The Archaeology of Drylands: Living at the Margin 9780203165737

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THE ARCHAEOLOGY OF DRYLANDS The One World Archaeology (OWA) series stems from conferences organized by the World Archaeological Congress (WAC), an international non-profit making organization, which provides a forum of debate for anyone who is genuinely interested in or has a concern for the past. All editors and contributors to the OWA series waive any fees they might normally receive from a publisher. Instead all royalties from the series are received by the World Archaeological Congress Charitable Company to help the wider work of the World Archaeological Congress. The sale of OWA volumes provides the means for less advantaged colleagues to attend World Archaeological Congress conferences, thereby enabling them to contribute to the development of the academic debate surrounding the study of the past. The World Archaeological Congress would like to take this opportunity to thank all editors and contributors for helping the development of world archaeology in this way.

ONE WORLD ARCHAEOLOGY Series Editor: (Volumes 1–37): Peter J.Ucko Academic Series Editors (Volume 38 onwards): Martin Hall and Julian Thomas Executive Series Editor (Volume 38 onwards): Peter Stone

1. What is an Animal?, T.Ingold (ed.) 2. The Walking Larder: Patterns of domestication, pastoralism and predation, J.CluttonBrock 3. Domination and Resistance, D.Miller, M.J.Rowlands and C.Tilley (eds) 4. State and Society: The emergence and development of social hierarchy and political centralization, J.Gledhill, B.Bender and M.T.Larsen (eds) 5. Who Needs the Past? Indigenous values and archaeology, R.Layton (ed.) 6. The Meaning of Things: Material culture and symbolic expression, I.Hodder (ed.) 7. Animals into Art, H.Morphy (ed.) 8. Conflict in the Archaeology of Living Traditions, R.Layton (ed.) 9. Archaeological Heritage Management in the Modern World, H.F.Cleere (ed.) 10. Archaeological Approaches to Cultural Identity, S.J.Shennan (ed.) 11. Centre and Periphery: Comparative studies in archaeology, T.C.Champion (ed.) 12. The Politics of the Past, P.Gathercole and D.Lowenthal (eds) 13. Foraging and Farming: The evolution of plant exploitation, D.R.Harris and G.C.Hillman (eds) 14. What’s New? A closer look at the process of innovation, S.E. van der Leeuw and R.Torrence (eds) 15. Hunters of the Recent Past, L.B.Davis and B.O.K.Reeves (eds) 16. Signifying Animals: Human meaning in the natural world, R.G.Willis (ed.)

17. The Excluded Past: Archaeology in education, P.G.Stone and R.MacKenzie (eds) 18. From the Baltic to the Black Sea: Studies in medieval archaeology, D.Austin and L.Alcock (eds) 19. The Origins of Human Behaviour, R.A.Foley (ed.) 20. The Archaeology of Africa: Food, metals and towns, T.Shaw, P.Sinclair, B.Andah and A.Okpoko (eds) 21. Archaeology and the Information Age: A global perspective, P.Reilly and S.Rahtz (eds) 22. Tropical Archaeobotany: Applications and developments, J.G.Hather (ed.) 23. Sacred, Sites, Sacred Places, D.L. Carmichael, J.Hubert, B.Reeves and A.Schanche (eds) 24. Social Construction of the Past: Representation as power, G.C.Bond and A.Gilliam (eds) 25. The Presented Past: Heritage, museums and education, P.G.Stone and B.L.Molyneaux (eds) 26. Time, Process and Structural Transformation in Archaeology, S.E.van der Leeuw and J.McGlade (eds) 27. Archaeology and Language I: Theoretical and methodological orientations, R.Blench and M.Spriggs (eds) 28. Early Human Behaviour in the Global Context, M.Petraglia and R.Korisettar (eds) 29. Archaeology and Language II: Archaeological data and linguistic hypotheses, R.Blench and M.Spriggs (eds) 30. Archaeology and Anthropology of Landscape: Shaping your landscape, P.J.Ucko and R.Layton (eds) 31. The Prehistory of Food: Appetites for Change, C.Gosden and J.G.Hather (eds) 32. Historical Archaeology: Back from the edge, P.P.A.Funari, M.Hall and S.Jones (eds) 33. Cultural Resource Management in Contemporary Society: Perspectives on managing and presenting the past, F.P. MacManamon and A.Hatton (eds)

34. Archaeology and Language III: Artefacts, languages and texts, R.Blench and M. Spriggs (eds) 35. Archaeology and Language IV: Language change and cultural transformation, R.Blench and M.Spriggs (eds) 36. The Constructed Past: Experimental archaeology, education and the public, P.G.Stone and P.Planel (eds) 37. Time and Archaeology, T.Murray (ed.) 38. The Archaeology of Difference: Negotiating cross-cultural engagements in Oceania, R.Torrence and A.Clarke (eds) 39. The Archaeology of Drylands: Living at the margin, G.Barker and D.Gilbertson (eds)

THE ARCHAEOLOGY OF DRYLANDS Living at the margin

Edited by Graeme Barker and David Gilbertson

London and New York

First published 2000 by Routledge 11 New Fetter Lane, London EC4P 4EE Simultaneously published in the USA and Canada by Routledge 29 West 35th Street, New York, NY 10001 Routledge is an imprint of the Taylor & Francis Group This edition published in the Taylor & Francis e-Library, 2005. “To purchase your own copy of this or any of Taylor & Francis or Routledge's collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” © 2000 Selection and editorial matter, Graeme Barker and David Gilbertson; individual chapters, the contributors All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data The archaeology of drylands: living at the margin/[edited by] Graeme Barker and David Gilbertson. p. cm. (One world archaeology; 39) Includes bibliographical references and index. 1. Social archaeology. 2. Landscape archaeology. 3. Human ecology. 4. Deserts—History. 5. Land settlement —History. 6. Land settlement patterns, Prehistoric—History. 7. Arid regions agriculture—Social aspects—History. 8. Climatic changes—History. I. Barker, Graeme. II. Gilbertson, D.D. III. Series. CC72.4.A735 2000 930.1–dc21 00–038257 ISBN 0-203-16573-X Master e-book ISBN

ISBN 0-203-26029-5 (Adobe e-Reader Format) ISBN 0-415-23001-2 (Print Edition)

Contents List of figures List of tables List of contributors Series editors’ foreword Preface Part I Introduction 1 Living at the margin: themes in the archaeology of drylands Graeme Barker and David Gilbertson 2 The dynamic climatology of drylands Greg Spellman Part II Southwest and Central Asia 3 The decline of desert agriculture: a view from the classical period Negev Steven A.Rosen 4 Farmers, herders and miners in the Wadi Faynan, southern Jordan: a 10,000-year landscape archaeology Graeme Barker 5 Differing strategies for water supply and farming in the Syrian Black Desert Paul Newson 6 Irrigation agriculture in Central Asia: a long-term perspective from Turkmenistan Mark Nesbitt and Sarah O’Hara Part III Sahara and Sahel 7 Conquests and land degradation in the eastern Maghreb during classical antiquity and the Middle Ages Jean-Louis Ballais 8 Success, longevity, and failure of arid-land agriculture: Romano-Libyan floodwater farming in the Tripolitanian pre-desert David Gilbertson, Chris Hunt and Gavin Gillmore 9 Twelve thousand years of human adaptation in Fezzan (Libyan Sahara) David Mattingly 10 Farming and famine: subsistence strategies in Highland Ethiopia Ann Butler and A.Catherine D’Andrea

ix xiii xv xxv xxvii

3 18

44

62

85

101

121

133 156 174

Part IV Eastern and southern Africa 11 Engaruka: farming by irrigation in Maasailand, c.AD 1400–1700 John E.G.Sutton 12 The agricultural landscape of the Nyanga area of Zimbabwe Robert Soper 13 Fifteenth-century agropastoral responses to a disequilibrial ecosystem in southeastern Botswana John Kinahan 14 Islands of intensive agriculture in African drylands: towards an explanatory framework Mats Widgren Part V North and Central America 15 Prehistoric agriculture and anthropogenic ecology of the North American Southwest Paul E.Minnis 16 The role of maguey in the Mesoamerican tierra fría: ethnographic, historic and archaeological perspectives Jeffrey R.Parsons and J.Andrew Darling Part VI Europe 17 Traditional irrigation systems in dryland Switzerland Anne Jones and Darren Crook 18 Desertification, land degradation and land abandonment in the Rhône valley, France Sander van der Leeuw Index

195 214

227

246

264

280

307

327 346

Figures 1.1 1.2 1.3 1.4 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 3.1 3.2 3.3 3.4 3.5 3.6 3.7 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 5.1

The world map of drylands A Roman-period fortified farm, northwest Libya The location of the case studies in this volume Drowning in drylands?—two vehicles sunk in a flash-flood Thermal regimes in two dryland locations: Aswan, Egypt and Jacobabad, Pakistan Mean monthly relative humidity at four locations The rainshadow effect leading to aridity The Hadley Cell circulation of the tropical northern hemisphere The structure of the trade wind atmosphere The interaction between the subtropical westerly flow and the tropical easterlies leading to the creation of Saharan depressions The monthly progression of the East African Low-Level Jet Core The tracks of Sudano-Saharan depressions over the Sahara Terraced dam system in the central Negev The wine press at Shivta (Subeita) Sketch of the Byzantine town of Shivta (Esbeita or Subeita) Map of the general settlement system of the central Negev during the Late Byzantine and Early Islamic periods View of the Byzantine town of Avdat (looking north) Elaborate raised field and dam system on Nahal Lavan The early Islamic village of Sede Boqer in the central Negev The location of Wadi Faynan within its region Looking northeast across part of the ancient field system to Khirbet Faynan The survey area of the Wadi Faynan Landscape Survey Ethnoarchaeological survey: the typical site of a winter bedouin tent in Wadi Faynan The settlement locations of the first farmers in the Wadi Faynan Part of the Wadi Faynan field system WF4, showing the early bronze age and the classical landscapes A field system on the northern side of the Wadi Faynan A field map of part of the field system WF4 The distribution of copper through sediments accumulated behind the Khirbet Faynan barrage Section through a Roman-period water conduit channel The Hauran and the Harra regions of Syria

3 4 5 7 22 24 25 26 28 30 32 34 45 46 47 48 49 50 52 63 64 65 67 70 72 73 76 77 79

