The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgementTown of the source. The thesis is to be used for private study or non- commercial research purposes only. Cape Published by the University ofof Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. University NATURAL AND HUMAN INDUCED LATE QUATERNARY ENVIRONMENTAL CHANGE ON THE NOORDHOEK VALLEY, CAPE TOWN, SOUTH AFRICA BY EU AKUNJI Town Submitted in fulfilment of the requirementsCape for the degree of MASTERS OF ARTS of Department of Environmental and Geographical Science UNIVERSITY OF CAPE TOWN University Rondebosch 7701 South Africa August 2004 THE NOORDHOEK VALLEY ~~~==--~--~-- ------------------~ Town Cape of FRONTISPIECE: lake Michelle and the twin Wildevoelvleis in the background University(Photo: E. Akunji, July 2004) ABSTRACT This research project attempts to determine the relative influences of climate. sea level changes and human activities during the period of sediment accumulation in the Noordhoek basin in the southwestern Cape. South Africa. The research relies on lacustrine sedimentary deposits and their compositional changes as evidence of the dynamic depositional environments from which environmental conditions are inferred. Data on spatial changes on land surfaces have also been employed to complement the sedimentary chronology from catchments beyond historic records. Assessment of the extent of human influence on the Noordhoek basin has been achieved through comparison with the pristine conditions found on the Cape Nature Reserve. Analysis of dated sediment cores from the Noordhoek valley and the Cape Peninsula Nature reserve has facilitated the reconstruction of major environmental changes for the late Pleistocene and Holocene periods. An extended record of environmental change from the longest core (LM~Core) has enabled environmental reconstruction and the determination of the relative influences of climate, sea level change and human activities on the loca! environment of the basin during the late Quaternary. Sedimentological evidence from the cores reveals the long-term evolution of the wetlands as being influenced by fluctuating sea levels and climate change until the mid Holocene. Short-term environmental processes during the late Holocene. resulting from direct anthropogenic activities such as irrational uses of the wetlands for agriculture and urbanisation are responsible for polluting and transforming the status of the wetlands. Heavy metal concentrations in sediment cores from the twoTown Noordhoek wetlands have allowed the elucidation of recent human impacts. The vertical distribution of these metals correlates with and complements the evidence of spatial changes in land use and land cover. Metal enrichment in the modern Noordhoek wetland sediments and increased organic matter content indicates increasing anthropogenic impacts on the valley as agricultureCape and urbanisation increased. In comparison. there is a much lower concentration of heavy metals at Groot Rondevlei, as its catchment has been lessof prone to severe local disturbance such as urban development and recent agricultural activities. The absence of a tightly resolved chronology for these cores restricts the understanding of the commencement and duration of major environmental changes, which have been accounted for elsewhere in the region. This limits the opportunity for direct comparison between this and other known sites. However, the Noordhoek valley is a potential resource for longer-term Quaternary environmental study.University The application of a multi-disciplinary approach and high­ resolution dating are highly recommended for future research in this area. EU AKUNJI University of Cape Town I Acknowledgements I sincerely wish to give thanks to all who assisted me throughout this project: .:. Foremost I am deeply indebted to my supervisors. Firstly. I thank Professor Mike Meadows for his overwhelming patience, advice and enthusiasm for all aspects of this research. Special thanks to you Mike for financing the fieldworks, cartography and dating of the sediments. Secondly, I acknowledge Professor Peter J. Holmes for his advice and assistance. especially during the early stages of the research. I appreciate your time and effort in assisting me locate the study sites . •:. Thanks are due to Dr. John Rogers, Assoc. Prof. John Compton. Dr. Roychoudhury, Andreas Spath and Ms. Meris Smith of the Department of Geological Sciences, Mrs Shirley Butcher. Brett Smith in Environmental and Geographical Science and Brian Chase of Sheffield University . •:. I thank Michelle Walker of the South Peninsula Municipality and Glenn Ashton of Noordhoek Environmental Group for the supply of valuable information. And New