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Durham E-Theses Palaeobiogeography of Crossbills (Loxia spp.) and their Food Plants HOLLIDAY, PHYLLIDA,RACHEL How to cite: HOLLIDAY, PHYLLIDA,RACHEL (2012) Palaeobiogeography of Crossbills (Loxia spp.) and their Food Plants, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/3636/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Palaeobiogeography of Crossbills (Loxia spp.) and their Food Plants Phyllida Rachel Holliday Masters by Research School of Biological and Biomedical Sciences Durham University 2011 Illustrations of the Scottish Crossbill, Loxia scotica (left) and Parrot Crossbill, Loxia pytyopsittacus (right), created by P. R. Holliday. Phyllida Holliday 2012 Phyllida Holliday 2012 Palaeobiogeography of Crossbills (Loxia spp.) and their Food Plants Phyllida Rachel Holliday Abstract Crossbills (Loxia spp.) are members of the finch family (Fringillidae) and have a primarily granivorous diet, feeding on the seeds of conifers, specifically members of the family Pinaceae. Studies of the five extant crossbill species are abundant due to the distinctive evolution of their crossed mandibles, specifically adapted for a coniferous seed diet. Many have attempted to understand their evolutionary origins and speciation but the complexity of Loxia’s phylogeography and movement patterns have made it difficult to gain an accurate understanding. Although many hypotheses have been proposed, substantial evidence has yet to be found. This study aims investigates the palaeobiogeography of the five species of crossbill, as well as their specific food trees, in order to better understand their past movements and the impacts of these on the evolutionary history of the genus. By combining several different techniques of climate-based niche modelling with global palaeoclimatic simulations, potential ranges of crossbills and their food plants have been simulated for the last 120 thousand years. These simulations have also been compared to available crossbill fossil records, pollen data and other palaeovegetation models. The results indicate that significant species’ specific population range shifts are likely to have occurred in response to climatic change throughout this period. The simulations have provided valuable insight into the evolution of Loxia taxa, particularly isolated island populations or races, supporting existing evolutionary theories in addition to introducing novel hypotheses. Phyllida Holliday 2012 Phyllida Holliday 2012 Table of Contents Page no. List of Tables 1 List of Figures 2 Abbreviations 7 Declaration of Copyright 8 Acknowledgements 8 Chapter 1 Palaeobiogeography of Crossbills (Loxia spp.) and their Food Plants 9 1.1 Crossbill (Loxia genus) Range and Diet 10 Loxia curvirostra 10 Loxia leucoptera 13 Loxia pytyopsittacus 15 Loxia scotica 16 Loxia megaplaga 17 1.2 The Phylogenetics of the Crossbill 18 1.3 The Fossil Record of the Crossbill 20 1.4 Evolution of the Crossbill 23 1.5 Anthropogenic Impacts on Species’ Distribution 26 1.6 Quaternary Climate and Species’ Response 30 1.7 Species’ Distribution Modelling 32 1.8 Aims & Objectives 39 Chapter 2 Data Collection & Methods 37 2.1 Species’ Distribution Data 37 2.2 Bioclimatic Data 40 2.3 Palaeobioclimatic Data 42 2.4 Modelling Approaches 47 Maximum Entropy 47 Generalised Additive Model 48 Climate Response Surface 49 2.5 Model Thresholds & Evaluation 52 2.6 Modelling Grid Extent 56 2.7 Mapping 58 Chapter 3 Results 60 3.1 Species’ Distribution Model Performance 60 ‘Goodness of Fit’ 60 ‘Robustness’ 65 3.2 Comparison of Model Simulations of Species’ Distribution 70 Present simulation 71 Beginning of the Holocene 73 Last Glacial Maximum 75 Heinrich Event 5 77 Interstadial 79 Melisey 1 stadial 81 Eemian Interglacial 83 Phyllida Holliday 2012 3.3 Comparison of Model Simulations of Species’ and Genera’s Range Size 85 Loxia curvirostra 85 Loxia leucoptera 86 Loxia pytyopsittacus 87 Loxia scotica 88 Loxia megaplaga 89 Larix spp. 90 Picea spp. 91 Pinus spp. 92 Pseudotsuga spp. 93 Tsuga spp. 94 Picea abies 95 Pinus sylvestris 96 Pinus occidentalis 97 3.4 Observed Compared with Simulated Range 98 Loxia curvirostra 98 Loxia leucoptera 101 Loxia pytyopsittacus 103 Loxia scotica 105 Loxia megaplaga 107 Larix spp. 109 Picea spp. 113 Pinus spp. 115 Pseudotsuga spp. 119 Tsuga spp. 121 Picea abies 123 Pinus sylvestris 126 Pinus occidentalis 129 3.5 Species’ Palaeo-Simulations and Duration of Occupation 131 Loxia curvirostra 133 Loxia leucoptera 137 Loxia pytyopsittacus 141 Loxia scotica 144 Loxia megaplaga 146 Larix spp. 151 Picea spp. 157 Pinus spp. 161 Pseudotsuga spp. 167 Tsuga spp. 171 Picea abies 175 Pinus sylvestris 179 Pinus occidentalis 