86 5.2 Plan of the Roman-period settlement of Ad-Diyatheh and its water channels and field systems 5.3 The Roman-period settlement of Ad-Diyatheh and its channel walls 5.4 Plan of the main irrigated zone along the Wadi Sham by the Romanperiod settlement of al-Namara 5.5 View of the main irrigated zone along the Wadi Sham at al-Namara 5.6 Canal 3 at al-Namara, viewed from the east 5.7 The ancient reservoir at Qasr Burqu’ 5.8 Air photograph of Qasr Burqu’ and its reservoir 6.1 Turkmenistan, showing locations mentioned in Chapter 6 6.2 Bronze and iron age settlement in the Merv oasis, Turkmenistan 7.1 The eastern Maghreb, showing locations mentioned in Chapter 7 7.2 Flood deposits at Ksar Rhilane (Tunisia) 7.3 The modern Roman aqueduct crossing Wadi Bou Jbib, Carthage 7.4 Holocene terrace of Wadi Chéria-Mezeraa (Algeria) 7.5 Holocene terraces in the Wadi el Akarit (Tunisia) 8.1 Tripolitania, northwest Libya, showing the principal landforms and settlements, and the location of the UNESCO Libyan Valleys Survey 8.2 Romano—Libyan floodwater farming in the Wadi Gobbeen 8.3 Simplified distribution of early Romano—Libyan farms 8.4 A Romano—Libyan fortified farm (gasr) and its satellite buildings at Ghirza 8.5 Model of Romano—Libyan agriculture 8.6 Walls in the desert: wall systems in the Wadi Mimoun 9.1 Map showing the location of the Fezzan and the area of most detailed survey around Germa 9.2 The major climatic fluctuations of the Holocene in the Libyan Sahara 9.3 The settlement of Germa (ancient Garama), the capital of the Garamantes 9.4 Schematic cross-section of a foggara 9.5 Model of the neolithic landscape around Germa 9.6 Model of the evolved Garamantian landscape around Germa 9.7 Model of the medieval landscape around Germa 9.8 Model of hypothetical future direction of settlement and farming in Fezzan 10.1 Map of Ethiopia, showing Adi Ainawalid in Tigrai province 10.2 Residential compound near fields, Adi Ainawalid 10.3 Intercropped bread and durum wheats near Mai Kayeh, Tigrai 10.4 Harvesting grasspea by hand uprooting, Adi Ainawalid 10.5 First threshing of teff, Adi Ainawalid 10.6 Winnowing teff, Adi Ainawalid

88 89 92 93 93 95 95 103 107 122 124 126 127 128 134 134 136 144 146 147 157 159 161 163 164 167 168 169 175 176 179 181 182 183

10.7 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12.1 12.2 12.3 13.1 13.2 13.3 13.4 14.1 14.2 14.3 14.4 14.5 14.6 15.1 15.2 15.3 15.4 15.5 15.6 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9

Grain storage jars, Adi Ainawalid The Rift Valley and Crater Highlands of northern Tanzania Engaruka and the Rift Valley escarpment The Engaruka escarpment from the east Engaruka south fields Grid of feeder furrows and levelled field plots The support for the ‘great northern’ canal The embanked causeway of the ‘great northern’ canal An angular cairn Sonjo: wooden house with thatch dome Location of the Nyanga area, Zimbabwe Terraced hillsides in the Nyanga lowlands Vertical aerial photograph of cultivation ridges The regional setting of Letsibogo, southeastern Botswana The distribution and linkage of Khami period sites at Letsibogo Plan and section of Letsibogo Site 125 Distribution of soil nutrient values at Letsibogo Site 125 Eastern and southern Africa, showing sites mentioned in Chapter 14 An intensively cultivated landscape at Kwermusl Preparing the field at Kwermusl Piles of manure from stalled cattle, Mama Issara An irrigation channel above Tot in Marakwet, Kenya An irrigation canal under repair above Chesoi, Marakwet The North American Southwest Prehistoric Hohokam communities and irrigation systems in the Phoenix basin of the Salt river Aerial photograph of prehistoric trincheras (checkdam) fields near Casas Grandes, Chihuahua, Mexico Gridded gardens of fields near Safford, Arizona A rock mulch field near Casas Grandes, Chihuahua, Mexico An excavated rock pile from the field shown in Figure 15.5 Middle America, showing the approximate extent of the tierra fría Field of cultivated magueys Castrating a mature maguey plant Spinning maguey fibre Pre-columbian spindle whorls used for spinning maguey fibre Use of modern iron scraper for extracting maguey fibre Examples of pre-columbian trapezoidal tabular basalt scrapers Experimental use of pre-columbian trapezoidal tabular basalt scraper A pre-columbian scraper plane

184 196 197 198 200 200 201 202 203 212 215 216 219 229 233 234 236 248 251 252 252 253 254 265 267 268 269 270 270 281 282 286 290 291 293 294 295 295

16.10 17.1 17.2 17.3 17.4 17.5 17.6 18.1 18.2 18.3 18.4 18.5 18.6 18.7

Modern iron scraper and pre-columbian obsidian scrapers The Valais canton, Switzerland, showing places mentioned in Chapter 17 Distribution of agricultural land in Vernamiège during the 1960s The Grand Bisse de Lens The irrigation sectors in Vernamiège Distribution of water during the first tour from the bisses of Vernamiège, 5th May-8th June 1964 A tessel, used by members of the consortage of the Grand Bisse de Lens The middle and lower Rhône valley, showing the progress of Roman colonization Settlement trends in the middle and lower Rhône valley, 50 BC-AD 600 The persistence of settlements in the middle and lower Rhône valley through different occupation periods GIS maps of the Haut Comtat The three levels of the investigation into modern-day urban—rural dynamics in southern France Relations between cities, individual communes and their contexts Differences in context occurring among towns of similar and/or different sizes in the Haut Comtat

296 308 309 313 317 318 320 329 331 333 335 338 339 340

Tables 2.1 2.2 2.3 2.4 2.5 2.6 6.1 6.2 7.1 8.1 10.1 10.2 13.1 13.2 16.1 17.1 17.2 17.3 18.1 18.2 18.3

The regional distribution of world drylands Rainfall regimes at selected dryland stations Estimates of the land area of arid lands Mean relative humidity at various isobaric levels in the Sahara and the Arabian peninsula Seven ITCZ zones The extent and severity of desertification Simplified chronological chart of prehistoric settlement in Turkmenistan Simplified chronological chart of settlement in the Merv oasis in the historic period Morphoclimatic evolution in the eastern Maghreb during the later Holocene Farm products of the Tripolitanian pre-desert, first to fifteenth centuries AD Crops cultivated at Adi Ainawalid, Tigrai, Ethiopia Crops no longer cultivated at Adi Ainawalid, Tigrai, Ethiopia Selected radiocarbon measurements from Letsibogo Faunal taxa from Letsibogo Site 125 The prehispanic chronology of central Mexico Approximate numbers of named irrigators using the Grand Bisse de Lens ‘aqueductis communi’ in 1457 Examples of tours, with the number of droits and sequence of irrigation hours Examples of bisse disputes Evolution of the ‘nature-culture’ debate over the last thirty years The different approaches of the historical and natural sciences to the reconstruction of the past The opposition between analytical and integrative approaches in research

19 19 20 23 29 35 112 113 122 141 178 186 231 237 283 314 316 321 341 342 342

Contributors JEAN-LOUIS BALLAIS is Professor of Physical Geography at the Université de Provence, Aix-en-Provence (France). His principal research interests focus on Holocene Mediterranean erosion (he co-directed the study of erosion and geosystems history in classical antiquity and the Middle Ages for the EU-funded Archaeomedes project described in Chapter 18), and present-day erosion, desertification and land degradation in the south of France and in the Maghreb. Relevant recent publications include: ‘Aeolian activity, desertification and the “Green Dam” in the Ziban range, Algeria’, in A.C.Millington and K.Pye (eds) Environmental Change in Drylands: Biogeographical and Geomorphological Perspectives: 177–98, Chichester, John Wiley and Sons 1994; ‘The south of France and Corsica’, in A.J.Conacher and M.Sala (eds) Land Degradation in Mediterranean Environments of the World: 29–39, Chichester, John Wiley and Sons 1998; and (with J.-C.Meffre) Le Plan de Dieu (NordVaucluse). Géoarchéologie et Histoire d’un Paysage Anthropisé, Etudes Vauclusiennes 15, 1996. (Institutional address: Institut de Geographic, ‘Université de Provence (Aix-Marseiile I), 29 Avenue Robert Schuman, 13621 Aix-en-Provence, France) GRAEME BARKER (BA, PhD University of Cambridge) taught prehistoric archaeology at the University of Sheffield (1972–84) and was then Director of the British School at Rome (1984–88), before taking up his appointment as Professor of Archaeology at the University of Leicester (UK), where he is currently Dean of the University Graduate School. His principal research interests have been in the archaeology of subsistence and agriculture, with a special focus first on archaeozoology but later in landscape archaeology. He has conducted fieldwork in Italy, Mozambique, and the former Yugoslavia, and has directed inter-disciplinary field projects in Italy, Libya and currently in Jordan. His publications include: Landscape and Society: Prehistoric Central Italy, London, Academic Press 1981; (with R.Hodges) Archaeology and Italian Society, Oxford, British Archaeological Reports 1981; Prehistoric Communities in Northern England. Sheffield, University of Sheffield 1981; Prehistoric Farming in Europe, Cambridge, Cambridge University Press 1985; (with C.S.Gamble) Beyond Domestication in Prehistoric Europe, London, Academic Press 1985; (with J.Lloyd) Roman Landscapes: Archaeological Survey in the Mediterranean Region, London, British School at Rome 1991; A Mediterranean Valley: Landscape Archaeology and Annales History in the Biferno Valley, London, Leicester University Press 1985 (two volumes); (with D.Gilbertson, B.Jones and D. Mattingly) Farming the Desert: The UNESCO Libyan Valleys Archaeological Survey. Volume One: Synthesis, Volume Two: Gazetteer and Pottery, Paris, UNESCO 1996; (with T.Rasmussen) The Etruscans, Oxford, Blackwells 1998; The Companion Encyclopedia of Archaeology, London, Routledge 1999; and (General editor with D.Mattingly) Mediterranean Landscape Archaeology, Oxford, Oxbow 2000 (five volumes). He was elected a

