoological collections from NT&M are now housed in Europe's largest museums, especially in The Netherlands, Germany, Switzerland, and Italy. The Dutch published much geological and geographical information during the colonial period, particularly detailed being the Yearbooks of the Mining Corporation of the East Indies Archipelago (Jaarboek van het Mijnwezen in Nederlandsch Oost-Indie) (for example: Brouwer 1921 for Halmahera, Bacan, Tanimbar, and Kai Besar; Verbeek 1905 for Ambon). Other sources of information on the historical collections are listed in appendix 2.

Following the establishment of the Republic of Indonesia, anthropological studies flourished, with many individuals working in the region in the late 1960s and 1970s. Since the 1980s, however, interest in NT&M has grown and many scientific expeditions have added to the knowledge of the region's natural history. Ecology, however, is still a nascent field in NT&M. The state universities have departments of agriculture, animal husbandry, forestry, and fisheries, but none have a biology department or an ecology research group. The Environmental Study Centres are growing and their staff have attended Environmental Impact Assessment (EIA) courses, but, as yet, there are few ecological research programmes in the region. Most of the foreign expeditions into the region, as much by necessity of time restrictions as by interest, are taxonomically orientated, but two outstanding ecological research programmes have been carried out in NT&M and can serve as models for future work.

In NT, a study of the behavioural ecology of the Komodo dragon Varanus komodenesis (Varadidae) illustrates the ecological study of a single animal (Auffenberg 1981). Relevant data on the microclimate, vegetation, population dynamics, and prey species all contributed to an understanding of how the Komodo dragon interacts with its environment.

In Maluku, extensive research was carried out in mangrove ecosystems of Halmahera, Seram, Ambon, and Kai, with studies on mangrove forest structure, function, and population dynamics, the taxonomy and ecology of mangrove-associated algae, and animal ecology studies on associated crustaceans and molluscs. This illustrates the whole gamut of ecological studies based on one ecosystem, from taxonomically based plant species distribution surveys to their reproductive ecology and the feeding ecology of associated animals.

The expeditions during the late 1980s and early 1900s to Seram have led to the publication of the first island-based monograph in NT&M (Edwards et al. 1993a), and the many expeditions of the Western Australian Museum with the Museum Zoologicum Bogoriense since 1987 should allow a major reassessment of the vertebrate fauna of NT within the near future.

This book is thus a compilation of information from colonial and recent research plus some original surveys carried out within NT&M, and should provide baseline data on the ecology of the area, its ecosystems, biodiversity and land use. The preliminary checklists and descriptions of habitats presented here should, it is hoped, encourage the production of basic field guides as well as more ecological studies. We hope that readers will find the book valuable as a basic reference for the natural history and ecology of the area, as a stimulus for further research, and as a guide to handling such data from the perspective of environmental management. We hope that it underlines the need for solid scientific research that can be applied to the realities of practical conservation problems and useful, predictive environmental impact assessments. Despite the obvious gaps in our information, readers should bear in mind that it is certainly better to have a rough answer to the right question than the precise answer to the wrong question.

Chapter Two

Physical Overview

Nusa Tenggara and Maluku (NT&M) is unlike any other region in Indonesia. It encompasses innumerable volcanic and coral reef islands scattered through some of the deepest seas in the world, and has no large islands such as Java or Sumatra. The area of Java, 132,000 km², is six and one-half times that of the largest island in NT&M, Halmahera, at 20,000 km². This region occurs at the heart of the complex crossroads of two continents, Asia and Australia, and two oceans, the Indian and Pacific. While this strategic position is a result of geological history, the climate, hydrology, and soils must also be considered if the biological, social, and economic life of the region is to be understood. An excellent review of the physical features of NT&M is supplied by the Regional Physical Planning Programme for Transmigration (RePPProT) in both Indonesian and English, but this is not widely available (RePPProT 1989a,b). However, every Regional Development Planning Board (Badan Perencanaan Pembanguan Daerah: BAPPEDA) in each provincial capital should hold a complete set of the relevant RePPProT reviews and maps.

