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April 2007 A Record of Environmental and Climatic Change from the West Coast, South Island, New Zealand, using Beetle Fossils A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in Geology in the University of Canterbury by Philip I. Burge i Contents List of Figures viii List of Tables xii Abstract 1 Acknowledgements 3 Chapter 1 Introduction 5 1.1 Background 5 1.2 Thesis Aims & Objectives 8 1.3 Modern physiography 10 1.3.1 Regions of the West Coast 10 1.3.2 Physiography & geology 12 1.3.3 Climate 13 1.3.4 Vegetation 14 1.4 Beetles as palaeoclimatic and palaeoenvrionmental proxies 16 1.4.1 An introduction to the New Zealand beetle fauna 17 1.4.2 The evolutionary constancy of beetles 20 1.4.3 The history of fossil beetles as palaeoenvironmental and palaeoclimatic indicators 26 1.4.4 Potential problems with beetles as palaeoclimatic indicators 33 1.5 Vegetation history of the West Coast since the penultimate (Waimea) glaciation 39 1.6 Thesis Layout 45 Chapter 2 Methods for palaeoclimatic and palaeoenvironmental ii reconstructions 47 2.1 Site selection 47 2.2 Sample collection, processing and identification 49 2.3 Age control 51 2.4 Palaeoclimatic and palaeoenvironmental reconstructions 51 Chapter 3 Environmental and climatic factors controlling the distribution of the New Zealand beetle fauna: A test of the assumptions underlying the use of fossil beetles as palaeoclimatic proxies 54 3.1 Introduction 54 3.2 Methods 56 3.3 Results 59 3.4 Discussion 68 3.4.1 Weaknesses in the data-set 68 3.4.2 The factors controlling beetle distribution 69 3.5 Conclusions 75 Chapter 4 The palaeoclimate and palaeoenvironment of the Westport region during the mid-Holocene (ca. 5.8ka BP): Evidence from Alma Road 79 4.1 Introduction 79 4.1.1 Modern physiography 79 4.2 Methods 82 4.3 Results 82 4.3.1 Summary stratigraphy & chronology 82 4.3.2 Palaeoenvironmental reconstruction 84 4.3.3 Palaeoclimatic reconstruction 85 4.4 Discussion 87 4.4.1 Stratigraphic interpretation 87 iii 4.4.2 Outlying taxa 87 4.4.3 Palaeoenvironment 91 4.4.4 Palaeoclimate 91 4.5 Conclusions 94 Chapter 5 The palaeoclimate and palaeoenvironment of the Westport region between 74 and 40ka BP: Evidence from Keoghan’s Road 95 5.1 Introduction 95 5.1.1 Modern physiography 95 5.2 Methods 98 5.3 Results 100 5.3.1 Summary stratigraphy 100 5.3.2 Chronology of the Keoghan’s Road site 102 5.3.3 Palaeoenvironment and palaeoclimate of unit KR-A3 102 5.3.4 Palaeoenvironment and palaeoclimate of unit KR-B2 109 5.4 Discussion 116 5.4.1 Stratigraphic interpretation 116 5.4.2 Age control 117 5.4.3 Outlying taxa 119 5.4.4 Palaeoclimate, palaeoenvironment and the presence of refugia between 74-40ka BP 121 5.4.5 Moisture 124 5.4.6 Seasonality 125 5.5 Conclusions 126 Chapter 6 The palaeoclimate and palaeoenvironment of the Westport region between 37 and 21ka BP: Evidence from Wilson’s Lead Road 128 iv 6.1 Introduction 128 6.1.1 Modern physiography 129 6.2 Methods 131 6.3 Results 132 6.3.1 Summary stratigraphy 132 6.3.2 Chronology of “the Hill”, Wilson’s Lead Road 132 6.3.3 Palaeoenvironment 136 6.3.4 Palaeoclimate 149 6.4 Discussion 164 6.4.1 Age control 164 6.4.2 Environmental reconstruction and comparison to the pollen record from WLR 165 6.4.3 Palaeoclimate discussion 178 6.4.4 Types of glacial event 197 6.4.5 Seasonality 201 6.5 Conclusions 203 6.5.1 Palaeoenvironment 204 6.5.2 Palaeoclimate 205 Chapter 7 Discussion 207 7.1 Advances in understanding glacial age palaeoecology and wider implications 207 7.1.1 Glacial age Nothofagus beech refugium in the northwest South Island 209 7.1.2 Glacial age vegetation mosaics in the northwest South Island 212 7.1.3 Reasons for the lack of arboreal pollen in glacial age pollen diagrams 214 7.1.4 Pollen production during OIS 4 but not OIS 2? 217 7.2 Constraints on beetle distribution in New Zealand 219 v 7.2.1 Winter versus summer temperatures 220 7.2.2 Precipitation 222 7.2.3 Alternative to ecological preferences as a limitation 223 7.3 Advances in understanding glacial age palaeoclimates and wider implications 224 7.3.1 The timing of Southern Hemisphere glacial cooling 225 7.3.2 Multiple mechanisms for Southern Hemisphere mid-latitude glacial advance & linkages to regional patterns of insolation 228 7.3.3 Seasonality 230 Chapter 8 Limitations, Directions for Future Research & Final Conclusions 232 8.1 General limitations with palaeoentomological research in New Zealand 232 8.1.1 Lack of data on New Zealand beetle distributions and the inclusion of phyophagus taxa in palaeoclimatic reconstructions 232 8.1.2 The problem of rare taxa in palaeoclimatological studies 234 8.1.3 Need to better understand New Zealand beetle ecology and physiology 235 8.1.4 Problems identifiying taxa to species level and