Fellow of the British Academy in 1999. (Institutional address: the Graduate School, University of Leicester, Leicester LE1 7RH, UK) ANN BUTLER is an Honorary Lecturer at the Institute of Archaeology, University College London, with a BSc degree in Botany (London University), an MA in Archaeology (Manchester University) and a PhD in Archaeology (London University). Her research interests centre on legumes as a human resource in the temperate Old World, and include ancient diet and nutrition, plant domestication and crop dispersals, traditional agriculture and sustainable farming. Her fieldwork has been conducted in Europe, Southwest Asia and Highland Ethiopia. Her current research focuses on the evidence for the domestication and exploitation of legume crops. Her recent publications include: ‘Pulse agronomy: traditional systems and implications for early cultivation’, in P.C.Anderson (ed.) Préhistoire de l’Agriculture: 67–78, Paris, CNRS 1998 and ‘Traditional seed cropping systems in the temperate Old World: models for antiquity’, in C.Gosden and J.Hather (eds) The Prehistory of Food: 473–77, London, Routledge 1999. (Institutional address: Institute of Archaeology, University College London, 31–34 Gordon Square, London WC1H OPY, UK) A. CATHERINE D’ANDREA is an Associate Professor of Archaeology at Simon Fraser University, British Columbia, Canada. She completed a BSc in Anthropology at the University of Toronto, an MSc in Bioarchaeology at University College London and a PhD in Anthropology at the University of Toronto. Her research interests include palaeoethnobotany, ethnoarchaeology and early agrarian societies in Africa and the Far East. She is currently conducting ethnoarchaeological and palaeoethnobotanical research in northern Ethiopia, as well as collaborating on an excavation in northern Ghana. Her recent publications include: ‘The dispersal of domesticated plants into northeastern Japan’, in C.Gosden and J.Hather (eds) The Prehistory of Food: 163–83, London, Routledge 1999 and (with D.E.Lyons, Mitiku Haile and E.A. Butler) ‘Ethnoarchaeological approaches to the study of prehistoric agriculture in the Ethiopian Highlands’, in M.van der Veen (ed.) The Exploitation of Plant Resources in Ancient Africa: 101–22, New York, Plenum Publishing Corporation 1999. (Institutional address: Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6) DARREN CROOK is currently a Postdoctoral Fellow in the Department of Geography, University of Liverpool, working on historical impacts of land use and climate on hydrology in a pre-alpine landscape, funded by the Leverhulme Foundation. He graduated with a BSc in Human Ecology from the University of Huddersfield. His PhD, also from the University of Huddersfield, dealt with the sustainability of the bisse mountain irrigation system in the Valais, Switzerland. Publications from this include: (with A.M. Jones) ‘Traditional irrigation and its importance to the tourist landscape of Valais, Switzerland’, Landscape Research 24 (19) 1999:49–65 and (with A.M. Jones) ‘Traditional water management in a developed world context: an example from the Valais, Switzerland’, Mountain Research and Development 19 (2) 1999:79–99. (Institutional address: Department of Geography, University of Liverpool, Roxby Building, Liverpool L69 3BX, UK) J.ANDREW DARLING completed his PhD in Anthropology at the University of Michigan in 1998 and is currently an archaeologist for the Gila River Indian

Community and Board Member for the Mexico-North Research Network, Cd. Chihuahua, Mexico. He has conducted fieldwork in Zacatecas, Mexico (1988-present), on the north coast of Peru (1989–90), in southeastern Hungary (1987) and the North American Southwest (1984–1987). His research interests include compositional studies, exchange, regional interaction and ritual in prehistoric and ethnographic complex societies, including parallel archival investigations on the development of American archaeology in Mexico during the early twentieth century. Significant publications include: ‘Anasazi mass inhumation and the execution of witches in the American Southwest’, American Anthropologist 100, 1993:1–21; (with M.Glascock) ‘Acquisition and distribution of obsidian in the north-central frontier of Mesoamerica’, in E.C.Rattray (ed.) Rutas de Intercambio en Mesoamerica, III Coloquio Pedro Posch Gimpera: 345–64, Mexico, D.F., Universidad Nacional Autonoma de Mexico 1998; ‘Trace element analysis of the Huitzila and La Lobera obsidian sources in the southern Sierra Madre Occidential, Mexico’, Journal of Radioanalytical and Nuclear Chemistry Articles 196 (2), 1995:243–52; and ‘Notes on obsidian sources of the southern Sierra Madre Occidental’, Ancient Mesoamerica 4, 1993:245–53. (Institutional address: Mexico-North Research Network, 16 de Septiembre #402, Cd. de Chihuahua, Chihuahua, Mexico CP 31020) DAVID GILBERTSON is Head of the School of Conservative Sciences at the University of Bournemouth (UK) and Distinguished Visiting Scholar in the Department of Geography and Environmental Studies at the University of Adelaide (Australia). He graduated in Environmental Sciences at the University of Lancaster and gained his PhD and DSc in Quaternary and Archaeological Geology from the University of Bristol. Previous appointments have included: a Senior Fulbright Scholar at the University of Arizona; the Directorship of the MSc Programme in Environmental Archaeology, and then Head of the Research School in Archaeology and Archaeological Science at the University of Sheffield, where he became Reader then Professor; Director of the Institute of Geography and Earth Science at the University of Wales, Aberystwyth; and Professorial Research Fellow, University College Northampton. In addition to dryland environments, past and present, his research interests include coastal geomorphology, environmental change and caves, and environmental archaeology in general. His principal publications include: (with R.D.S.Jenkinson) In the Shadow of Extinction: The Quaternary Geology and Palaeoecology of the Lake, Fissures, and Smaller Caves at Creswell Crags, Sheffield, University of Sheffield Monographs in Prehistory 1984; (with D.J.Briggs, and G.R.Coope) The Chronology and Environmental Framework of Early Man in the Upper Thames: A New Model, Oxford, British Archaeological Reports 1985; Run-Off Farming in Rural Arid Lands, Applied Geography Theme Volume 6 (1) 1986; (with G.Barker, B.Jones, and D.Mattingly) Farming the Desert: The UNESCO Libyan Valleys Archaeological Survey. Volume One: Synthesis, Volume Two: Gazetteer and Pottery, Paris, UNESCO 1996; and (with M.Kent and J.P.Grattan) The Outer Hebrides: The Last 14,000 Years, Sheffield, Sheffield Academic Press 1996. (Institutional addresses: School of Conservation Sciences, University of Bournemouth, Bournemouth BH12 5BB, UK, and Department of Geography and Environmental Studies, University of Adelaide, South Australia 5005)

GAVIN GILLMORE is Senior Lecturer in Earth Science at University College Northampton. His research interests include the application of fossil studies to palaeoenvironmental analysis, ecotoxicology of cave environments, and microfossil and stratigraphic studies of Quaternary sedimentary basins. He has worked extensively for oil exploration companies, producing many consultancy reports on Jurassic, Cretaceous and Tertiary-Quaternary microfossil assemblages. Some current papers include: (with M.Sperrin, P.Phillips and A.Denman) ‘Radon hazards, geology, and exposure of cave users: a case study and some theoretical perspectives’, Ecotoxicology and Environmental Safety 2000; (with K.A.Smith, and S.Sinclair) ‘Palaeoenvironmental and biostratigraphical significance of Ostracoda from the Milton Formation (Quaternary), Northamptonshire, UK’, Proceedings of the Geologists Association 2000; and (with T.Kjennerud and R.Kyrkjebø) ‘The reconstruction and analysis of palaeowater depths: a new approach and test of micropalaeontological approaches in the post-rift (Cretaceous to Quaternary) interval of the Northern North Sea’, in O.J.Martinsen and T.Dreyer (eds) Sedimentary Environments Offshore Norway—Palaeozoic to Recent, Oslo, Norwegian Petroleum Society Special Publication 2000. (Institutional address: School of Environmental Science, University College Northampton, Northampton NN2 7AL, UK) CHRIS HUNT is currently a Senior Lecturer in the Division of Geographical Sciences at the University of Huddersfield. His academic education led him from a degree in Geogaphy/Geology and an MSc in Micropalaeontology (Palynology) at the University of Sheffield to a PhD at Aberystwyth (Wales) on the Pleistocene history of an area in Somerset. He has published extensively in the area of environmental archaeology in Britain, Europe, North Africa and the Middle East. Recent publications include: (with G.Barker, D.D.Gilbertson, and D.Mattingly) ‘Romano-Libyan agriculture: integrated models’, in G.Barker, D.Gilbertson, B.Jones and D.Mattingly, Farming the Desert: The UNESCO Libyan Valleys Survey. Volume One: Synthesis: 265–90, Paris, UNESCO 1996; (with S.Campbell, J.Scourse and D.H.Keen) The Quaternary of South West England, Chichester, Chapman & Hall, Geological Conservation Review Series 14, 1998; and (with D.D.Gilbertson) ‘Context and impacts of ancient catchment management in Mediterranean countries: implications for sustainable resource use’, in D.Wheater and C.Kirby (eds) Hydrology in a Changing Environment, Volume II: 473– 83, Chichester, John Wiley and Sons 1998. (Institutional address: Division of Geographical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK) ANNE JONES is currently a Senior Lecturer in the Division of Geographical Sciences at the University of Huddersfield, and Head of Division. She graduated with a BSc in Geography from Queen Mary College (University of London) and then obtained her DPhil thesis at the University of Oxford studying immigrant communities in Marseille, France. Subsequently, she has held posts at the Open University, Liverpool University and Cambridgeshire College of Arts and Technology (now Anglia Polytechnic University). Her research interests focus around the inter-relationship between demography and the allocation of scarce resources in marginal environments in alpine Europe, the Mediterranean and Africa. Her principal publications include: ‘Exploiting a marginal European environment: population control and resource management under