GEOGRAPHICAL FACTS

The four provinces within NT&M cover approximately 159,000 km², some 8% of Indonesia (1,920,000 km²) (table 2.1). They stretch 2850 km from west to east (115°49' E to 134°54' E) and 1450 km north to south (2°36' N to 11° S). The small island of Pamana off Rod in East Nusa Tenggara (ENT) is the most southerly island in Indonesia, lying exactly on latitude 11° S, and therefore is the Indonesian island closest to Australia. Kupang, the provincial capital of ENT, is only about 800 km from Darwin, north Australia.

It is worth noting that figures for land and sea areas within NT&M vary considerably between sources, even between government departments; it is an extremely difficult region to map because of the innumerable islands. In this book, figures available from RePPProT (1989a), which are derived from satellite data, are given priority. This means that statistics

from other sources may not correspond. Estimates of the total number of islands in NT&M also varies considerably, but islands over 100 km² in area are listed in table 2.1. More accurate data on both the number and the size of these islands should be available soon as a large number of land and sea resource projects are presently in operation. Most of the islands within each island group are listed in appendix 1, with areas, where known, along with their provincial government position. Some island groups have many island members; the Tanimbar Islands, for example, comprise some fifty islands (Damen 1983).

1 Percentage of Indonesia's land cover.

2 Provincial areas calculated by RePPProT 1989a based on Ministry of Forestry figures.

3 Provincial areas proposed by RePPProT 1989a.

4 Provincial areas used by Ministry of Forestry.

Sources: BPS 1991; Carson and Abdullah 1976; LTA-72 1988a; RePPProT 1989a.

None of the islands of NT&M has an area of more than 20,000 km², except perhaps Halmahera. Approximately 84% of the islands are less than 10,000 km² in area. This high frequency of small islands means that NT&M is dominated as much by sea as by land. Maluku, often described in tourist literature as having 999 islands, is 90% sea: its land area is 77,990 km², while another 776,500 km² is sea, emphasising the utmost importance of marine resources to this province.

GEOLOGY

Geology is physically and metaphorically the basis of our understanding of ecology. The origins of these islands and the processes through which they were created, and are still being produced, influence their present-day position, size, and shape. Interacting with the climate to produce soils, geology influences the distribution and abundance of plants and animals. Not only that, but NT&M comprises one of the most geologically complex and active regions in the world. Overviews of the geology, lithology, and geomorphology of the area are given by van Bemmelen (1949), Hamilton (1979), Hutchison (1992), and RePPProT (1989a). The distribution and abundance of animals and plants are affected by a range of tectonic phenomena, from explosive volcanic eruptions to frequent earthquakes and ensuing tsunamis (the latter commonly but incorrectly referred to as tidal waves, having nothing to do with tides). In particular, most of the islands are very young geologically, being from 1 to 15 million years old (Audley-Charles 1987; Hall and Nichols 1990) and the oceanic islands have never been attached to larger landmasses. Their age and isolation are very significant for the evolution of their flora and fauna. Immigration is restricted and species that do colonise these islands are then isolated, tending to evolve into an endemic biota.

Despite there being a long history of geological study within NT&M from early colonial times (for example, Brouwer and Molengraaff 1915; Germeraad 1946; Verbeek 1900, 1905) to the present day, its formation and continued geological progression are not yet fully understood (an international conference on the tectonic evolution of Southeast Asia was held in London in December 1994). Theories of these islands' geological evolution have changed extensively during the last twenty years, with more detailed understanding of the earth's crustal movements.

The complexity of NT&M originates from its position at the meeting point of four geological plates and two continental blocks. The Indonesian Archipelago encompasses three shallow, submarine, continental shelves, the Sunda Shelf off mainland Southeast Asia and the Sahul and Arafura Shelves, which form the continental shelf off northwest Australia and between Australia and New Guinea, respectively (fig. 2.1). These shelves result from millennia of erosion of the continental mass and the build up and consolidation of debris along the margins as sea levels rose and fell.

The islands of Sumatra, Kalimantan (part of Borneo), Java, and Bali lie on the Sunda Shelf and are therefore part of the Asian block. Irian Jaya (the western part of New Guinea) lies on the Arafura Shelf and is part of the Australian block. The area between these two shallow seas is known as Wallacea, encompassing Sulawesi and the myriad smaller islands of NT&M. Within this region of small islands lie some of the deepest seas in the world, plunging to depths of 7000 m.

