The effect of disturbance on plant rarity and ecosystem function John Wallace Patykowski B.Env.Sci. (hons) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Deakin University February 2018 1 Preface This thesis is a compilation of my own work. I designed the method for the study under guidance from my supervisors Dr Maria Gibson, Dr Matt Dell and Dr Tricia Wevill. Dr Greg Holland and Professor Andrew Bennett provided floristic data for this project; for all other data, I designed and conducted all fieldwork, and collected and organised all data. I designed and undertook all analysis associated with this research, and wrote and revised all thesis chapters. Each data chapter in the thesis was written as a manuscript for publication; as such, each chapter is self-contained and some repetition occurs among chapters, particularly within methods. Due to Deakin University requirements, all references occur at the end of the thesis, rather than at the conclusion of each chapter. All data chapters have been submitted to scientific journals; two (Chapters 2 and 4) have been accepted, and two are under review. Each manuscript was co-authored by my supervisory panel, as well as others specified below, and they have contributed to the ideas presented in each. Chapter 2: Patykowski J, Holland GJ, Dell M, Wevill T, Callister K, Bennett AF, Gibson M (2018) The effect of prescribed burning on plant rarity in a temperate forest. Ecology and Evolution. DOI: 10.1002/ece3.3771 Chapter 3: Patykowski J, Dell M, Wevill T, Gibson M (2017) When functional diversity is not driven by rare species: a case study in a temperate woodland. Manuscript submitted for publication. Chapter 4: Patykowski J, Dell M, Wevill T, Gibson M (In Press) Rarity and nutrient acquisition relationships before and after prescribed burning in an Australian box-ironbark forest. AoB Plants. Chapter 5: Patykowski J, Dell M, Wevill T, Gibson M (2017) Seasonal physiological patterns among sympatric trees during water-deficit, and implications of climate change. Manuscript submitted for publication. iii Acknowledgements Thank you to my supervisors Dr Maria Gibson, Dr Matt Dell, and Dr Tricia Wevill for their tireless efforts over the past few years. Furthermore, thank you to Professor Andrew Bennett and Dr Shaun Cunningham (deceased), both of whom were on my supervisory panel at various stages and made valuable contributions to the project. I would also like to acknowledge the contributions of Dr Greg Holland, Professor Michael Clarke, and the team involved with the Box-Ironbark Experimental Mosaic Burning Project, who provided pre- and post-fire floristic data for this study. Thank you to all family and friends who contributed their support along the way, in particular my parents, Celine Yap, and all past and present post-graduate students whom I have had the pleasure of working alongside and sharing an office with over the past few years. I also would like to thank the Deakin technical staff, in particular Linda Moon, who always was willing to provide assistance and encouragement. Thank you to all the volunteers and field assistants who contributed to this project along the way. Funding was provided by Deakin University, Deakin University Centre for Integrative Ecology, and generous grants from the Holsworth Wildlife Research Endowment Fund, and the Victorian Environmental Assessment Council. This research was conducted under Department of Environment and Primary Industries Scientific Research Permit No. 10006826. This study also used data collected as part of the Box-Ironbark Experimental Mosaic Burning Project, which was funded by the Australian State Government of Victoria’s Department of Environment, Land, Water and Planning (North West Region and Project Hawkeye), and Parks Victoria. This research was conducted under Department of Sustainability and Environment Scientific Research Permit No. 10005470 (2010), and Department of Environment and Primary Industries Scientific Research Permit No. 10007003 (2013). iv Contents Access to thesis i Candidate declaration ii Preface iii Acknowledgements iv List of tables viii List of figures xi Abstract 1 1. Introduction 4 1.1 Defining plant rarity 5 1.2 The functional role of rare species 6 1.3 The effect of disturbance on rare species 9 1.4 Box-ironbark forests 13 1.4.1 Location, geology, and climate 13 1.4.2 Vegetation 14 1.4.3 Disturbance history 14 1.4.4 Nutrient cycling 16 1.5 Thesis aims and structure 18 2. The effect of prescribed burning on plant rarity 21 in a temperate forest 2.1 Introduction 21 2.2 Materials and methods 24 2.2.1 Study area 24 2.2.2 Experimental prescribed burns 26 2.2.3 Pre- and post-burn floristic surveys 28 2.2.4 Categorising species frequency of occurrence 29 2.2.5 Data analysis 29 2.3 Results 32 2.3.1 Effects of prescribed burns on floristic diversity 32 2.3.2 Effects of prescribed burns on floristic 34 composition 2.3.3 Contribution of species life-form and frequency 40 groups to floristic composition 2.4 Discussion 45 2.5 Supporting information for chapter two 50 v Contents (contd.) 