the Ancien Regime’, Journal of Family History 16 (4) 1991:363–79; (with C.O.Hunt) ‘Walls, wells and water supply: aspects of the cultural landscape of Gozo, Maltese Islands’, Landscape Issues 11 (1) 1994:24–9; and (with C.O.Hunt and D.S.Crook) ‘Traditional irrigation strategies and their implications for sustainable livelihoods in semi-arid areas: examples from Switzerland and the Maltese islands’, in H.Wheater and C. Kirby (eds) Hydrology in a Changing Environment, Volume II: 485–94, Chichester, John Wiley and Sons 1998. (Institutional address: Division of Geographical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK) JOHN KINAHAN (PhD 1989, Witwatersrand) is an independent consultant in archaeological and palaeoenvironmental studies, and has authored more than forty scientific papers in diverse fields. Recent publications include: Pastoral Nomads of the Central Namib Desert: The People History Forgot, Windhoek, New Namibia Books 1991; ‘The rise and fall of nomadic pastoralism in the central Namib desert’, in T.Shaw, P.Sinclair, B.Andah and A.Okpoko (eds) The Archaeology of Africa: Food, Metals and Towns: 372–85, Routledge, One World Archaeology 20 1993; and ‘A new archaeological perspective on nomadic pastoralist expansion in south-western Africa’, in J.E.G.Sutton (ed.) The Growth of Farming Communities in Africa from the Equator Southwards: 211–26, Nairobi, British Institute in Eastern Africa 1996. He is currently attached to the University of Uppsala in Sweden while carrying out research on the long-term environmental impacts of nomadic pastoralism in Namibia and Tanzania. (Institutional address: Quaternary Research Services, PO Box 22407, Windhoek, Namibia, and Department of Archaeology and Ancient History, St Erikstorg 5, University of Uppsala, Uppsala S75310, Sweden) SANDER VAN DER LEEUW, presently Professor in the History and Archaeology of Techniques at the Sorbonne in Paris, followed a university education in History and Archaeology at the University of Amsterdam (PhD 1976), and has taught at the Universities of Leiden and Amsterdam in the Netherlands, Reading and Cambridge in the UK, Michigan (Ann Arbor), Massachussetts (Amherst) and the Santa Fe Institute in the USA, and the Australian National University. He has undertaken fieldwork in Syria, Holland, the Philippines and France. His main research interests embrace the technology of ancient pottery making, regional and spatial archaeology, the relations between people and their environment through time as well as in the present, and the use of dynamical systems modelling for understanding social systems. Among his publications are: Studies in the Technology of Ancient Pottery, Amsterdam, University of Amsterdam, Institute for Pre- and Protohistory 1976; (with A.C.Pritchard) The Many Dimensions of Pottery, Amsterdam, University of Amsterdam, Institute for Preand Protohistory 1982; (with R.Torrence) What’s New? A Closer Look at the Process of Innovation, London, Unwin Hyman, One World Archaeology 14 1987; (with J.McGlade) Time, Process and Structured Transformation in Archaeology, London, Routledge 1997; and The ARCHAEOMEDES Project: Understanding the Natural and Anthropogenic Causes of Land Degradation and Desertification in the Mediterranean, Luxemburg, Publications Office of the European Union 1998. (Institutional address: Boit 05, Maison de l’Archéologie et de l’Etnologie, 21 Alice de l’Université, 92023 Nanterre, France)

DAVID MATTINGLY is Professor of Roman Archaeology in the School of Archaeological Studies at the University of Leicester and has conducted fieldwork in North Africa, the Near East, the Mediterranean and Britain. He took his BA and PhD at the University of Manchester, the latter a study of Roman Libya. Following the tenure of a British Academy Post-Doctoral Fellowship at the University of Oxford researching Roman-period olive oil production, he taught at the University of Michigan (Ann Arbor), before joining Leicester in 1992. He has published extensively on landscape archaeology, especially of arid zones, the Roman empire and its impact on people and environment, and olive oil production and trade in the ancient world. In addition to his current field project in Fezzan (Libya), which he discusses in his chapter (Chapter 9), he is also collaborating with Graeme Barker and David Gilbertson in the Wadi Faynan Landscape Survey, Jordan (Chapter 4). His principal publications include: (with J.A.Lloyd) Libya: Research in Archaeology, Environment, History, and Society 1969–1989, London, Society for Libyan Studies 1989; (with G.D.B.Jones) An Atlas of Roman Britain, Oxford, Blackwell 1993; Tripolitania, London, Batsford 1995; (with G.Barker, D.Gilbertson and B.Jones) Farming the Desert: The UNESCO Libyan Valleys Archaeological Survey. Volume One: Synthesis, Volume Two: Gazetteer and Pottery, Paris, UNESCO 1996; Dialogues in Roman Imperialism. Power, Discourse and Discrepant Experience in the Roman Empire, Portsmouth, RI. 1997; and (with M.Gillings and J.van Dalen) Mediterranean Landscape Archaeology 3: Geographical Information Systems and Landscape Archaeology, Oxford, Oxbow 2000. (Institutional address: School of Archaeological Studies, University of Leicester, Leicester LE1 7RH, UK) PAUL E.MINNIS is an Associate Professor at the University of Oklahoma. His research interests include paleoethnobotany, human ecology, social evolution, human responses to food shortages, the relationships between archaeology and biodiversity, and the prehistory of the North American Southwest. For the past decade he has co-directed an archaeological project in northwestern Chihuahua, Mexico, to understand the regional setting of Casas Grandes, one of the most complex prehistoric polities in North America. His books include: Social Adaptation to Food Stress, Chicago, University of Chicago Press 1985; (with C.Redman) Perspectives on Southwestern Prehistory, Boulder CO, Westview Press 1990; (with W.Elisens) Biodiversity and Native America, Norman, University of Oklahoma Press, 2000; and Ethnobotany: A Reader, Norman, University of Oklahoma Press 2000. (Institutional address: Department of Anthropology, University of Oklahoma, Norman, OK 73019 USA) MARK NESBITT is an ethnobotanist at the Centre for Economic Botany, Royal Botanic Gardens, Kew. An undergraduate degree in agricultural botany at Reading University was followed by postgraduate training in archaeobotany at the Institute of Archaeology, University College London. Since 1985 he has been involved in a wide range of archaeological fieldwork in the Near and Middle East, including Turkey, Iraq, Bahrain and Turkmenistan. His research interests include the origins, development and sustainability of crop husbandry in arid lands, the evolution of Old World cereals, and archaeological and ethnographic evidence for wild plant foods in the temperate zones. Publications include: ‘Archaeobotanical evidence for early Dilmun diet at Saar, Bahrain’, Arabian Archaeology and Epigraphy 4, 1993:20–47; ‘Plants and people in

ancient Anatolia’, Biblical Archaeologist 58, 1995:68–81; (with D.Samuel) ‘From staple crop to extinction? The archaeology and history of the hulled wheats’, in S.Padulosi, K.Hammer and J.Heller (eds) Hulled Wheats: 41–100, Rome: IPGRI 1997. (Institutional address: Centre for Economic Botany, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, UK) PAUL NEWSON is a PhD student at the University of Leicester. After a first career as a graphic designer he took his BA and MA in archaeology at University College London. Funded by the Natural Environment Research Council, he is preparing his PhD thesis at Leicester on water management strategies in Roman Arabia and their implications for understanding processes of Romanization, combining field studies of dryland water-management systems of the kind discussed in his chapter (Chapter 5) with a detailed analysis of Roman-period field systems in the Wadi Faynan in southern Jordan using Geographical Information Systems. In 1999 he was Acting Assistant Director of the Council for British Research in the Levant’s British Institute at Amman for Archaeology and History. (Institutional address: School of Archaeological Studies, University of Leicester, Leicester LE1 7RH, UK) SARAH O’HARA is a Reader in Environment and Society in the School of Geography, University of Nottingham. She completed a BSc in Physical Geography and Geology at the University of Liverpool, an MSc in Geography at the University of Alberta, Canada, and a DPhil. in Geography at the University of Oxford. Her research interests include environmental reconstruction, human/environmental interactions and water resource management in the world’s drylands. Her research has been carried out in Albania, Canada, Iran, Mexico, Turkmenistan and Uzbekistan. More recently she has begun collaborating with Professor Julian Henderson on the Ancient Raqqa Industrial Project in Syria. Recent publications include: (with D.Thomas, M.D. Bateman and D.Mershahi) ‘Development, age, and environmental significance of a Late Quaternary sand ramp, central Iran’, Quaternary Research 48, 1997:155–61; (with T.Hannan) ‘Irrigation and water management in Turkmenistan: past systems, present problems, and future scenarios’, Europe-Asia Studies 51, 1999:21–41; and ‘Learning from the past: water management in Central Asia’, Water Policy (forthcoming, 2000). (Institutional address: School of Geography, University of Nottingham, Nottingham NG7 2RD, UK) JEFFREY R.PARSONS (PhD in Anthropology, University of Michigan 1966) is currently Professor of Anthropology and Curator of Latin American Archaeology at the University of Michigan, Ann Arbor, Michigan USA. In addition to ongoing fieldwork in the Valley of Mexico since 1961, he has also worked in Guatemala (Tikal, Peten, 1966), Peru (Chilca, central coast, 1969–1970 and Junin, central highlands, 1975–76), Iceland (Eyaforur, 1985) and northwest Argentina (Jujuy, 1995). His research interests include the development of pre-industrial complex society, settlement pattern studies, archaeological ethnography and (in the Andes) long-term relationships between herders and agriculturalists. Current plans include fieldwork on the pre-hispanic utilization of lacustrine resources in the Valley of Mexico, and prehispanic regional organization in the Peruvian central highlands. Significant publications include: (with C.M.Hastings and Ramiro Matos M.) ‘Rebuilding the state in highland Peru: herder-cultivator interaction during the Late Intermediate Period in

the Tarama-Chinchaycocha region’, Latin American Antiquity 8, 1997:317–41; (with G.Mastache, R.Santley, and M.C. Serra) Arqueología Mesoamericana: Homenaje a William T.Sanders, Mexico D.F., Institute Nacional de Antropología e História 1996; ‘Political implications of pre-hispanic chinampa agriculture in the Valley of Mexico’, in H.Harvey (ed.) Land and Politics in the Valley of Mexico: A Two Thousand-Year Perspective: 17–42, Albuquerque, University of New Mexico Press 1991; and (with M.H. Parsons) Maguey Utilization in Highland Central Mexico: An Archaeological Ethnography, Ann Arbor, University of Michigan Museum of Anthropology, Anthropological Paper No. 82, 1990. (Institutional address: Department of Anthropology, University of Michigan, Ann Arbor, Michigan MI 48104, USA) STEVE A.ROSEN teaches archaeology in the Department of Bible and Ancient Near East at Ben-Gurion University in Beer-Sheva, Israel. He received his Bachelor’s degree from the University of California at Berkeley in mathematics and anthropology and his graduate degrees in anthropology from the University of Chicago. Prior to his current position, he worked for eight years as a survey archaeologist for the Archaeology Survey of Israel in the Negev. His research interests include desert adaptations, the archaeology of pastoral nomadism, Levantine prehistory and lithic analysis. His major publications include: Lithics After the Stone Age, Walnut Creek, Altamira Press 1997; (with G.Avni) The ‘Oded Sites: Investigations of Two Early Islamic Pastoral Camps South of the Ramon Crater, Beer-Sheva, Ben-Gurion University Press 1997; and Archaeological Survey of Israel Map of Be’erot Oded, Beer-Sheva, Ben-Gurion University Press 1994. (Institutional address: Archaeology Division, Ben-Gurion University, PO Box 3653, Beer-Sheva, 84105 Israel) ROBERT SOPER (MA Cambridge, UK) is a Senior Research Fellow in Archaeology at the University of Zimbabwe. Between 1962 and 1985 he worked for the Nigerian Antiquities Department, the British Institute in Eastern Africa, Ibadan University, and the University of Nairobi. His principal research interests have included the later prehistory of East Africa (especially the Early Iron Age and later ceramics), the site of Oyo Ile in Nigeria, and Great Zimbabwe tradition sites in northern Zimbabwe. Significant publications include: ‘A general review of the Early Iron Age in the southern half of Africa’, Azania 6, 1972:5–37; ‘Roulette decoration on African pottery’, African Archaeological Review 3, 1985:29–51; ‘The palace at Oyo Ile, western Nigeria’, West African Journal of Archaeology 22, 1993; and (with B.E.Kipkorir and J.W.Ssennyonga) The Kerio Valley: Past, Present and Future, Nairobi, University of Nairobi Institute of African Studies 1983. He has conducted research on the Nyanga terrace complex since 1993, and a monograph on this is forthcoming. (Institutional address: History Department, University of Zimbabwe, PO Box MP 167, Mount Pleasant, Harare, Zimbabwe) GREG SPELLMAN is a lecturer in the School of Environmental Science at University College Northampton (UK). After a BA in Geography at the University of Sheffield, he took a PGDip in Applied Meteorology and Climatology at the University of Birmingham and an MA in Professional Education at the University of Leicester. His research interests include synoptic climatology, extreme hydrological events in the Iberian peninsula and the meteorology of air pollution. He is currently researching on the synoptic climatology of Spain, particularly the evaluation of various downscaling

