A N A L Y S I S A N D I N T E R P R E T A T I O N OF B O T A N I C A L R E M A I N S F R O M S I B U D U C A V E , K W A Z U L U – N A T A L Christine Scott A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Master of Science Department of Archaeology School of Geography, Archaeology and Environmental Studies University of the Witwatersrand Johannesburg, 2005 D E C L A R A T I O N I declare that this thesis is my own, unaided work. It is being submitted for the Degree of Master of Science in the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination in any other University. ……………………… Signature of candidate …….. day of …..…………… 2005 ii A B S T R A C T The identification and analysis of seeds (including fruits and nuts) from second millennium AD deposits at Sibudu Cave, KwaZulu-Natal, constitute the first in-depth archaeobotanical study of seeds in South Africa. The study highlights problems in the reconstruction of past vegetation and climatic variables from seed data. The Sibudu seed assemblage produced no evidence to suggest vegetation change in the Sibudu area during the last 1000 years. Either it is not possible to identify short-term fluctuations in indigenous vegetation from seed data, or the evidence of vegetation change has been masked by the influence of the perennial Tongati River, depositional history, differential preservation and recovery, and identification difficulties. Actualistic studies of seeds on the cave floor, the first of such studies in South Africa, indicated a range of non-human agents of seed accumulation and post-depositional redistribution. Definitive statements about people/plant relationships are problematic because of the number of agents of seed accumulation. iii This dissertation is dedicated to all undaunted researchers who pursue and enjoy archaeobotanical studies. ‘It is by studying little things that we attain the great art of having as little misery and as much happiness as possible’ Samuel Johnson iv A C K N O W L E D G E M E N T S Without the support, encouragement and time given patiently and generously by my supervisor, Prof. Lyn Wadley, this study would not have been initiated or completed. I give her my sincere and grateful thanks. I gratefully acknowledge financial aid from the University of the Witwatersrand Bursary Fund and the National Research Foundation. The research and completion of this dissertation has been a thoroughly enjoyable experience, in large measure because of the liberal assistance from numerous people. Thanks to the many ‘tree’ friends who helped with identification and taught me so much, especially Geoff Nichols. Discussions, academic and less academic, with Lucy Allott, Dr Chet Cain and Gavin Whitelaw were invaluable. My grateful thanks also go to experts in their various fields; Tony Abbott (plant identifications), David Allen (bird feeding habits), Dr Tony Cunningham (ethnographic uses of plants), Frank Jolles (cucurbits), Prof Tom Huffman (Iron Age), Dr David Johnson (bird feeding habits), Don McCulloch (rainfall records), Jim Feeley, Thembi Msomi (ethnographic uses of plants), Dr Henry Moolman (statistics), Dr Ashley Nicholas (seed definitions), Mkhipheni Ngwenya (preparation of herbarium specimens), Bruce Page (ecology), Robyn Pickering (sedimentology), Dr Ina Plug (fauna), David Styles (plant distributions), Dr Peter Taylor (small mammals), Prof. Peter Tyson (climate), Dr Lia Wissing (editing) and Marilee Wood (beads). Thank you too to the South African National Biodiversity Institute (previously the NBI) in Pretoria for allowing me to re- arrange their basement to gain access to parts of the valuable ‘du Plessis’ seed collection. The SANBI is also thanked for the use of plant distribution data from the National Herbarium, Pretoria (PRE) Computerized Information System (PRECIS). I thank Wendy Voorvelt for the section drawings, Brennan Walsh for the maps and the technicians at the Seed Room at Kirstenbosch who shared their expertise. Thank you to my sons Dan and Will for their help and tolerance concerning my computer skills and their patience while I ‘quickly’ collected fruits and vouchers on holiday trips. I thank my mother for her support and my brother J. for the time and v dedication spent in the compilation of bird feeding records (Appendix C). Thank you to my brother Peter and husband Jonathan for construction of the grid squares and to the Keith Scotts for the invaluable microscope. Jack and Ms.T., the faithful canines on many collecting and recording trips, were enthusiastic and reassuring companions. Finally, a very special thanks goes to Jonathan for his moral and financial support of my endeavours and his interest in my work. He had many useful ideas (e.g. about flotation apparatus), made equipment (e.g. a light table) and searched for and purchased numerous essential items (e.g. the flower press and many invaluable books). vi L I S T O F C O N T E N T S page Declaration ................................................................................................................ii Abstract ......................................................................................................................iii Dedication..................................................................................................................iv Acknowledgements .....................................................................................................v Table of Contents .......................................................................................................vii List of Figures ............................................................................................................xi List of Tables..............................................................................................................xii Preface .......................................................................................................................xiii CHAPTER 1 INTRODUCTION AND AIMS .....................................................1 1.1 Aims ...............................................................................................................1 1.2 Description of Cave and Present Environmental Conditions.........................2 1.3 Excavation of Sibudu Cave............................................................................5 1.4 Stratigraphy and Dating of the Second Millennium AD Deposits.................5 1.5 Theoretical Background to Vegetation Change.............................................8 1.5.1 Factors that Influence Vegetation ......................................................8 1.5.2 Determination of the Causative Factors of Specific Vegetation Changes..............................................................................................10 1.5.3 Proxy Climatic Data..............................................................................10 1.6 Previous Ecological Studies...........................................................................11 CHAPTER 2 METHODS......................................................................................12 2.1 Establishment of a Modern Comparative Collection.....................................12 2.1.1 Collection of Seeds and Vouchers .....................................................12 2.1.2 Preparation and Storage of Seeds.......................................................13 2.2 Recovery and Identification of Seeds ............................................................14 2.3 Quantification of Seeds..................................................................................15 vii CHAPTER 3 DISCUSSION OF METHODS......................................................16 3.1 Recovery Methods and the Effects on Assemblage Composition .................16 3.1.1 Effect of Sampling on the Recovery of Seeds ...................................17 3.1.2 Suitability of Flotation vs. Dry Sieving for Recovery of Seeds.........22 3.1.3 Effect of Sieve Mesh Size on Recovery of Seeds..............................23 3.1.4 Effect of Preservation on Recovery of Seeds.....................................24 3.1.5 Effect of Agents of Deposition and Post-Deposition.........................25 3.2 Identification of Seeds ...................................................................................25 3.2.1 Establishment of a Comparative Seed Collection..............................25 3.2.2 Difficulties caused by Similarities between Taxa..............................26 3.2.3 Effect of Preservation on Identification of Seeds ..............................27 3.3 Interpretation of Results.................................................................................27 3.3.1 Determination of Absolute Counts ....................................................27 3.3.2 Frequency Measurements and Statistics ............................................30 CHAPTER 4 RESULTS........................................................................................36 4.1 Qualitative Results .........................................................................................36 4.1.1 Absence/Presence of Taxa .................................................................36 4.1.2 Seasonality of Species........................................................................44 4.2 Quantitative Results .......................................................................................46 4.2.1 Frequencies