183 Chapter 4 Discussion & Conclusions 187 4.1 Evaluation of Species’ Distribution Models 187 4.2 Comparison of Crossbill Simulations with Fossil Records 191 4.3 Comparison of Conifer Simulations with Pollen Records and Palaeovegetation Models 194 Pollen Records 194 Larix/Pseudotsuga spp. 195 Picea spp. 198 Pinus spp. 200 Tsuga spp. 202 Phyllida Holliday 2012 Palaeovegetation Models 203 Larix spp. 204 Picea abies 205 Pinus sylvestris 207 4.4 Comparison of Crossbill Simulated Ranges with their Simulated Feeding Tree Range 210 Loxia curvirostra and their feeding trees 211 Loxia leucoptera and Larix spp. 213 Loxia pytyopsittacus, L. scotica and Pinus sylvestris 215 Loxia megaplaga and Pinus occidentalis 217 4.5 Dispersal Distances of Crossbills 219 4.6 Insights into Crossbill Evolution 221 Loxia curvirostra 221 Loxia leucoptera 222 Loxia pytyopsittacus 223 Loxia scotica 224 Loxia megaplaga 225 4.7 Conclusions 227 Appendix 230 References 281 Phyllida Holliday 2012 List of Tables Chapter 1 – Background Knowledge Page no. 1.1.1 Loxia curvirostra (Common Crossbill) subspecies and distributions 10 1.1.2 Feeding tree species of Loxia curvirostra and subspecies 12 1.1.3 Feeding tree species of Loxia leucoptera 14 1.1.4 Loxia leucoptera (Two-Barred Crossbill) subspecies and distributions 14 1.1.5 Feeding tree species of Loxia pytyopsittacus and L. scotica 15 1.1.6 Feeding tree species of Loxia megaplaga 17 1.3.1 Locations of Loxia genus fossil sites 20 1.5.1 A comparison of the presence and breeding records for Loxia curvirostra and L. scotica 28 collected in 1968-72 and 1988-91 1.5.2 ID localities where Loxia curvirostra has established a breeding colony 29 Chapter 2 – Data Collection & Methods 2.1.1 The selection of Larix & Picea species, their distribution in the world and the data source 37 2.1.2 The selection of Pinus, Pseudotsuga & Tsuga species, their distribution in the world and the 38 data source 2.5.1 A confusion matrix for evaluation the ‘Goodness of Fit’ 52 2.5.2 Assessment criteria for the model performance based on the maximum κ value obtained 53 2.5.3 Assessment criteria for the model performance based on the Area Under Curve (AUC) value 54 obtained 2.7.1 The estimated sea-levels below present day for present day to 120,000 years before present 58 Chapter 3 – Results 3.1.1 The ‘Goodness of Fit’ measures for the Loxia species 60 3.1.2 The ‘Goodness of Fit’ measures for the tree genera/species 61 3.1.3 The ‘Goodness of Fit’ measures obtained for the European and Caribbean restricted species 64 3.1.4 The average ‘Goodness of Fit’ measures obtained by k-cross validation tests of robustness 66 for Loxia species 3.1.5 The average ‘Goodness of Fit’ measures obtained by k-cross validation tests of robustness 67 for the tree species/genera 3.1.6 The average ‘Goodness of Fit’ measures obtained by k-cross validation tests of robustness 68 for species modelled on the European and Caribbean bioclimatic grids 3.2.1 The total number of grid cells the models individually or combined simulated as suitable for 70 Loxia curvirostra in each of the scenarios 3.5.1 The total number of grid cells grouped by the species’/genus’ duration of simulation 132 Chapter 4- Discussion and Conclusions 4.1.1 The variance of the simulated range sizes produced by the species’ distribution models 188 4.5.1 Ringing records for Loxia species 219 1 Phyllida Holliday 2012 List of Figures Chapter 1 – Background Knowledge Page no. 1.1.1 Distribution of Loxia curvirostra 10 1.1.2 Distribution of Loxia leucoptera 13 1.1.3 Distribution of Loxia pytyopsittacus 15 1.1.4 Distribution of Loxia scotica 16 1.1.5 Distribution of Loxia megaplaga 17 1.2.1 Plot based on AFLP scores for individual Loxia specimens analysed in the study 18 1.3.1 Locations of fossil records of crossbills (Loxia spp.) in Europe 21 1.5.1 Breeding records for Loxia curvirostra and L. scotica between 1968 and 1972 in 28 Britain and Ireland 1.5.2 Breeding records for Loxia curvirostra and L. scotica between 1988 and 1991 in 28 Britain and Ireland 1.5.3 The distributions of Loxia curvirostra breeding populations in the United Kingdom 29 1.6.1 The variation in temperature compared to present day 30 Chapter 2 – Data Collection & Methods 2.3.1 The mean bioclimatic values for the palaeoclimatic scenarios calculated for the 43 northern hemisphere extensive grid Equation 2.4.1 GAM Response transformation 49 2.4.2 A summary of the different methods of extrapolation in ‘no-analogue’ 51 environmental conditions Equation 2.51 Calculation of maximum κ values 52 Chapter 3 - Results 3.1.1 The effect of species’ range size on the calculated maximum κ values 62 3.1.2 The effect of species’ range size on the calculated AUC values.