This mosaic of deep sea basins, island chains, and shallow continental shelves is the most geologically complex and tectonically active region within Indonesia (Audley-Charles 1981). To understand the present positions of the islands of NT&M and why they experience so many earthquakes and volcanic eruptions, some background discussion of the structure of the earth and its surface movements as determined by plate tectonics is needed.

Box 2.1. Wallacea, Alfred Wallace, and the Wallace Line.

Wallacea is named after the nineteenth-century British naturalist Alfred Russel Wallace (1823-1913), who spent some eight years travelling 22,500 km and collecting 125,000 specimens of animals within the Indonesian Archipelago (Wallace 1989 [1869]). His book The Malay Archipelago is still one of the most important on the natural history of Indonesia, especially for many of the smaller islands in what we now call Wallacea.

Wallace also gave his name to the Wallace Line, running between Borneo and Sulawesi and Bali and Lombok, which he thought divided the Asian fauna from the Australian fauna. The Wallace Line actually runs along the edge of the Sunda Shelf, marking the edge of the Asian or Oriental region. Another faunal dividing line, Weber's Line, was later drawn to mark the main western limit of Australian fauna, and follows the edge of the Sahul Shelf. Wallacea lies in between. Biogeography will be discussed in detail in chapter 5, but it is as well to remember from the beginning that geology underpins this subject as well.

Background to Regional Geology

The earth's interior comprises three main parts: core, mantle, and crust. The innermost core is solid, while the outer core is liquid. The hot, dense, viscous middle part, called the mantle, is divided into the lower mantle or asthenosphere, which is capable of ductile flow because it is near its melting point, and the upper mantle. The brittle upper mantle and the thin, hard crust that sits on top of the mantle are collectively called the lithosphere. The lithosphere is commonly about 100 km thick.

The crust is differentiated into two types, continental and oceanic (fig. 2.2). Continental crust is produced by the differentiation and crystallisation of relatively light, silica-rich material. Most of the continental crust was formed during the Precambrian, which ended some 570 million years ago, but continental crust is still being produced today in accretionary complexes and volcanic arcs above subduction zones. It is thinner under continental margins (35 km) than under mountains (60 km). Oceanic crust is thinner (5-15 km) but denser than continental crust (3.0 g/cm³ compared with 2.7 g/cm³).

Oceanic crust is produced when continents break up or fracture due to changes in convection currents within the earth's mantle, in such a way that mantle material wells up and solidifies at spreading centres or rifts. Today, most such rifts are mid-oceanic.

Plate tectonic theory proposes that the earth's crust is split into separate pieces or plates like a jigsaw puzzle. One plate can comprise both oceanic and continental crust; the Pacific Plate only comprises oceanic crust, for example, whereas the Indo-Australian Plate is made up of both oceanic and continental crust. Unlike a jigsaw puzzle, however, each plate can change shape over time with the addition of new material and the loss of older crust. Figure 2.3 shows the current plates and plate boundaries of the world.

Eastern Indonesia is at the junction of four main plates: the Indo-Australian Plate, the Pacific Plate, the Eurasian Plate, and the Philippine Sea Plate. It is the interactions along these plate boundaries that produce the complex geology and the tectonic activity of NT&M.

Three types of plate boundaries exist: transcurrent, extensional and collisional (fig. 2.4).

When new oceanic crust is produced in the rift at an extensional plate boundary, it moves down the slope of the ridge, cools, becomes more dense, and subsides to form the ocean floor. This new crust formed at the ridge increases the total area of crust, and so somewhere else there must be a collisional boundary. Here, crust is either compressed, wrinkling upwards to form mountains, or resorbed (subducted) into the earth's mantle by gravitational sinking at subduction zones (fig. 2.5). Only oceanic crust, because of its heavier density, is completely subducted. When continental crust reaches the subduction zone, subduction slows down or stops. Subduction zones produce characteristic volcanic island chains or arcs along their lengths. The material forming the volcanoes (magma) comes mainly from the wedge of mantle overlying the down-going or subducting plate. The mantle partially melts to form magma when its melting temperature has been lowered by volatiles (water and carbon dioxide) that are driven out of the descending and increasingly hot oceanic crust. Associated with these volcanic arcs are sea basins as shown in figure 2.1.

