University of Cape Town Faculty of Science Department of Botany THESIS Submitted in fulfilment of the requirements for the degree of Master of Philosophy (Botany) January 2009 An environmental history of the Cederberg: changing climate, land use and vegetation patterns Daniela Vincenza Bonora Supervisors: Prof. Timm Hoffman (Botany, UCT), Dr. Rick Rohde (Centre of African Studies, University of Edinburgh) and Dr. Edmund February (Botany, UCT) ii PLAGIARISM DECLARATION 1. I know that plagiarism is wrong. Plagiarism is to use another’s work and pretend that it is my own. 2. Each contribution to, and quotation in this research report from the work(s) of other people has been contributed, and has been cited and referenced. 3. This research report is my own work and has not previously in its entirety or in part been submitted at any other university for another degree. 4. I have not allowed, and will not allow, anyone to copy my work with the intention of passing it off as his or her own work. Signature: Date: iii An environmental history of the Cederberg: changing climate, land use and vegetation patterns Daniela Vincenza Bonora BNRDAN001 THESIS Submitted in fulfilment of the requirements for the degree of Master of Philosophy (Botany) January 2009 iv - TABLE OF CONTENTS - ACKNOWLEDGEMENTS ................................................................................................................. v ABSTRACT .......................................................................................................................................... vi CHAPTER 1: General Introduction ................................................................................................... 1 1.1 BACKGROUND AND MOTIVATION FOR RESEARCH ....................................................... 1 1.2 OBJECTIVES ................................................................................................................................. 5 1.2.1 Project Aims ............................................................................................................................. 5 1.2.2 Key Questions ........................................................................................................................... 5 1.3 LIMITATIONS OF RESEARCH ................................................................................................. 5 1.4 THESIS STRUCTURE .................................................................................................................. 6 CHAPTER 2: The Cederberg Environment in Space and Time ...................................................... 8 2.1 INTRODUCTION ........................................................................................................................... 8 2.2 THE GEOLOGY AND GEOMORPHOLOGY OF THE CEDERBERG ................................. 8 2.3 SOILS ............................................................................................................................................. 12 2.4 CLIMATE ..................................................................................................................................... 12 2.4.1 Palaeoclimates of the Cederberg and Southern Western Cape ......................................... 13 2.4.2 Historical Trends in Climate ................................................................................................. 15 2.4.2.1 Rainfall ........................................................................................................................ 15 2.4.2.2 Temperature ................................................................................................................ 16 2.4.2.3 Evaporation ................................................................................................................. 17 2.5 FIRE ............................................................................................................................................... 18 2.6 VEGETATION: BIOMES AND BIOREGIONS ....................................................................... 19 2.6.1 The Fynbos Biome .................................................................................................................. 19 2.6.2 The Succulent Karoo Biome ................................................................................................. 20 2.6.3 The Vegetation and Flora of the Cederberg ........................................................................ 21 2.7 A CHRONOLOGY OF OCCUPATION .................................................................................... 26 2.7.1 Pre-Colonial History .............................................................................................................. 26 2.7.2 Early Colonial History .......................................................................................................... 27 2.7.3 The Twentieth Century ......................................................................................................... 29 CHAPTER 3: The Intensification of Land Use in the Lowlands of the Cederberg During the 20th Century ................................................................................................................................................ 30 3.1 INTRODUCTION ......................................................................................................................... 30 ii 3.2 AGRICULTURE AT A PROVINCIAL, DISTRICT AND MUNICIPAL SCALE ................ 31 3.2.1 The Western Cape Province .................................................................................................. 31 3.2.2 West Coast District Municipality ......................................................................................... 34 3.2.3 Cederberg Local Municipality .............................................................................................. 34 3.3 METHODS .................................................................................................................................... 35 3.4 RESULTS ...................................................................................................................................... 36 3.4.1 Population ............................................................................................................................... 36 3.4.2 Livestock ................................................................................................................................. 37 3.4.3 Cultivation .............................................................................................................................. 38 3.5 DISCUSSION ................................................................................................................................ 44 CHAPTER 4: Photographic Evidence and Local Interpretations of 20th Century Landscape Change in the Cederberg Wilderness Area ...................................................................................... 48 4.1 INTRODUCTION ......................................................................................................................... 48 4.2 METHODS .................................................................................................................................... 49 4.3 RESULTS ...................................................................................................................................... 51 4.4 DISCUSSION ................................................................................................................................ 63 4.4.1 Changes in Plant Cover and Species Composition ............................................................. 63 4.4.2 Anthropogenic Impacts ......................................................................................................... 64 4.4.2.1 Settlement .................................................................................................................... 64 4.4.2.2 Cultivation ................................................................................................................... 65 4.4.2.3 Livestock ...................................................................................................................... 66 4.4.2.4 Fire .............................................................................................................................. 67 4.4.3 Climate Change and Land Use Impacts .............................................................................. 68 4.4.4 Future Land use ..................................................................................................................... 69 4.4.5 Synthesis ................................................................................................................................. 70 CHAPTER 5: The Decline of the Endemic Clanwilliam Cedar (Widdringtonia cedarbergensis) Over the Last 75 Years as Revealed by Historical Photographs .................................................... 71 5.1 INTRODUCTION ......................................................................................................................... 71 5.2 METHODS .................................................................................................................................... 74 5.2.1 Field Sampling ....................................................................................................................... 74 5.2.2 Photographic and Statistical Analyses ................................................................................. 75 5.2.3 Fire .........................................................................................................................................