the effect on palaeoclimatic reconstructions 236 8.2 Further Areas of Research 238 8.2.1 Palaeoclimate 238 8.2.2 Palaeoenvironment 243 8.3 Final Conclusions 245 References 248 Appendices 282 vi Appendix 1. Pilot fossil beetle sites 282 Appendix 2. Taxonomic composition of fossil taxa used in this thesis 300 Appendix 3. List of fossil taxa used in final ordination analysis (Chapter 3) 309 Appendix 4. Pollen counts from Keoghan’s Road samples (Chapter 5) 311 Appendix 5. Summary table of all dates used for age control on the sites examined in this thesis (Chapters 4-6) 313 Appendix 6. Papers submitted from this thesis 314 A6.1 An OIS 5a to OIS 4 environmental and climatic reconstruction from the northwest South Island, New Zealand, using beetle fossils. 315 A6.2 Re-envisioning the structure of vegetation during the last glaciation in New Zealand: A beetle’s eye view. 355 Electronic Appendix MLE spreadsheets and collection localities for taxa included CD vii List of Figures Chapter 1 Figure 1.1a Position of New Zealand in relation to atmospheric circulation 6 Figure 1.1b Position of New Zealand in relation to Southern Hemisphere zonal mean zonal wind flow 6 Figure 1.2 Major geographic divisions used in this thesis 10 Figure 1.3 North Westland Ecological Region and Ecological Districts 15 Figure 1.4 Illustration of beetle indicating commonly preserved skeletal elements 20 Figure 1.5 Example MCR plot 30 Figure 1.6 Example MLE plot 34 Figure 1.7 Location of pollen records mentioned in text 41 Chapter 2 Figure 2.1 Location of pilot sites sampled for fossil beetles 48 Chapter 3 Figure 3.1 CCA plot of the nine significant environmental variables controlling beetle distribution in New Zealand 62 Figure 3.2 Location of the collection sites at which taxa used in statistical analysis were collected 64 Figure 3.3 Pie graph showing variance partitioning of total explained variation in beetle collection data 65 Chapter 4 Figure 4.1 Location of Alma Road site and other sites mentioned in text 80 Figure 4.2 Stratigraphic summary of Alma Road site 83 Figure 4.3a Alma Road mean summer temperature reconstruction 86 Figure 4.3b Alma Road mean daily minimum winter temperature reconstruction 86 Figure 4.4 Alma Road mean annual precipitation reconstruction 88 viii Figure 4.5 Collection localities of Tormus nitidulus Broun and Leiodidae unknown sp. 1. 90 Chapter 5 Figure 5.1 Location of Keoghan’s Road site and other sites mentioned in text 96 Figure 5.2 Stratigraphic summary of Keoghan’s Road site 99 Figure 5.3a Keoghan’s Road KR-A3 sample mean summer temperature reconstruction 107 Figure 5.3b Keoghan’s Road KR-A3 sample mean daily minimum winter temperature reconstruction 107 Figure 5.4 Keoghan’s Road KR-A3 sample mean annual precipitation reconstruction 108 Figure 5.5 Keoghan’s Road KR-B2 sample mean summer temperature reconstruction 113 Figure 5.6 Keoghan’s Road KR-B2 sample mean daily minimum winter temperature reconstruction 114 Figure 5.7 Keoghan’s Road KR-B2 sample mean annual precipitation reconstruction 115 Chapter 6 Figure 6.1 Location of Wilson’s Lead Road site and other sites mentioned in text 130 Figure 6.2 Stratigraphic summary of Wilson’s Lead Road site 133 Figure 6.3 Age-depth diagram of sampled organic silt unit at Wilson’s Lead Road 135 Figure 6.4 Composition of sample beetle assemblages by habitat type 146 Figure 6.5 Wilson’s Lead Road conservative climate reconstructions on time scale 151 Figure 6.6a Wilson’s Lead Road mean daily minimum winter temperature reconstructions samples H1-H6 153 Figure 6.6b Wilson’s Lead Road mean daily minimum winter ix temperature reconstructions samples H7-H11 154 Figure 6.6c Wilson’s Lead Road mean daily minimum winter temperature reconstructions samples H12-H17 155 Figure 6.7a Wilson’s Lead Road mean summer temperature temperature reconstructions samples H1-H6 156 Figure 6.7b Wilson’s Lead Road mean summer temperature temperature reconstructions samples H7-H11 157 Figure 6.7c Wilson’s Lead Road mean summer temperature temperature reconstructions samples H12-H17 158 Figure 6.8a Wilson’s Lead Road mean annual precipitation temperature reconstructions samples H1-H6 159 Figure 6.8b Wilson’s Lead Road mean annual precipitation temperature reconstructions samples H7-H11 160 Figure 6.8c Wilson’s Lead Road mean annual precipitation temperature reconstructions samples H12-H17 161 Figure 6.9 Wilson’s Lead Road climate reconstructions on time scale 162 Figure 6.10 Wilson’s Lead Road pollen diagram 166 Figure 6.11 Comparison of summary pollen and beetle fossil environmental reconstructions 167 Figure 6.12 Idealised transect of vegetation structure at Wilson’s Lead Road site during OIS 3 169 Figure 6.13 Idealised transect of vegetation structure at Wilson’s Lead Road site during OIS 2 171 Figure 6.14