Ecology of the declining Olearia lineata and not-threatened Olearia bullata in human-modified environments and implications for their conservation Olearia lineata population in Gorge Creek, Alexandra. 1 A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science In ECOLOGY at the University of Canterbury By Michelle Teresa Lambert School of Biological Sciences, University of Canterbury, Christchurch, New Zealand 2015 2 Table of Contents Ecology of the declining Olearia lineata and not-threatened Olearia bullata in human- modified environments and implications for their conservation .............................................. 1 Table of Contents ....................................................................................................................... 3 Acknowledgements .................................................................................................................... 6 Abstract ...................................................................................................................................... 7 Chapter 1: Introduction ............................................................................................................. 9 Background .............................................................................................................................. 10 Biodiversity decline and key drivers ................................................................................................. 10 Land-use modification ...................................................................................................................... 10 Biotic exchange- invasion of exotic species ...................................................................................... 11 Interactive effects of land-use change and biotic exchange ............................................................ 12 How species differ in their response to environmental change ....................................................... 13 Biodiversity loss and plant-animal interactions ................................................................................ 13 Land-use change and species invasion in New Zealand ................................................................... 14 Demographics of native species ....................................................................................................... 15 Why study these species? ........................................................................................................ 16 Biology and ecology of Olearia bullata and Olearia lineata ............................................................. 16 Olearia bullata H.D. Wilson & Garn.-Jones 1992 .............................................................................. 17 Olearia lineata (Kirk) Cockayne 1911 ................................................................................................ 18 Importance of Olearia lineata and Olearia bullata ........................................................................... 20 Importance of Olearia bullata and Olearia lineata for Invertebrates ........................................... 21 Importance of Olearia bullata and Olearia lineata for ecosystems .............................................. 22 Importance of Olearia bullata and Olearia lineata for succession ................................................ 22 Aim of Research ....................................................................................................................... 23 Chapter 2: Population Demographics and Community Composition of Olearia lineata and Olearia bullata ......................................................................................................................... 24 Introduction ............................................................................................................................. 25 Methods ................................................................................................................................... 28 Site selection and Sampling .............................................................................................................. 28 Population Demographic Structure of O. lineata and O. bullata ...................................................... 29 Abiotic and Biotic Attributes, and Vegetation Community Composition for O. lineata and O. bullata .......................................................................................................................................................... 30 RECCE plot method- Abiotic Attributes ........................................................................................ 31 3 RECCE plot method- Biotic Attributes and Vegetation Community Composition ........................ 31 Data analysis ..................................................................................................................................... 31 Population Demographic Structure of O. lineata and O. bullata ...................................................... 32 Abiotic and Biotic Attributes, and Vegetation Community Composition for O. lineata and O.bullata .......................................................................................................................................................... 32 Results ...................................................................................................................................... 33 Population Demographic Structure of O. lineata and O. bullata ...................................................... 33 Abiotic and Biotic Attributes, and Vegetation Community Composition for O. lineata and O.bullata .......................................................................................................................................................... 35 Abiotic attributes: ......................................................................................................................... 35 Biotic attributes: ........................................................................................................................... 36 Vegetation Community Composition of O. lineata and O. bullata sites ........................................... 37 Discussion................................................................................................................................. 41 Community attributes- abiotic, biotic and species composition characteristics .............................. 41 Population Demographics of O. lineata and O. bullata .................................................................... 43 Chapter 3: ................................................................................................................................. 50 The effect of an invasive species and light availability on O. lineata and O. bullata .............. 50 Introduction ............................................................................................................................. 51 Methods ................................................................................................................................... 54 Germination experiment .................................................................................................................. 55 Preliminary seed germination trial ............................................................................................... 55 Main Germination Experiment ..................................................................................................... 55 Data analysis ................................................................................................................................. 56 Competition experiment ................................................................................................................... 58 Data analysis ................................................................................................................................. 60 Results ...................................................................................................................................... 63 Germination experiment .................................................................................................................. 63 Germination success ..................................................................................................................... 63 Germination over time .................................................................................................................. 64 Competition Experiment ................................................................................................................... 65 Discussion................................................................................................................................. 69 Competitive effects of grass ......................................................................................................... 71 How do exotic grasses invade communities? .............................................................................. 74 Chapter 4- Lepidoptera and host reliance ............................................................................... 76 Introduction ............................................................................................................................. 77 4 Methods ................................................................................................................................... 79 Field sampling ..................................................................................................................................