Figure 2.1. Major geological features of the Indonesian Archipelago.

After RePPProT 1990b.

Figure 2.2. The internal structure of the earth.

NT&M follows two arcs, the western Sunda Arc and the eastern Banda Arc. The trench associated with the Sunda Arc is the 6-km-deep Sunda Trench, which stops at about 122° E, just east of Sumba. Westward from here, a series of younger, shallower, 3-km-deep trenches (Timor Trench, Tanimbar Trench, and Seram Trench) extend eastward following the tightly curved Banda Arc (Milsom et al. 1992). The newer arcs evolved with the arrival at the subduction zone of the less-dense continental mass of Australia.

Figure 2.3. The current plates and plate boundaries of the world.

From Derry 1980 with permission from Mining Journal Books Ltd.

Legends:

A. Transcurrent plate boundary. No loss of material as plates slip along each other in opposite direction; for example, San Andreas Fault in western America.

B. Tensional plate boundary. Addition of material through rift, which allows new magma to push up a trench. This new material builds up, pushing the two sides apart. Most often found beneath the oceans, for example, the Mid-Atlantic Trench.

C. Collisional plate boundary, (a) Mountain building, as plate edges are pushed up, for example, the Himalayas, (b) Subduction zone. Material is lost as one plate is pushed under another, and is returned to the mantle. See figure 2.5 for details.

Figure 2.4. Categories of plate boundaries.

After Derry 1980.

Figure 2.5. Subduction zone and associated features.

After Hamilton 1979 with permission from the US Geological Survey and RePPProT 1989a.

A trench is formed on the seafloor at the physical point at which the crust is being subducted. A chain of islands known as the outer-arc or fore-arc islands, such as Rod and Tanimbar, may occur just behind this trench (between the trench and the volcanic island arc), by uplift of marine sediments. As the denser oceanic crust sinks down into the trench, sediments that have accumulated on the subducting seabed can be 'skimmed' (accreted) onto the lighter, overlying crust. Envisage pouring cream through the narrow opening of a jug. The skin on the cream does not always flow easily and bits accumulate on the lips of the opening - the outer-arc islands. If the sediments are accrued chaotically, the resulting rock mixture is called melange (fig. 2.5).

Figure 2.6. Seismic-reflection profiles across the Timor and Tanimbar sections of the Banda Arc.

After Hamilton 1979 with permission from the U.S. Geological Survey.

As the brittle oceanic crust and associated mantle (the lithosphere) is subducted into the mantle of the overriding plate, it undergoes extension, shearing, and compression. This causes earthquakes in a particular section of the mantle called the Benioff Zone (fig. 2.5). Increasing pressure from the heating and expansion of this newly introduced material causes volcanic outlets to form directly above the Benioff Zone, which then act as pressure valves. Another chain of islands therefore occurs parallel with and several hundred kilometres removed from the length of the trench, known as the inner volcanic arc (also called the inner orogenic arc or back-arc) islands, such as Lombok, Flores, and the Banda Islands. The rocks are of a particular kind, confined only to islands with a Benioff Zone beneath: calc-alkaline basalts and andesites (LTA-72 1982).

Depressions in the seabed between the inner volcanic arc and the outer-arc are known as fore-arc basins. These fore-arc basins form seas such as the Sawu Sea or the 7000-m Weber Deep (figs. 2.5 and 2.6). A series of back-arc basins may also be developed on the other side of the inner volcanic arc. In contrast to these depths, the Arafura Sea on the Australian continental shelf is generally between 50 m and 80 m deep, with the shelf edge from 120 m to 200 m deep (Jongsma 1970). These island arcs and deep sea basins are the most characteristic geological features of NT&M (figs. 2.1 and 2.6).

As new crust is formed in one place (rifts), old crust is thus recycled back into the mantle elsewhere. Continental crustal fragments that may be carried on slabs of lithosphere on these plates therefore slip and slide across the face of the earth, bumping into each other. This continual fusion and fragmentation of the continents has been called the 500 million year waltz of the continents (Davidson 1992).