methods in order to improve regional climate change scenarios. Recent publications include: ‘An application of artificial neural networks to the prediction of surface ozone concentrations in the United Kingdom’, Applied Geography 19, 1999:123–36; and ‘Investigating the synoptic climatology of precipitation in Mallorca, Spain’, Journal of Meteorology 23, 1998:117–30. (Institutional address: School of Environmental Science, University College Northampton, Northampton NN2 7AL, UK) JOHN E.G.SUTTON (MA Oxford, PhD East Africa, FSA) was Director of the British Institute in Eastern Africa from 1983 to 1998 and was previously Professor of Archaeology at the University of Ghana. He has been mainly concerned with later archaeology and its contribution to African history, with a special interest in field systems and agricultural technology. His first visit to Engaruka in the northern Tanzanian Rift Valley—the subject of his contribution to this volume—was in 1963, while a research scholar of the British Institute. Later, as a lecturer at the University of Dar es Salaam, he continued the investigation of the Engaruka irrigation-agricultural settlement with student assistants. That study has been extended in more recent years within a broader comparative project on African field systems and cultivation strategies. Engaruka and other prominent sites are described in detail in Archaeological Sites of East Africa: Four Studies (special volume 33 of Azania for 1998), and there is a shorter illustrated account in A Thousand Years of East Africa (Nairobi, British Institute of East Africa 1990). Another special volume of Azania (29/30, 1995), The Growth of Farming Communities in Africa from the Equator Southwards, surveyed the present state of research on the Early Iron Age and the Bantu agricultural expansion. (Address: 118 Southmoor Road, Oxford OX2 6RB, UK) MATS WIDGREN teaches at Stockholm University, where he is a Professor in Human Geography. He received his PhD in Stockholm in 1983 and has researched on the historical geography of agricultural landscapes from the Iron Age to the present in Sweden and in southern and eastern Africa. Among his publications are: ‘Is landscape history possible?’, in P.Ucko and R.Layton (eds) The Archaeology and Anthropology of Landscape: 94–103, London, Routledge 1999; ‘Fields and field systems in Scandinavia during the Middle Ages’, in G.Astill and J.Langdon (eds) Medieval Farming and Technology—The Impact of Agricultural Change in Northwest Europe: 173–92, Leiden, Brill 1997; ‘Strip fields in an iron age context: a case study from Västergötland, Sweden’, Landscape History 12, 1990:5–24; and Settlement and Farming Systems in the Early Iron Age: A Study of Fossil Agrarian Landscapes in Östergötland, Sweden, Stockholm, Almquist & Wiksell 1983. His most important works in Swedish are his contribution to the first volume of the agrarian history of Sweden Jordbrukets första femtusen år (1998) and a book on medieval field systems in Bohuslän, Sweden (1995). (Institutional address: Department of Human Geography, Stockholm University, S-106 91 Stockholm, Sweden)

Foreword One World Archaeology is dedicated to exploring new themes, theories and applications in archaeology from around the world. The series of edited volumes began with contributions that were either part of the inaugural meeting of the World Archaeological Congress in Southampton, UK in 1986 or were commissioned specifically immediately following the meeting—frequently from participants who were inspired to make their own contributions. Since then the World Archaeological Congress has held three further major international congresses: Barquisimeto, Venezuela (1990), New Delhi, India (1994), and Cape Town, South Africa (1999). It has also held a series of more specialised ‘intercongresses’ focusing on: Archaeological ethics and the treatment of the dead (Vermillion, USA, 1989), Urban origins in Africa (Mombasa, Kenya, 1993), and The destruction and restoration of cultural heritage (Brac, Croatia, 1998). In each case these meetings have attracted a wealth of original and often inspiring work from many countries. The result has been a set of richly varied volumes that are at the cutting edge of (frequently multi-disciplinary) new work, and which provide a breadth of perspective that charts the many and varied directions that contemporary archaeology is taking. As series editors we should like to thank all editors and contributors for their hard work in producing these books. We should also like to express our thanks to Peter Ucko, the inspiration behind both the World Archaeological Congress and the One World Archaeology series. Without him none of this would have happened. Martin Hall, Cape Town, South Africa Peter Stone, Newcastle, UK Julian Thomas, Manchester, UK June 2000

Preface This book stems from a symposium organized by the editors on the archaeology of drylands held at the World Archaeological Congress at Cape Town in January 1999. The Congress provided the opportunity to bring together scholars working on the archaeology of different regions of the world’s drylands, to pool experiences and in particular to investigate the extent to which we could discern common themes. Although over a third of the world’s population today lives in arid and semi-arid lands, there are many gaps in our understanding about how fragile or resilient these regions are for human settlement. To fill these gaps we need to answer questions that are likely to be of very great significance for the global community in the twenty-first century. Many dryland regions have abundant remains of ancient settlement, and people have often speculated that the actions of farmers and herders in the past must have been important in creating the degraded landscapes of the present. For decades the debate has been characterized more by speculation than informed debate and by a propensity to argue for simple processes of cause and effect in terms of climatic change or humanly induced environmental degradation. In the past fifteen years or so, however, inter-disciplinary archaeological and palaeoecological studies (especially when employed within integrated research frameworks) have demonstrated their potential to move the debate forwards by providing detailed case studies of how ancient societies actually exploited dryland landscapes, how they interacted with them, and the complex environmental and social contexts in which they variously succeeded or failed. Moreover, as we conclude in Chapter 1, the advancement of understanding about past dryland societies and environments, and of the complexity of their interactions with each other, has a particular urgency, given the way in which changing political agendas have been prone to either demonize or sentimentalize them. Nine papers were given at the Cape Town symposium, and a series of common themes about dryland settlement emerged from the discussion. Other papers were then commissioned by the editors, so that the collection as a whole would draw on the archaeology of different kinds of drylands throughout the world (the locations of which are shown in Figure 1.3), different periods of the past and different kinds of societies, but all addressing the issues we had identified at Cape Town to give a comparative perspective. Common themes, though, as we discuss in Chapter 1, do not equate with similar solutions to dryland living, or similar responses to threats and opportunities: the archaeology of drylands is eloquent testimony perhaps most of all to people’s ingenuity, as well as to their resilience. The editors would like to express their thanks to the organizers of the 1999 World Archaeological Congress for their invitation to organize the Drylands Archaeology symposium, and for every assistance from them during the conference. We would also like to thank the Society for Libyan Studies for a generous grant towards our two fares to Cape Town, augmented in the case of GB by a grant from the Staff Development Fund of

the Faculty of Arts of the University of Leicester. We are very grateful to all the contributors to the volume for their patience, especially those who contributed to the symposium, whose debates helped frame the discussion document we then circulated to them and to the authors of the papers commissioned afterwards, and who have remained committed to our idea of the integrated comparative volume, despite the timelag since the conference. Finally, we would like to dedicate this book to the memory of Barri Jones. Barri was Professor of Archaeology at the University of Manchester and introduced us both to dryland archaeology in the UNESCO Libyan Valleys Survey. He died on the eve of his retirement in the summer of 1999, leaving a legacy of a major scholarly output of books and papers, an army of professional and amateur archaeologists enthused with his passion for the subject and, for his desert companions in particular, memories of hairraising adventures in his company. He was a frenetic personality who was both enchanting and exasperating to work with—he was notorious for doing too many things at once, mostly while nominally in control of a Landrover! Amongst his many talents, though, he had an extraordinary topographical eye: he was liable to get us lost in some desert waste to visit an archaeological site once noted by a traveller 100 years ago, and thrash the vehicle in the process, but he was also by far the best person to be with to get safely back to camp again. Graeme Barker and David Gilbertson January 2000

Part I INTRODUCTION

1 Living at the margin: themes in the archaeology of drylands GRAEME BARKER AND DAVID GILBERTSON

INTRODUCTION Drylands cover 40 per cent of the land area of the Earth: their total area is about 60 million km2, of which about ten million km2 are hyper-arid deserts (Fig. 1.1). Drylands support over one fifth of the world’s population, and arid and semi-arid lands together over a third. Living conditions vary from the most affluent and profligate to the desperately poor—in some cases in close proximity. The political stability and ecological, economic and social sustainability of dryland settlement are among the most daunting challenges confronting the global community in the twenty-first century: water seems likely to be a primary flashpoint for disputes between neighbouring states, with dryland irrigation systems under strain from fast-growing populations;

Figure 1.1 The world map of drylands Source: After UNEP, 1992 and with environmental refugees from global warming predicted to be in the order of 150 million by the year 2050 under the business-as-usual scenario (Houghton, 1997), the catastrophic consequences will be particularly acute for dryland populations. Many dryland regions have archaeological remains suggesting that once upon a time

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there must have been intensive phases of settlement in what are now dry and degraded environments (Fig. 1.2). People have often speculated about what must have happened to turn past glories into present-day barrenness, generally dividing in favour of climatic change or human agency as the primary culprit. Perhaps the climate shifted to greater aridity? Or was it that people sowed the seeds of their own destruction through their folly, for example by developing irrigation systems that caused salinization, or by stripping the landscape for fuelwood, or by allowing their livestock to over-graze the vegetation? In general, the debate has been characterized more by confident assertion than well-founded argument. Furthermore, as we discuss later in this chapter, contemporary ecological theory suggests that relations between dryland environments, climate and people are by no means simple (Beaumont, 1993): drylands can sometimes be remarkably resilient, for example, recovering relatively quickly from over-exploitation, and simple procedures by farmers can often protect against the latter (Mortimore, 1998; Tiffen et al., 1994). These findings are at odds with the simplistic models that have tended to dominate the archaeological literature about how climate and people may or may not have affected drylands in the past.