3. When functional diversity is not driven by rare species: 65 a case study in a temperate woodland 3.1 Introduction 65 3.2 Materials and methods 69 3.2.1 Study site 69 3.2.2 Experimental prescribed burns 70 3.2.3 Measuring species rarity 70 3.2.4 Species functional traits 71 3.2.5 Data analysis 73 3.3 Results 76 3.4 Discussion 84 3.4.1 Effect of prescribed burning on functional 84 diversity 3.4.2 Effect of species loss on functional diversity 86 3.4.3 Limitations and considerations 87 3.5 Conclusion 88 3.6 Supporting information for chapter three 89 4. Rarity and nutrient acquisition relationships before and 91 after prescribed burning in an Australian box-ironbark forest 4.1 Introduction 91 4.2 Materials and methods 94 4.2.1 Study area 94 4.2.2 Species frequency data 95 4.2.3 Leaf collections 97 4.2.4 Soil sampling 98 4.2.5 Nutrient concentration 98 4.2.6 Data analysis 99 4.3 Results 100 4.3.1 Uniqueness of leaf nutrient profiles and rarity 100 4.3.2 Nutrient acquisition strategies and leaf 103 nutrient profiles 4.3.3 Soil nutrients and fire 110 4.4 Discussion 113 4.4.1 Uniqueness of leaf nutrient profiles and rarity 113 4.4.2 Nutrient acquisition strategies and leaf 114 nutrient profiles 4.4.3 Soil nutrients and fire 117 4.5 Conclusion 118 4.6 Supporting information for chapter four 119 vi Contents (contd.) 5. Seasonal physiological patterns among sympatric trees 126 during water-deficit and implications of climate change 5.1 Introduction 126 5.2 Methods 129 5.2.1 Study area 129 5.2.2 Quantifying species dominance 132 5.2.3 Tree selection for physiological measurements 132 5.2.4 Physiological measurements 133 5.2.5 Data analysis 134 5.3 Results 136 5.3.1 Photosynthesis 136 5.3.2 Transpiration 139 5.3.3 Instantaneous water-use efficiency 141 5.4 Discussion 143 5.4.1 Patterns among species 144 5.4.2 Interactions under a changing climate 145 5.4.3 Functional insurance and global vegetation shift 146 6. Discussion 149 6.1 Effect of disturbance on plant rarity 149 6.2 Contributions of species to ecosystem function 154 6.3 Managing disturbance for ecosystem functionality 156 6.4 Conclusion 159 7. References 160 8. Authorship statement 216 vii List of tables 2.1 The effect of survey year and burn treatment on 35 the floristic composition of landscapes in a box-ironbark forest. 2.2 The similarity in floristic composition of rare plant 36 species among landscapes assigned to different burn treatments, in 2010 (before prescribed burns), and in 2013 (after burns). 2.3 The contribution of species frequency groups 41 (common, less-common, rare) to the floristic similarity of vegetation within, and dissimilarity among, landscapes surveyed in 2010 and 2013. 2.4 The contribution of rare species in different life-form 43 groups towards floristic similarity of rare species within, and dissimilarity among, landscapes in pre-burn and post-burn surveys. 3.1 Functional dispersion, functional divergence, 77 functional evenness, and functional richness among study plots in a temperate forest in southeastern Australia, with survey year (2010, pre-burn; 2013, post-burn) and prescribed burn treatment as fixed factors. 3.2 Community-weighted mean trait values (maximum 79 height, specific leaf area, leaf nitrogen to phosphorus ratio) among study plots in a temperate forest in southeastern Australia, with survey year (2010, pre-burn; 2013, post-burn) and prescribed burn treatment (unburnt control, autumn burn, spring burn) as fixed factors. 4.1 Leaf nutrient concentrations for box-ironbark species 104 identified as important contributors of sampled nutrients through PCA analysis for senesced leaf nutrient concentration. 4.2 Difference in concentration of nutrients between soil 111 depths and among burn treatments in a box-ironbark forest. viii List of tables (contd.) 5.1 Seasonal weather of the Heathcote region in 131 southeastern Australia. 5.2 Seasonal relationship between light and physiological 137 parameters of trees. S2.1 Permutational analysis of dispersions among plots 50 based on their floristic composition, with year of survey and season of burn as fixed factors. S2.2 Pairwise comparisons of average dispersion distance 51 (distance-to-centroid, calculated by permutational analysis of dispersions) among plots within different treatment groups (survey year, season of prescribed burn). S2.3 Average (± SE) dispersion distance (distance-to-centroid, 52 calculated by permutational analysis of dispersions) among plots within different treatment groups (survey year, season of prescribed burn).