Era Coaching Africa for printing of this thesis . •:. Thanks to Sayed Hess, Mrs. Sharon Adams, Mrs. Mandy Innes and Mr Tony George (Departmental of Environmental and Geographical Science) for their willingness to assist with logistical aspects of the project. .:. To the university of cape Town for granting me the INTER Schoraship . •:. To Dr. Gideon Akunji and the family without whom I wouldTown never have had university education. I thank you for the financial and moral support. Your encouragement all along and most especially during the last quarter when I thought my social life was crumbling. You directed me toward God in whom I found everlasting security and protection.Cape To Him be the glory . •:. To the entire Akunji family resident in Cameroon thanks a lot for your love and encouragement. Your prayers helpedof me through. I love you all . •:. To sister Mary for her support throughout my undergraduate years when a Master degree was a lifetime dream, but her encouragement made it a reality. Thanks sister for your endless hospitality and jokes. I miss you . •:. Lastly, I thank my friends Vicky Stevens, Kennedy Efugenum, Emmanuel Mbakwa, Ayuk James, Itoe Maurice, Taku Philippian, Wan'Mbuta, and Thato MonsteUniversity for their tireless support during the course of this research . •:. Above all, I joyfully dedicate this thesis to Jesus Christ who has been a source of strength and inspiration to my family and I for all these years. EU Akunji University of Cape Town II CONTENTS ABSTRACT ACKNOWLEDGEMENTS II CONTENTS III LIST OF APPENDICES VII LIST OF FIGURES IX LIST OF TABLES X LIST OF PLATES XI CHAPTER 1 INTRODUCTION 1.1 INTRODUCTION 1 1.2 BACKGROUND TO STUDY AREA 3 1.3 SIGNIFICANCE OF NOORDHOEK WETLANDS AS STUDY SITES 5 1.4 RATIONAL FOR STUDY 6 1.5 RESEARCH QUESTIONS 7 1.6 AIMS AND OBJECTIVES Town 8 1.7 THESIS OUTLINE 9 CHAPTER 2 NATURAL AND ANTHROPOGENIC LATE QUATERNARY ENVIRONMENTAL CHANGE Cape 2.1 INTRODUCTION of 10 2.2 RATIONALE FOR RECONSTRUCTING LATE QUATERNARY ENVIRONMENTS 11 2.3 SEDIMENTS IN ENVIRONMENTAL RECONSTRUCTION 12 2.3.1 Applications and limitations in using sediments 13 2.4 SOUTHERN UniversityAFRICA QUATERNARY ENVIRONMENTAL CHANGE 15 2.5 LATE QUATERNARY ENVIRONMENTAL CHANGE IN THE SOUTHWESTERN CAPE 17 2.5.1 Spatial and temporal climatic chronology 18 In 2.6 LAND USE AND LAND COVER CHANGES 22 2.6.1 Land use and land cover change in the southwestern Cape region 23 2.6 CURRENT AND POTENTIAL IMPACTS OF LAND USE CHANGE AND URBANISATION 24 2.7.1 Hydrology and Erosion 25 2.7.2 Pollution 26 2.7.3 Vegetation 27 2.7 CONCLUSION 28 CHAPTER 3 CONTEMPORARY VLEI ENVIRONMENT OF THE NOORDHOEK VALLEY 3.1 INTRODUCTION 29 3.2 THE SOUTHERN CAPE PENINSULA REGION 29 3.3 PHYSICAL CHARACTERISTICS OF THE STUDY REGION 30 3.3.1 Geology, geomorphology and soils 32 3.3.2 Contemporary climate 37 3.3.3 Hydrology 41 3.3.4 The wetlands 42 3.3.4 Vegetation Town 46 3.4 CONCLUSION 51 CHAPTER 4 MEDTHODOLOGY AND LABORATORY TECHNIQUES 4.1 INTRODUCTION Cape 53 4.2 IDENTIFYING STUDY LOCALITIESof 54 4.3 CORING TECHNIQUES 55 4.3.1 Elevations 57 4.4 LABORATORY ANALYSIS OF SEDIMENTS 58 4.4.1 Physical analysis 58 4.4.2 MineralogyUniversity 59 4.4.3 Munsell notations 59 4.4.4 Dating 59 IV 4.5 CHEMICAL ANALYSIS 60 4.5.1 pH 60 4.5.2 CQf1(juetivity 61 4.5.3 Total organic fraction 61 4.0 GEOCHEMICAL ANALYSIS 61 4.7 SPATIAL LAND USE AND LAND COVER CHANGE 63 4.7.1 Data acquisition 62 4.7.2 Image processing 62 4.7.3 Analysis 64 4.8 STATISTICAL TECHNIQUES 65 4.8.1 Principal component analysis 65 4.8.2 Normalisation of geochemical data 66 4.9 CONCLUSION 66 CHAPTER 5 SEDIMENTOLOGY, GEOCHEMISTRY AND SPATIAL LAND USE IN THE NOORDHOEK VALLEY 5.1 INTRODUCTION 67 5.2 SEDIMENTOLOGICAL AND GEOCHMENICAL EVIDENCE 67 Town 5.2.1 Lake Michelle Core (LM·Core) 67 5.2.2 Wildevoelvlei Core (WV- Core) 76 5.2.3 Groot Rondevlei Core (GR·Core) 84 5.3 TIME SERIES SPATIAL LAND USE/COVERCape CHANGE 91 5.3.1 Introduction of 91 5.3.2 Patterns in agricultural land use changes 9; 5.3.3 Patterns in urban land use changes 92 5.3.4 Patterns in vegetation (alien dominated) change 93 5.3.5 Patterns in vegetation (fynbos dominated) change 93 5.3.6 Beach and sand dunes 94 5.3.7 Waterbodies 94 5.4 CONCLUSIONUniversity 97 v CHAPTER 6 PALAEOENVIRONMENTAL RECONSTRUCTION 6.1 INTRODUCTION 98 6.1.1 Regional synthesis 98 6.2 STRATIGRAPHY AND CHRONOLOGY 100 6.2.1 LM-Core 100 6.2.2 WV-Core 107 6.2.3 GR-Core 111 6.3 GEOCHEMICAL IMPLICATIONS 112 6.4 DEVELOPMENT OF THE NOORDHOEK COASTAL LANDFORMS 113 6.4.1 Upper Pleistocene development 113 6.4.2 Holocene 114 6.4.3 Evolution of the Noordhoek wetlands 115 6.5 ANTHROPOGENIC INFLUENCE ON THE NOORDHOEK VALLEY 116 6.5.1 Surface pollution 116 6.5.2 Land use and land cover change 118 6.6 CONCLUSION