Geological Origins of Nusa Tenggara and Maluku

In fact, we need go back only about 300 million years to understand the origins and the future of NT&M. Indeed, many of the islands appeared only within the last 1 to 10 million years (table 2.2; fig. 2.7).

In the Permian (Palaeozoic), 245-290 million years ago, only one super-continent called Pangaea (or Pangea) existed on Earth. The shallow Tethys Sea, an arm of the single ocean (Panthalassa), protruded into east Pan-gaea, bounded on the north by the nascent Asian block and on the south by the Australian continental margin. Some 150-215 million years ago, during the Mesozoic, the single continent was split further by the expanding Tethys Sea into two component continents of Laurasia and Gondwanaland: Laurasia included present-day North America, Europe, and Asia; Gondwanaland included present-day Arabia, South America, Africa, Australia, New Guinea, Antarctica, India, New Zealand, and parts of Southeast Asia. A subduction zone may have developed simultaneously along the southern margin of the Asian block (southern coast of Laurasia), forming the precursor to the Java Trench (the Java Trench is shown in figure 2.1). There followed a general move northwards of Gondwanaland, and the Indian-Australian-Antarctic section drifted northwards towards the subduction zone. One hundred million years ago, India broke off as a separate subcontinent to head north independently, hitting Asia 40 million years later in the Tertiary. West Indonesia started to develop its modern shape at this time; the blocks from which it is assembled are also generally assumed to originate from Gondwanaland (Burrett et al. 1991; fig. 2.7).

The Arafura Sea, the shallow continental shelf off Australia on the edge of Gondwanaland, was formed about 95 million years ago in the Cretaceous. Australasia and Antarctica broke apart soon after. While Antarctica moved to its present position, Australia, New Guinea, and the Arafura Sea drifted 4000 km across the Tethys Sea northwards towards the subduction zone below the southern edge of the Eurasian Plate. With oceanic crust disappearing beneath the Eurasian Plate at the average rate of 8 mm/year, the northwest margin of the Australian continental crust finally collided with the proto-Banda Arc only 20-25 million years ago (an arc-continent collision), initially in the region of New Guinea. Because continental crust is less dense than oceanic crust, the Australian continental margins started to interfere with the subduction zone at the southern edge of the Sunda Shelf, along the proto-Banda Arc east of Sumba, creating major tectonic uplift in the mid-Tertiary. Most of the inner volcanic arc and outer-arc islands of NT&M did not exist before the mid-Tertiary (table 2.2).

Figure 2.7. Plate movements affecting the geological evolution of Nusa Tenggara and Maluku.

After N. Duhig in Burrett et al. 1991, with permission from C. Burrett.

While the Banda Arc was being formed along one edge of the Indo-Aus-tralian Plate, the northern margins were in contact with the northwest-moving Pacific Plate. This westward movement of the Pacific Plate during the Miocene (10-25 million years ago), developed a different type of plate boundary, a sideways-slipping or transcurrent plate boundary (fig. 2.4) called the Sorong Fault. This is a particularly important feature in present-day Maluku, and is discussed later in this chapter. The still-active fault sliced continental crustal fragments, such as Sula and Obi, off the Irian continental margin and carried them westwards. It also caused the eastern end of the Banda Arc to bend sharply anticlockwise in a U-turn whose diameter is only 700 km (Hamilton 1979). This event, described by Whitten et al. (1987) as the most dramatic event in Indonesian geological history, trapped the old Cretaceous oceanic crust behind the Banda Arc to form the 5000-m deep Banda Sea (a normal depth for an ocean floor of this age). East of the Sorong Fault, another subduction zone developed during the early Miocene (25 million years ago), with the Indo-Australian Plate subducting beneath the Pacific Plate. It is from here that the islands of north Maluku later originated.

By the mid-Tertiary, therefore, all pieces were in place for the development of NT&M: the Sunda Arc and the Banda Arc to the southwest, and the Sorong Fault moving westwards across the centre.