Figure 1.2 A Roman-period fortified farm on the desert margins of Tripolitania, northwest Libya Photograph: G.Barker Modern inter-disciplinary archaeology, especially when working in conjunction with other social and environment sciences, has the potential to move the debate forward. Archaeology deals with the entire human past, its geographical scope is regionally specific but worldwide, its scale of enquiry ranges from distributions and processes of change at the global scale and over millennia down to the actions of individuals. We can use the techniques of landscape archaeology to understand how different kinds of societies, whether recent or remote in time, exploited the different dryland environments

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of the world. We can characterize the risks and opportunities confronting those societies, identify the solutions they reached and often the reasons for them, as well as monitoring the short- and long-term effects of those solutions. By developing a more sophisticated understanding than has hitherto characterized the debate about variability in past land use strategies and the reasons for their successes and failures, archaeology can contribute effectively to modern debates about desertification and the sustainability of dryland settlement (Beaumont, 1993). The World Archaeological Congress held at Cape Town in January 1999 provided an ideal opportunity to explore these issues from the perspectives of various scholars working on the archaeology of different regions of the world’s drylands. The symposium focused on nine contributions, discussing work in the Near East, North and sub-Saharan Africa and North America, all of which are represented in this volume. A series of common themes about

Figure 1.3 The location of the case studies in this volume; numbers refer to chapter numbers dryland settlement rapidly emerged, and the papers presented at the symposium were rewritten, and further papers commissioned, to address these common issues within a comparative perspective in this book, with case studies drawn from different kinds of dryland regions throughout the world (Fig. 1.3). Common themes, though, as we discuss below, do not equate with similar solutions to dryland living, or similar responses to risks and opportunities.

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THEMES IN DRYLAND ARCHAEOLOGY The term ‘drylands’ obviously fixes attention upon low precipitation. Common knowledge emphasizes that the climatic significance of this shortage depends upon the other aspects of the atmospheric environment—the radiation budget, thermal regime, wind regime, the sources and pathways of moisture, including fog, as well as the many other components of the biosphere and lithosphere that play significant parts in the hydrological cycle. The meteorology and climatology that produce drylands are not simple (Spellman, Chapter 2): understanding them requires an appreciation of variability of precipitation and drought in both space and time. Rainfall in many drylands is typically characterized as consisting of erratic, short, localized downpours of high intensity. Low average precipitation totals are associated with notable variability. Fierce and localized downpours creating sudden and dangerous floods are the primary resource base that many indigenous peoples have had to utilize to maintain themselves, their crops and their animals for millennia (as well as environmental hazards for archaeologists working in arid lands; see Fig. 1.4!). However, it is the prospect of prolonged and severe drought that dominates thinking about drylands. Instrumental, historical and palaeoenvironmental records show that episodes of severe drought lasting decades or more in length have not been uncommon in many drylands over the last few thousand years (e.g. Bureau of Meteorology, n.d; Fritts, 1991; Lamb et al., 1995; Nicholson, 1994). Ingenuity, flexibility and enterprise have been required from individuals, communities and organizations to negotiate their survival in the face of such uncertainty and risk. It is important to remember that, apart from such fluctuations at the scale of seasons and decades, modern drylands have also been part of tremendous fluctuations in climate operating at the global scale in the remote past, from major shifts in the world’s oceanographic and atmospheric systems. The period from approximately 18,000 to 10,000 years ago, the last phase of the Pleistocene (the ‘Ice Age’), saw the last major ice advances of glaciers and icesheets in the high latitudes. Regions of the world that now enjoy a temperate climate, such as Europe and North America, were cold and arid. Regions such as the Sahara were hyper-arid: long-term reductions of rainfall reached well beyond the present desert margin, as far south as present-day Nigeria, with much of interior North Africa having to be abandoned by human populations. However, between 10,000 and 8,000 years ago, during

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Figure 1.4 Drowning in drylands?—two vehicles of the UNESCO Libyan Valleys Survey sunk in a flash-flood Photograph: G.Barker the opening millennia of the Holocene or Postglacial, the environment across the Sahara was notably wetter than occurs today, with the development of lakes and woodland in favoured locations such as those that are now desert oases and savannah-like habitats on the surrounding plateaux (Barker et al., 1996; and see Mattingly, Chapter 9). The people who colonized these places were able to live by plant and shellfish gathering, fishing and hunting not just steppe animals like gazelle but wetland species such as turtle, hippo and crocodile (Cremaschi and di Lernia, 1998; Wendorf and Schild, 1980). In the Near East, wetter environments at this time were the context for the development of mixed farming systems of the kind found in the Wadi Faynan in southern Jordan (Barker, Chapter 4), and the first farming in Turkmenistan may also have developed in wetter conditions than today (Nesbitt and O’Hara, Chapter 6). Desiccation started to develop about 6,000 years ago in North Africa and the Near East, with people responding differently. In the Sahara, people shifted to cattle and sheep/goat herding (Barich, 1987, 1998; Wendorf et al., 1984, 1989), whereas the farmers of Wadi Faynan started to experiment with methods of trapping and storing water, which were the beginnings of recognizable systems of dryland farming there (Chapter 4). It was also about this time, in the fourth millennium BC, that prehistoric farmers in Turkmenistan started to build canals to divert floodwaters and, via small feeder channels (aryks), bring it to their fields (Chapter 6). So far as we can tell, it was not until notable aridification developed in the Sahara around 4,500 years ago, as seasonal streams replaced perennial streams, salt pans replaced fertile lake floors, and the modern regime of flash-floods and droughts developed, that similar systems of dry farming were developed by farmers living in the oases (Chapter 9) and on the desert margins such as the Tripolitanian Pre-desert (Barker et al., 1996). Archaeological evidence for the development of irrigation-based farming is a recurrent theme throughout this book because, whilst far from all drylands are warm or hot for all

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or part of the year, the provision of an adequate and reliable supply of water in warm and sunny regions has been a goal for innumerable communities over time. Rainwater harvesting and floodwater farming are described for North America, Africa and Asia in a variety of chapters. Four major themes emerge from these case studies, the first three of which are closely inter-related. The first is the resilience of many farmers in antiquity to cope with harsh and riskprone arid environments and their climatic vicissitudes over long periods of time. This longevity of occupation points to an inherent robustness of many of these past communities, their attitudes and ways of life. The second is the repeated evidence for the similarity of the ‘building blocks’ or ‘tactics’ employed by most ancient farmers in drylands—building walls to trap soil and divert or stem water flow, building channels (including underground in the case of the Turkmenistan qanats [Chapter 6] and Libyan foggaras [Chapter 9]) to divert water, and so on. The third is the remarkable variability in the overall systems that were put together from such building blocks and the way they invariably reflect detailed local knowledge of topography, weather patterns, and so on: ancient farmers knew from observation exactly how and where the water would flow after a storm, and so knew how best to manage that flow to suit their purposes. The fourth critical finding from our survey, though, is that the diversity we can observe in the archaeology of dryland farming systems is in no sense just a straightforward matter of commonsense observation by ancient farmers of what was the ‘best fit’ to particular environmental or economic circumstances. We can see today how dryland communities attempt to manage themselves and their habitats within the context of a whole nexus of attitudes, beliefs, as well as economic, social, geographical, educational, agricultural and technological processes; and whilst many of these details will elude archaeologists, given the nature of our evidence, the case studies illustrate how people took choices, and not always the right ones, within a complex mix of factors, including perceptions of risk, the need or desire for economic advantage, and the institutional and regional context in which they were operating. As Widgren comments (Chapter 14), models of agrarian development too often assume even developments of farming systems in response to particular environmental, social or economic pressures, but the archaeological record emphasizes above all the unevenness of development in both space and time. We do not see the kind of evolutionary development of land use systems so often assumed for the past, for example from simple to complex or from extensive to intensive—they were ‘formed and changed within specific, place-bound, social, historical, and ecological contexts’ (Widgren, p. 262). One key influence on the character and scale of an irrigation system was, not surprisingly, related to the extent to which the agricultural product was to serve only the local community. Examples of such systems, ‘islands’ of relatively intense landscape development, are described for societies varying widely in time, place and social complexity, for example in the North American Southwest in prehistoric times (Minnis, Chapter 15), the Achaemenid or Parthian periods in Turkmenistan (Chapter 6), the Libyan oases (Mattingly, Chapter 9) and the Tricastin region of southern France (van der Leeuw, Chapter 18) in the Roman empire, and at various localities in sub-Saharan Africa in recent centuries (Sutton, Chapter 11; Soper, Chapter 12; Widgren, Chapter 14). Widgren illustrates how both hierarchies and the absence of hierarchies can be associated

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with labour-intensive agriculture and how both market orientation and subsistence farming can be connected with labour-intensive farming. These landscapes and irrigation systems stand in contrast not only to the examples described in Israel (Rosen, Chapter 3), Jordan (Barker, Chapter 4), Syria (Newson, Chapter 5) and northwest Libya (Gilbertson et al., Chapter 8) of archaeological landscapes that were once very productive, if peripheral, parts of the imperial economies, characterized by the large-scale import and export of goods, products and information to the core areas of the Mediterranean, but also to the somewhat similar relationship of highland Mexico to the rest of the Inca state (Parsons and Darling, Chapter 16). ‘Patchiness’ in distribution has also been identified in the studies by Jones and Crook (Chapter 17) of the Swiss bisses—canal systems that have tapped and redistributed water within the surprisingly dry environment of the Canton of Valais for over a millennium but that remain a relatively unknown but vital component of the economy of one the world’s richest and technologically sophisticated countries. Clearly, archaeological investigation of ‘marginal’ landscapes has to engage with the need for complex inter- and intra-regional articulations of explanations of cause and effect. All archaeologists also have to recognize the commonplace dictum that ‘the past is a foreign country’: things were thought and done differently there. Then, as now, it seems that many individuals, organizations and polities have behaved in relation to their situation and their environment in manners that do not appear rational to the modern external observer or to those with the wisdom of hindsight. Then, as now, people made poor decisions, foolish decisions, self-interested decisions, carried out actions that they or their neighbours had cause to regret; or, more generally, they misunderstood their land and situation. One striking example of long-term devastation caused by the economic needs of the Roman empire was the pollution of the Wadi Faynan in Jordan by copper and lead mining (Barker, Chapter 4), but it is important that we do not dismiss such actions as the exclusive domain of market-driven economies (like the profligacy of Turkmenistan irrigation farmers once they lost their sense of ownership of the system in the Soviet period: Chapter 6): as Minnis (Chapter 15) comments in the case of North America, indigenous subsistence foragers and farmers, equally, have not always been environmentally ‘correct’, ‘sound’ or ‘neutral’. A good example of the importance of perception affecting decision making by dryland farmers responding to adverse conditions occurred during the great drought that affected the wheat-arid far north frontier of South Australia between 1881 and 1884, the climatic effects of which were documented in remarkable detail by a sophisticated network of instrumental records maintained by, amongst others, telegraph operators (Bureau of Meteorology, n.d.). The well-known account of this episode by Meinig (1962) based upon parliamentary records and newspapers reveals that the human and economic impacts of the first two years’ drought were devastating. Many wheat farmers were sustained by their belief that the ‘rain followed the plough’: more ploughing and tilling, they thought, would release further soil moisture into the atmosphere, and so break the drought. Others farmers, desperate to maintain overall production totals and to pay their mortgages to the Government for their newly acquired lands (pastureland hitherto), ploughed and planted ever larger areas of bush, believing that minimal returns from vast areas would compensate for the poor yields per acre. Both strategies, of course, made

