What Factors Influence the Success of Senecio (Asteraceae) in Canterbury, New Zealand? A Phylogenetic and Ecological Study. A thesis submitted in partial fulfilment of the requirements for the Degree Master of Science in Ecology University of Canterbury By Andrew Edmund Memory University of Canterbury 2012 1 “It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change.” - Charles Darwin 2 Acknowledgements First and foremost I would like to thank my supervisors: Dr Pieter Pelser, Dr Jon Sullivan and Professor Dave Kelly for their support, patience and encouragement throughout the construction of this manuscript. Without them this project would not have seen the light of day. I would also like to thank Maggie Tisch, Craig Galilee, Matt Walters, Jenny Ladley and Reijel Gardiner for their technical experience which proved invaluable during the study. I would also like to thank Jack van Berkel for allowing me to stay at field stations throughout the Canterbury region, while I conducted my field work. Special thanks to my family whose constant support has been unwavering throughout my study and has allowed me to perform at my best. I also reserve special thanks to Nick Etheridge and especially Kylie Legg, whose help and enthusiasm allowed me to conduct a second field season. I thank the James and Edna Clark Scholarship, The Canterbury Botanical Society and the Ms E.L Hellaby Indigenous Grasslands Research Trust for funding my research. Thank you to my friends in particular: Archie MacFarlane, Jennifer Low, Andrew Davies and the Gekus erykus crew for their continued support in interesting times. Finally I would like to thank and honour the memory of my valiant Fiat Tipo A.K.A: Giuseppe, The Mighty Tipo and The Starship Enterprise who gave his life for this project after sustaining catastrophic injuries while in the field. 3 TABLE OF CONTENTS ABSTRACT ................................................................................................................... 6 Chapter One: .................................................................................................................. 7 General Introduction .................................................................................................. 7 Chapter Two ................................................................................................................. 15 Molecular phylogeny and biogeography of New Zealand’s Senecio (Senecioneae: Asteraceae). .................................................................................................................. 15 2.1. Abstract ................................................................................................................. 16 2.2. Introduction ........................................................................................................... 17 2.3. Material and Methods ........................................................................................... 20 2.4. Results ................................................................................................................... 23 2.4. Discussion ............................................................................................................. 27 Chapter Two: Tables and Figures ................................................................................ 33 Table 2.1. ..................................................................................................................... 33 Figure 2.1. .................................................................................................................... 34 Figure 2.2. .................................................................................................................... 35 Figure 2.3.. ................................................................................................................... 36 Figure 2.4. .................................................................................................................... 37 Chapter Three ........................................................................................................... 38 Phylogenetic effects on enemy release and biotic resistance are minor and inconsistent compared with strong habitat and plant effects. .................................. 38 3.1. Abstract ............................................................................................................. 39 3.2. Introduction ....................................................................................................... 40 3.3. Methods............................................................................................................. 44 3.4. Results ............................................................................................................... 48 3.5. Discussion ......................................................................................................... 53 Chapter 3: Tables and Figures ................................................................................. 59 Table 3.1. ................................................................................................................. 59 Table 3.2. ................................................................................................................. 60 Table 3.3. ................................................................................................................. 60 Table 3.4. ................................................................................................................. 61 Table 3.5. ................................................................................................................. 61 Table 3.6. ................................................................................................................. 67 Table 3.7. ................................................................................................................. 69 Table 3.8. ................................................................................................................. 70 Table 3.9. ................................................................................................................. 72 Table 3.10. ............................................................................................................... 78 4 Figure 3.1. ................................................................................................................ 80 Chapter Four ........................................................................................................ 81 4.1. General Discussion ....................................................................................... 81 Bibliography: ................................................................................................... 85 Appendix I ................................................................................................... 96 Appendix II ............................................................................................ 108 5 Abstract Senecio is one of the largest genera in the Asteraceae family with 28 Senecio species in New Zealand and over 1200 species worldwide. Native Senecio in the Canterbury region are typically naturally uncommon and exhibit extreme fluctuations in population size. Contrary to native Senecio, exotic Senecio in the Canterbury region are thriving. Why some exotic species thrive in a novel environment while native species decline has been an area of intense study since the era of Darwin. However, despite extensive study, we are still unsure about the underlying mechanisms of this phenomenon. This thesis looks at several hypotheses that have been proposed to explain differences in success between native and exotic species including four that have been frequently mentioned in the literature: phylogenetics, natural enemy release and biotic resistance, allopolyploidy and habitat modification. In order to determine if phylogenetic relatedness influences the abundance and distribution of Senecio species in Canterbury, DNA phylogenies of New Zealand’s Senecio were constructed using nuclear (ITS, ETS) and plastid (trnL, trnL-F and psbA-trnH) DNA sequences. The resulting cladograms were used to determine the areas of origin of New Zealand’s Senecio lineages, the identity of their closest relatives and lineages and species that are of allopolyploid origin. The data provided by the phylogenetic analyses was to provide context for analyses of ecological data of 86 native and exotic Senecio populations from the Canterbury region. My results indicate that phylogenetic relatedness is a poor predictor of the amount of folivory experienced by Senecio, although some natural enemies of native and exotic Senecio displayed a positive preference for Senecio depending on their clade. The strongest effects on Senecio and the occurrences of their natural enemies came from the surrounding land use which influenced the amount of folivory and the abundances of natural enemies on Senecio. Enemy release and biotic resistance were land use specific within Canterbury and by themselves cannot explain the variance in folivory when applied to a landscape scale. According to my results, the biggest factor influencing Senecio folivory, abundance and distribution in the Canterbury region is change in the surrounding land use. 6 Chapter One: General Introduction As primary producers, plants form the foundations of many ecosystems because of the ecosystem services and functions that they provide such as nutrient