Evolution of Nusa Tenggara and Maluku

The evolution of individual islands within NT&M is complex and still under debate. However, it is possible to classify the islands into types (adapted from RePPProT 1989a) based on the differentiation of islands into oceanic and continental islands. Oceanic islands are islands rising from the ocean floor in isolation and are not part of the continental crust. In NT&M, these oceanic islands, originating from both the inner volcanic arc and the outer-arc, are younger than mid-Miocene (15 Ma). Most of them appeared above sea level during the late Miocene-Pliocene (Audley-Charles 1993). Continental islands are part of a continental mass but situated on the continental shelf, thereby separated from the mainland at present by sea. Fragments of continental material that have been torn off the continental mass and separated from it are called continental crustal fragments, island rafts, or microcontinents.

The island types present in NT&M are:

• inner volcanic arc islands;

• outer-arc islands;

• continental crustal fragments;

• composite islands (composed of two or more islands from different sources);

• true continental islands;

(table 2.3). Apart from illustrating the evolution of each island as known at present, table 2.3 should aid biogeographical analysis.

Islands are, above all else, transitory, and whereas oceanic islands rise from the seabed and continental crustal fragments move away from the parent continental block, all islands erode, subside, and disappear beneath the sea (Amos 1980).

The Inner Volcanic Arc Islands: Sunda Arc and Banda Arc. The inner volcanic arc islands are some of the simplest geological structures within this complex region, and are certainly simpler than the outer-arc islands. From west to east, through West Nusa Tenggara (WNT), ENT, and East Timor to Maluku, the main inner volcanic arc islands are: Lombok and Sumbawa, Komodo, Flores, Solor, Adonara, Lomblen, Pantar, Alor, Atauro (off northeast Timor), Wetar, Romang, Damar, Teun, Nila, Serua, Manuk, and the Banda Islands. (See appendix 1 for all islands within each island group and alternative spellings.)

The inner volcanic arc islands are basically young oceanic volcanic islands, often ringed by reef limestones or by other sedimentary material that has eroded from the main body of the island and built up between the tongues of lava and other extrusions (fig. 2.8). Lombok and Sumbawa are the easternmost islands of the Sunda Arc. The discontinuity between the Sunda Arc and the Banda Arc is marked by the Sumba Fracture separating Sumba and Flores from Sumbawa (Hutchison 1992). In general, the origins or basal materials of these islands become progressively younger from west to east, following the evolution of the Banda Arc eastward from the Sumba Fracture (table 2.3a). In fact, although few islands occur in the Inner Banda Arc from Wetar through to Banda, many more young, growing, submarine volcanoes occur along the eastern end of the arc. These follow a submarine ridge that rises about 125 km above the Benioff Zone of the Timor Trench subduction system (Hamilton 1979). The active Mt. Api and the surrounding islands comprising the Banda Islands are the ruins of one larger volcano, whose destructive final explosion in prehistory must have rivalled that of Tambora and Krakatau (Krakatoa).

Within the inner volcanic arc islands, two basic hill or mountain land forms occur, older highly eroded Tertiary (Mio-Pliocene) volcanoes with dissected high narrow ridges, and younger Quaternary active volcanoes with classical conical shapes. This is an example of the development of a sequence of inner volcanic arc ridges as a subduction zone moves forward. For example, in the Tertiary, an inner volcanic arc grew along what is now the southern edge of Lombok and Sumbawa (table 2.3a). The eroded remains of these andesitic and basaltic volcanoes can be seen today in, for example, Mt. Mareje (716 m asl) near Mataram, Lombok. These volcanoes may have intruded through Tertiary sedimentary rocks. Alternatively, sedimentary rocks may have developed unconformably around the volcanic lava. Examples of rocks lying unconformably on other rocks are coral reefs that form around a volcano's coastline or between lava flows that entered the sea, or eroded material that collects at the base of onshore and offshore slopes.

1 Numbers refer to time of event (millions of years ago).

Sources: 1 Audley-Charles 1975; 2 Hamilton 1979; 3 Auffenberg 1980; 4 Abbott and Chamalaun 1981; 5 Hall et al. 1988a; 6 Hall et at. 1988b; 7 RePPProT 1989a; 8 Smet et al. 1989; 9 Hall and Nichols 1990; 10 Burret et al. 1991; 11 Charlton et al. 1991; 12 Harris 1991; 13 Pirazzoli et al. 1991; 14 Audley-Charles 1968; 15 Barber et al. 1985; 16 Milsom 1979; 17 Audley-Charles 1993; 18 Sigurdsson and Carey 1992; 19 Hutchison 1992; 20 Jongsma 1970; 21 Fortuin and de Smet 1991; 22 van Marie 1989; 23 Nichols et al. 1991.