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things far worse—as the drought grew worse and human distress grew ever more profound, ever larger areas of land were being ploughed and farmed. It is salutary for archaeologists, who rarely have access to such sophisticated documents or precise chronologies, to reflect on the complete reversal in present thinking of the nature of human—environment interactions that underpinned these farmers’ behaviour just over a century ago. The case studies demonstrate repeatedly that drought, however pernicious and sustained, is not necessarily the sole cause of ‘abandonment phases’ identified in the archaeological record of drylands. Chapter 10 by Butler and D’Andrea, for example, shows that episodes of famine and distress (like, indeed, those of success and prosperity) cannot be explained in drylands by consideration of one factor, even such vital factors as drought or flood. Discussing the Northern Highlands of Ethiopia, a region almost synonymous with drought and famine for most readers, they emphasize the potency for understanding famine in the area of the following, sometimes archaeologically invisible, factors: human smallpox; cattle rinderpest; plagues of predators such as locusts, ants and army worms; conflict; and social and political circumstances. In fact, drought alone seldom causes famine. The sustainability of many dryland communities, pastoral (Kinahan, Chapter 13) as well as agricultural, is underpinned especially by the flexibility of traditional practices: their capacity to avoid, to mitigate and to create buffers against risk and adversity; more generally their ability to organize themselves effectively in drought-prone habitats; and, in the last resort, their willingness to relocate (Mortimore, 1998:122). We can see from the archaeological record that systems without such flexibility did not have the necessary resilience for longterm survival, as in the case of the productive but short-lived systems of cash-crop farming that Romanized Libyans developed in the Tripolitanian Pre-desert to supply the local military and coastal urban markets (Gilbertson et al., Chapter 8), or the intensively irrigated fields built to feed the large industrial workforce of Roman miners in the Wadi Faynan in Jordan (Barker, Chapter 4), or the massive centralist-administered irrigation systems of Soviet Turkmenistan (Nesbitt and O’Hara, Chapter 6).

ARCHAEOLOGY AND DESERTIFICATION During the last few decades, many of the world’s drylands—the hotter drylands especially but not exclusively—have been viewed as threatened by ‘desertification’. The term was coined by Aubreville (1949) in a report on the vegetation of Africa, and its meaning has developed through time. Thomas and Middleton (1994:9–10) defined it as ‘land degradation in arid, semiarid, and dry sub-humid areas resulting mainly from adverse human impact’, and though some authors have also used the term to refer to land degradation caused by a sustained aridification of climate, most prefer to use the term to refer to the effects of human actions, though climate and people can clearly work in tandem to produce deterioration in dryland environments, as may be the case in the context of global warming today (Barrow, 1995; Millington and Pye, 1994; Spellman, Chapter 2). The key ideas focus upon significant and long-term degradation producing a loss of potential in biological, soil and water resources. Manifestations of humanly

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caused degradation may include decreased vegetation cover, timber loss, salinization, reduced water supplies, lower crop yields, outbreaks of disease, accelerated erosion of soils and dust storms, and induced regional climatic change, all encapsulated in the popular metaphor of the conversion of pastoral or arable lands within drylands into desolate and sterile desert. The Green agendas of recent decades have rightly and repeatedly focused on dryland ecosystems and the sometimes appalling consequences of human impacts upon them (Fantechi and Margaris, 1986), often induced or certainly exacerbated by top-down programmes of economic development (IFAD, 1992). Beaumont (1993:474) concluded his book with a bleak prediction of the inevitability of this process for the world’s poorest nations: ‘in certain cases land degradation may be a sacrifice which has to be paid in order that local populations can survive future drought or famine’. According to Tolba and el-Kholy (1992:134), the current rate of desertification is about 60,000 km2 per year, amounting to 0.11 per cent per year of the total area of dryland. On this calculation, desertification today threatens no less than 70 per cent of the world’s drylands, which represents over 25 per cent of the world’s land surface. Grainger (1990) and Spooner (1989) argued that such desertification can be recognized in Australia, North America and South Africa in the first half of the twentieth century, and that it was likely to have been a factor in antiquity, too. There are, however, conflicting views about the extent of desertification today. Thomas and Middleton (1994), for example, questioned whether desertification in recent decades is actually a global problem of such vast dimensions, as opposed to local manifestations of local problems of smaller significance. There are also examples of spirals of land degradation being reversed by indigenous technological adaptations working in combination with population growth and market opportunities. The Machakos district of Kenya was considered an environmental disaster in the 1930s because of massive soil erosion and famine, but by 1990 terrace construction had protected arable land, farmed and protected trees provided sufficient fuel-wood, and agricultural production per person and per hectare had increased, sustaining a population five times larger than that of the 1930s (Tiffen et al., 1994). Deforestation and massive erosion on the Yatenga plateau in Burkino Faso were exacerbated by mechanization programmes funded by ill-judged development aid, but the reinstatement of traditional systems of terrace building stopped erosion and doubled crop yields (Lean, 1994). Mortimore (1998:149–56) described an examples of c. 150 years of sustainable intensification by smallholders in Kano, Nigeria, in the context of population growth and monetization. Archaeological remains in many drylands have been grist to the mill of the desertification debate. For example, Hughes with Thirgood (1982:60, 74) wrote that in the more arid regions, forests that formerly moderated the climate and equalized the water supply were stripped away, permitting the desert to advance. The image of ruined cities in North Africa, from which olive oil and timber were exported in ancient times but which were buried beneath desert sand, epitomizes the environmental factor in the decline of civilization…. Roman dams and canals stand in dry wadis today as witness to the fact that the destruction of the vegetation and consequent desiccation have changed the

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environment. Terms such as excessive land use, population pressure, loss of biological diversity and vegetation cover, mis-use of water, accelerated soil erosion and ever-larger human needs all recur in archaeological explanations (Gilbertson et al., Chapter 8), often in association with reference to times of perceived political unrest, military invasion, conflict and drought. In his review of the historical likelihood of humanly induced desertification, Spooner (1989) cautioned against the simplistic tendency to assume that desertification, famine, drought and poverty will inevitably be found together, and several case studies in this book support those who argue for the complexity of desertification processes today. For example, according to Barker et al. (1996) and Gilbertson et al. (Chapter 8, this volume), the vast Romano-Libyan and Islamic settlements and farms of the Libyan Pre-desert at the edge of the northern Sahara seem to have neither produced nor experienced the kind of self-induced environmental degradation described by Hughes with Thirgood (1982). Indeed, the increase in human population numbers, farming intensity and land management probably promoted a greener, more diverse and infinitely richer and productive environment than has occurred since the great aridification in climate that afflicted the region some 4,500 years ago. There are, in fact, good reasons to suspect that Romano-Libyan farmers did have significant and deleterious impacts upon their arid environment, but there are few reasons to believe that catastrophic long-term climatic change, short-term catastrophic drought, or anthropogenically induced environmental degradation played a central role in the progressive abandonment of these settlements—a process that is still underway after nearly 1,500 years. Rosen (Chapter 3) also suggests that substantial cultural changes in the ancient Negev desert are not best explained by climatic catastrophe, invasion or the inabilities of people to manage their desert environment: rather, periods of cultural florescence were related to increased economic and social input from, or integration with, the Mediterranean ‘core area’, with desert pastoralism strongly geared to active markets in the settled zone, and likely to be sorely afflicted by the latter’s collapse. Yet in the adjacent deserts of southern Jordan, the Wadi Faynan Landscape Survey (with many of the same members as the UNESCO Libyan Valleys Survey, and using similar methodologies) has found convincing evidence for dramatic humanly-induced land degradation in the wake of agricultural and industrial intensification in the context of Roman imperialism. In the Saharan Fezzan, Garamantian development of foggara irrigation systems may have been a key factor leading to the decline of their civilization as a result of over-extraction from a non-renewable groundwater source (Mattingly, Chapter 9). Ballais (Chapter 7) argues that increases in soil erosion in the eastern Maghreb in classical antiquity reflected specific combinations of climatic change and human activities, and affected parts of the landscape in different ways. In the Roman imperial centuries, increased intensity of rains, or the annual amount of precipitation, badly affected regions already made vulnerable by vegetation degradation or unwise cultivation systems, whereas the irrigated zones and terraced mountains were more resilient. In the middle and lower Rhône valley in southern France, episodes of climatic change are out of step with archaeologically visible episodes of human impact; in the Tricastin region here, accelerated erosion can be tied clearly with

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the lack of maintenance of Roman drainage systems (van der Leeuw, Chapter 18). The role of pastoralism in desertification, like dryland farming, is much debated. It has often been asserted to be particularly pernicious, the prime cause of a legacy of apparently exhausted, depleted and deserted drylands today. The archaeological literature on drylands is replete with references to the likelihood of ‘over-grazing’, ‘excessive grazing’, and so on, implying that there is today, and that there was in times past, some knowable and realizable intensity of pastoral activity in drylands—a ‘carrying capacity’ which, if exceeded, must have had dire consequences for the pastoralists and their habitats. However, the core of this view—that such a carrying capacity exists—is now being challenged by ecologists who consider that ‘boom-or-bust’ models of animal population numbers may be more appropriate (Thomas and Middleton, 1994). There may never have been sufficient time for any medium- or long-term balance to be struck between livestock numbers and arid environments because arid lands are too variable in their production of forage—this variability itself a consequence of precipitation, which is variable in space and time (Holling, 1973; Noy-Meir, 1978; Olsvig-Whittaker et al., 1993; Scoones, 1995; Walker et al., 1981). Typically, drought is likely to have reduced animal numbers drastically before irreparable damage was done to pastures (Noy-Meir, 1978). Indeed, grazing drylands pastures may have had some overall beneficial impacts (Warren and Khogali, 1992), whilst Olsvig-Whittaker et al. (1993) argue that many dryland pastures may in some sense be ‘adapted’ to grazing stress and that pastoral disturbance could be regarded as a natural component of many arid environments. In brief, not all dryland environments are as fragile as some popular literature suggests (Thomas and Allison, 1993). Parallel arguments about the likely complexity of past relations between pastoralism and ecological change are put forward on the basis of archaeological evidence by Gilbertson (1996) and Kinahan (Chapter 13). In the case of the Maghreb, Ballais (Chapter 7) also concludes that periods of conquest, often assumed in this region to be periods of environmental devastation wrought by nomadic pastoralists, were probably in fact characterized by less arable land, a progressive development of ‘natural’ vegetation and pastures, and so less soil erosion. Holling’s (1973) ecological view that arid lands are ‘non-equilibrium but persistent’ may have utility for many archaeologists working in drylands, not least because it serves as a disincentive to extrapolate from the local diagnosis of an ancient cause and effect to the inference of causality at regional or global scales. The possibility of non-linear relationships within and between environmental processes and human activities must also be considered. Relatively minor changes in the human or biophysical environment can, in principle, set in train self-sustaining sequences of events and processes that can cause the environment to transform from one state to another, with cause and effect entangled. In drylands today, relationships between individuals, communities, institutions and the landscapes with which they interact are clearly neither simple nor linear in form (Ellis, 1995; Phillips, 1993; Chapter 10). The principal argument of the case studies in this volume is that the same was certainly the case in the past, even though the nature of archaeological and palaeoecological evidence is such that it may sometimes be difficult or impossible to identify the key players, critical species or ideas, the nature of underlying trends or pre-disposing factors, the agencies of stability and the triggers of

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change.

CONCLUSION The archaeology of drylands is one of the richest bodies of archaeological data and frequently the most visible for archaeological surveyors, though it is also often amongst the most vulnerable to destruction by development programmes far from the eye of national archaeological services. Moreover, the deflated landscapes of most drylands frequently pose daunting challenges of archaeological analysis, given the paucity of deep stratigraphies and organic remains, though in some cases both the latter are present in rich abundance; palaeoecologists often face similar challenges, requiring similar persistence and ingenuity in response. However, the practical (and often logistical) difficulties of dryland archaeology should not dissuade us from attempting to understand its significance: whilst the details of structure and agency in past dryland settlement will often be problematical to determine, a better understanding of the complexity of people’s interactions with dryland environments must surely underpin the desertification debate. In many parts of the world, too, investigating how past societies lived in drylands is critical for understanding not just how and why they lived as they did, and desertification theory, but also, in the case of ancient water-management systems, the extent to which the latter could or should be rebuilt to the advantage of local communities and their ecosystems today (e.g. Barker et al., 1996). Similar arguments apply to pastoral development programmes (Kinahan, Chapter 13). We need a sophisticated understanding of the environmental and social contexts of ancient dryland farmers and herders, detailed knowledge of modern dryland ecologies, and sympathetic awareness of issues such as the ownership, empowerment and organization of local technologies by indigenous peoples (Cullis and Pacey, 1992; Reij, 1991; and Gilbertson et al. [Chapter 8], Minnis [Chapter 15] and Jones and Crook [Chapter 17]). Finally, as Steve Rosen also points out in Chapter 3 (pp. 57–8), the advancement of understanding of past dryland societies and landscapes through the combination of good archaeological science and social archaeology is critical most of all to combat the politicization of much past theorizing on these matters. Relations between the desert and the sown underpin many origin myths of ethnicity, and the ‘biography’ of arid lands has frequently been rewritten to changing political agendas. The role of desert pastoralists in ancient Palestine as told to us through the Old and New Testaments is an obvious case in point, where it is repeatedly represented as a moral force for good in the history of the Israelites: the preferment of the shepherd Abel over his brother Cain, the farmer; the substitution of the ram for Abraham’s son Isaac; the commandment that lists the ox and the ass before the wife; the parable of the sheep and goats, and the lost sheep; and the role of Christ himself as the lamb of God, the Lord our Shepherd of Psalm 23. A pastoral ideology with numerous parallels to the Biblical stories underpinned the origin myth of the Incas and their sense of their right to rule subject peoples (Brotherston, 1989). Yet in both the Near East and North Africa, simplistic notions of Islamic pastoralist invaders as the prime causes of environmental and cultural decline have stemmed primarily from political agendas (Rosen, Chapter 3; Ballais, Chapter 7), and one of the planks of modern

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Zionism has often been the contrast between the ‘greening of the desert’ of the kibbutz movement (never mind its long-term implications for the River Jordan!) and the depiction of recent bedouin pastoralisrn as inefficient and environmentally destructive. The dryland farming systems of Native American peoples have been variously portrayed as environmentally destructive or in sympathy with the landscape, according to changing colonial and post-colonial perspectives (Minnis, Chapter 15). At the root of the 1990s massacres in Rwanda was the ‘Tutsis’ and Hutus’ belief that they are derived respectively from Nilotic cattle-herders and Bantu farmers—a note left with a group of European tourists killed in Bwindi National Park in Uganda by Hutu guerillas in 1999 read in broken French ‘here is the fate of all the Anglo-Saxons who betray us to the Nilotics against the Bantu cultivators’ (Hannan, 1999)—but in fact there is very little to distinguish the two groups, and the Nilotic/Bantu dichotomy is almost certainly a mistaken creation of nineteenth- and twentieth-century scholarship (Hall, 1987, 1996). As dryland peoples face the uncertainties of the twenty-first century, understanding the richness, diversity and, above all, the complexity of the archaeology of their antecedents has never been more urgent.

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24:81–93. Phillips, J.D. (1993) Biophysical feedbacks and the risks of desertification. Annals of the Association of American Geographers 83(4):630–40. Reij, C. (1991) Indigenous Soil and Water Conservation in Africa . London, International Institute for the Environment and Development, Gatekeeper Series no. SA27. Scoones, I. (1995) (ed.) Living With Uncertainty: New Directions in Pastoral Development in Africa . London, International Institute for the Environment and Development. Spooner, B. (1989) Desertification: the historical significance. In R.Huss-Ashmore and S.H.Katz (eds) African Food Systems in Crisis. Part One: Micro-Perspectives : 111– 62. New York, Gordon and Breach. Sutton, J.E.G. (1977) The African Aqualithic. Antiquity 51:25–34. Thomas, D.S.G. and Allison, R.J. (1993) (eds) Landscape Sensitivity . Chichester, John Wiley and Sons. Thomas, D.S.G. and Middleton, N.J. (1994) Desertification: Exploding the Myth . Chichester, John Wiley and Sons. Tiffen, M., Mortimore, M. and Gichuki, F. (1994) More People, Less Erosion: Environmental Recovery in Kenya . Chichester, John Wiley and Sons. Tolba, M.K. and el-Kholy, O.A. (1992) (eds) The World Environment 1972–1992 . London, Chapman Hall. Walker, B.H., Ludwig, B., Holling, C.S. and Peterman, R.M. (1981) Stability of semiarid savannah grazing systems. Journal of Ecology 69:473–98. Warren, A. and Khogali, M. (1992) Assessment of Desertification and Drought in the Sudano-Sahelian Region 1985–1991 . London, International Institute for Environment and Development. Wendorf, F. and Schild, R. (1980) Prehistory of the Eastern Sahara . New York, Academic Press. Wendorf, F., Schild, R. and Close, A.E. (1984) (eds) Cattle-Keepers of the Eastern Sahara: The Neolithic of Bir Kiseiba . Dallas, Southern Methodist University. Wendorf, F., Schild, R. and Close, A.E. (1989) (eds) The Prehistory of the Wadi Kubbaniya . Dallas, Southern Methodist University, two volumes.

2 The dynamic climatology of drylands GREG SPELLMAN

DEFINING DRYLANDS Surprisingly, given that the critical and unifying variable for dryland environments is a shortage of water on a seasonal or longer-term basis, there has been a long-standing difficulty in determining their geographical extent (Beaumont, 1989; Wallen, 1967), though it is generally estimated that hyper-arid, arid and semi-arid lands in total cover a third of the Earth’s land surface (UNEP, 1992; see Fig. 1.1). The absence of significant moisture is manifest in the characteristics of the soils, vegetation and topography. Consequently, Oliver (1973) and Nir (1974) have suggested ways of identifying arid lands by a variety of non-climatic criteria. Straightforward classical approaches create regionalizations using isopleths of climatic elements with respect to associations with vegetation and agricultural conditions, such as the 250 mm rainfall limit as the arid boundary (Oliver, 1981). In contrast, indexing methods delimit regions with differing levels of aridity by the application of objective standard formulas. The best-known classical method is that of Koppen (1931), who defined dryland regions in terms of an annual precipitation and temperature index. Assuming a mean annual temperature of 18°C, his formula gives a maximum precipitation of 640 mm for semi-aridity with summer rainfall, and 360 mm with winter rainfall, and the calculation that drylands occupy about 26 per cent of the total Earth surface, with the desert region covering 12 per cent and semi-desert and steppes the other 14 per cent. The system was criticized by Mather (1974) for failing to consider water supply and having no physical meaning or indication of the atmospheric processes involved. Water-balance models were developed independently by Penman (1948) and Thornthwaite (1948). Penman’s model is more sophisticated and considers turbulent transfer and energy balance approaches. Thornthwaite’s model considers the energy balance alone, using P, the mean annual precipitation (mm), and a calculation of Pe, the mean annual potential evaporation (mm), in the calculation of a moisture index (Im), resulting in: Im=100[P/Pe−1]. In this system arid regions have an index value of under −66.7, whereas a semi-arid region is defined where Im lies between −33.3 and −66.7. The method was criticized by Wallen (1967) for tending to over-estimate water supplies. Other water-balance methods are reviewed by Jones (1997). The definitive map of the spatial distribution of dryland areas produced by UNEP (1992; see Fig. 1.1) divides the globe on degrees of bioclimatic aridity using the values of the ratio P/PET, that is P=the mean annual precipitation (mm) and PET=the mean annual potential evapotranspiration (mm), as calculated by Penman’s formula. Three categories are relevant here: hyperaridity, where the P/ETP ratio is less than 0.05; aridity, from 0.05

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to 0.20; and semi-aridity, from 0.20 to 0.45. Some classifications of drylands also include the dry sub-humid regions (0.45