Considerable recent uplift has occurred in the southern regions of Lombok and Sumbawa. Limestones and eroded conglomerates from the older Tertiary volcanoes have formed the coastal cliffs and rocky shores that can be seen, for example, near Kuta and Blongas in southern Lombok. The uplands south of Taliwang, southwest Sumbawa, are uplifted coral limestone abutting volcanic andesitic rocks to the south and southeast (Fenco Consultants 1981d). During the Quaternary, another inner volcanic arc developed to the north. Lombok was therefore probably once two volcanic massifs, a northern Quaternary block and a southern Tertiary block both rising from the seabed, with their emerged slopes separated by a shallow sea. This shallow sea was subsequently filled by eroded material from the slopes of the volcanoes and now forms the agriculturally rich, flat, central plains (B. Levitt pers. comm.).

Box 2.2. Why are NT&M volcanoes cone-shaped?

The classical volcano shape is the cone, as seen throughout the inner volcanic arc islands. These are called stratovolcanoes, made of alternating layers of lavas and pyro-clastic rock, mostly of andesitic composition.

Magmas vary with respect to their silicon dioxide concentration [S1O2], viscosity, and gas content such that:

As the andesitic lava flows from stratovolcanoes have medium viscosity, so that they do not normally flow more than a few kilometres, they produce the classic steep-sided cone.

Rhyolitic magmas may be produced by partial melting of the continental crust, as happens when the Australian continental crust is absorbed into the Timor Trench. These acidic, high-[Si02] rocks are therefore very viscous, withstanding high gas pressures and erupting rarely. If a rhyolitic magma chamber is below a stratovolcano, the pressures are such that, once an eruption begins, the magma chamber blows out completely, leaving an empty hole into which the stratovolcano collapses, producing a crater or caldera several kilometres wide. The main emissions are pyroclastics: ashes, in vast quantities and covering immense areas, and pumice (Driessen and Dudals 1989).

The type of magma can therefore have an important effect on subsequent soil development.

Figure 2.8. Geological map of Nusa Tenggara and Maluku.

From RePPProT 1989a.

Komodo is the exception among the mainly Cenozoic (Tertiary) volcanic islands. Its history extends back to the late Mesozoic, according to potassium-argon isotope dating of igneous rock samples taken immediately below and above a fossil wood zone (Auffenberg 1980). The western half of Komodo is formed on a Jurassic volcanic mass (145-210 million years ago), flanked by the expected sedimentary rocks (lenses of tuffs, sandstones, and conglomerates with intercalated limestones, sandy shales, and clays). The eastern part of the island has an early to mid-Tertiary (Eocene) volcanic complex, again flanked with steeply tilted beds of coralline limestone. Both Padar and Rinca are composed of the same limestone (Rinca also has some volcanic origin) (Auffenberg 1980, 1981). The numerous small islands between these and Flores are all uplifted coral limestone.

At one time, Flores was also thought to be a geologically old island that existed prior to the Miocene. It is now thought to have its origins in the late Tertiary (Mio-Pliocene), like parts of Lombok and Sumbawa, and that, like Lombok, Sumbawa, and more ancient Komodo, this initial volcanism was submarine (Burrett et al. 1991). Flores is now a particularly unstable area because of the reactionary back-arc thrust fault that has developed to the north of Flores and Wetar. This is in response to the arc-continent collision at the Timor Trench to the south of the islands (all the present trenches are shown in figure 2.1). This means that these islands are, in effect, being thrust northwards towards the Sunda Shelf and the Banda Sea (Carlile and Mitchell 1994). Presently, Flores has 14 active volcanoes, with the most recent activity being generally in eastern Flores and the higher mountains ranging from 1900 m asl to 2100 m asl (Carson and Abdullah 1976; see table 2.8). Two main sedimentary basins occur in west Flores, one