The University of Notre Dame Australia ResearchOnline@ND Theses 2020 Causes of Variable Jarrah (Eucalyptus Marginata) and Marri (Corymbia Calophylla) Seedling Density at Establishment Following Bauxite Mining in the Northern Jarrah Forest of Western Australia Tai White-Toney The University of Notre Dame Australia Follow this and additional works at: https://researchonline.nd.edu.au/theses Part of the Arts and Humanities Commons COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING The material in this communication may be subject to copyright under the Act. Any further copying or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Publication Details White-Toney, T. (2020). Causes of Variable Jarrah (Eucalyptus Marginata) and Marri (Corymbia Calophylla) Seedling Density at Establishment Following Bauxite Mining in the Northern Jarrah Forest of Western Australia (Doctor of Philosophy (College of Arts and Science)). University of Notre Dame Australia. https://researchonline.nd.edu.au/theses/262 This dissertation/thesis is brought to you by ResearchOnline@ND. It has been accepted for inclusion in Theses by an authorized administrator of ResearchOnline@ND. For more information, please contact [email protected]. Running head: JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING Causes of variable jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) seedling density at establishment following bauxite mining in the Northern Jarrah Forest of Western Australia Tai White-Toney Submitted in fulfilment of the requirements for a Doctor of Philosophy School of Arts and Sciences, Fremantle Campus January 2020 JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING ii Declaration of Authorship To the best of the candidate’s knowledge, this thesis contains no material previously published by another person, except where due acknowledgement has been made. This thesis is the candidate’s own work and contains no material which has been accepted for the award of any other degree or diploma in any institution. Tai White-Toney DATE JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING iii Abstract Seedling densities at establishment of jarrah (Eucalyptus marginata D. Don ex Sm.) and marri (Corymbia calophylla (Lindl). K. D. Hill & L. A. S. Johnson) following bauxite mining in the Northern Jarrah Forest of south-western Australia are variable and few factors explored during 40 years of field studies have explained this variability. This study explored establishment within the framework of limitation due to amount of seed supply and number of suitable microsites for establishment. First, relationships were identified between seedling establishment densities on 654 mine sites restored between 1998 and 2017 and restoration practices (seed and fertiliser application rates), climate conditions (rainfall evenness and seasonal air temperatures) and seed supply (measured as proportion of forest perimeter). Then, canopy-stored seed as a seed source on restoration sites, and its influence on seedling densities, was investigated. Mean (± SE) jarrah seedfall in the first 12.7 m of the forest edges was 10,000 ± 2,624 seeds/ha/year. The variable, but potentially high, jarrah seedfall within 12.7 m of forest edge is an important seed source influencing jarrah seedling densities on restoration sites, but there was very low presence of marri seed in both forest and restoration sites. Last, three complementary field trials were implemented to investigate the importance of microsite characteristics on jarrah and marri seedling establishment in the restoration system. Seedling survival to establishment was high, 83.9–89.2% for jarrah and 93.8–96.8% marri, and survival was not related to microtopography generated by soil ripping or substrate type. However, seedling density was highest in furrows for both species, most likely because of seed movement during surface water run-off. Also, marri density at establishment increased with sulphur and organic carbon and decreased with soil conductivity. Net seed supply of jarrah and marri over a restoration site (including both canopy-stored and sown seed) is variable, and supply, rather than microsite characteristics, is the most likely limitation to seedling establishment. JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING iv Acknowledgements In some ways, this acknowledgements section has been the hardest part of this thesis to write. I find myself at the conclusion of one extraordinary journey and simultaneously on the precipice of a new one. I have thought numerous times about the confluence of events that have brought me to this place, and indeed, gratitude is the primary sentiment I feel and most wish to convey. Very first, thank you to Dylan Korczynskyj for taking a Skype call from a young and eager American girl, for taking that first gamble on me and for betting on me every day since. What I’ve learned from you goes far beyond, but importantly has included, good ecology. Thank you for sharing with me your family and the University of Notre Dame Australia academic community. Andrew Grigg, you and Alcoa welcomed me warmly from the start, provided unconditional support for this project through funding, industry knowledge and help from the very best people (‘rock’ stars, in my view). Your knowledge has been indispensable, and you have taught me that a good research project is never really finished (not even this one). Max Bulsara (Notre Dame), thank you for your genuine, thoughtful and continuous support of my learning, and also for providing me with well-timed and crucial boosts to morale. I can truly say running Generalised Linear Models is my new favourite pastime, thanks to you. Importantly, as I was privileged to spend such a large portion of my research time in the Northern Jarrah Forest, I would like to acknowledge the Traditional Owners and custodians of the region—past, present and emerging: The Pindjarup people of the Noongar nation. Thank you for sharing your land with me. My long hours in the field were mostly accompanied by true-crime podcasts and march flies, but I must absolutely thank my many vastly under-appreciated field helpers; most notably ‘the Cams’ (Cam Richardson and Cam Blackburn) of Alcoa. Cams, thanks for the long hours that you’ve both endured with me. Thanks for continuing to help me even after I stole your markers, ignited small fires and mistook door grease for hummus. Special thanks also to JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING v Justine Barker, Rowan Beals, Jenna Blackwell, Randall Heaysman, Chris Johnstone, Greg Mullins and Kylie Walmsley (all Alcoa). Josi Rosa (University of São Paolo), your presence on site and during my commute brought me incredible joy; you constantly make me ‘better’. Tharcila Peixoto (Alcoa), Natasha Mikich, Beatrice Clifford and Eloise Ashton (Notre Dame), thank you for your help with the seed traps. Your enthusiasm helped get me through. Lachlan Warner (Notre Dame), thanks for taking on the germination project, for sharing the long drive with me and for giving me my very own marri seedlings (which did die, but that is not important). Joe Kinal (Department of Biodiversity, Conservation and Attractions), thank you for access to the seed traps. To my friends and colleagues at Murdoch University, University of Western Australia and Kings Park (special mention to Laura Skates and Lauren Svejcar), thank you for taking me under your collective wings and reminding me that what I was experiencing was ‘normal’. Rachel Standish and Joe Fontaine (Murdoch University), thanks for welcoming me to the Terrestrial Ecology Research Group community. Ryan Tangney (Kings Park Science), thank you for proposing the use of X-rays for my jarrah seed (they weren’t small rocks after all). Kate O’Neill (Notre Dame), thank you for sewing hundreds of seed bags for me. To the Notre Dame and University of Portland (UP) study abroad and residences staff (especially Eddie Contreras, Peta Sanderson, Chelsae Currie, Debbie Guy, Oz Taylor and Mez Badsha), each of you has been an incredible cheerleader— thank you for support and patience. To my Cleos kids (UP), all 108 of you, part of this story is yours too. You helped me make field equipment, studied with me into the early hours of the morning and mistakenly diagnosed me with liver failure when I developed a few bruises from carrying seed traps. Being your mum-friend and doing this research full-time was an incredible challenge, but an even more incredible reward. To all of my dear friends in both America and Australia (too many of you to list), you all are so important to me. Thanks for listening, thanks for pushing me, thanks for catching me, thanks for your patience when I JARRAH AND MARRI ESTABLISHMENT AFTER BAUXITE MINING vi didn’t call you back, and thank you for only sometimes making fun of me for petting plants or walking around with seed capsules in my hand. Thanks to my mum cheer squad, Teresa Newell and Gayleen Webb— this last year has been made possible through your friendship and support. To my fellow Notre Dame HDR friends (special mention to Jane Minson, Toni Church and Alex Wallis), you all have inspired me every day and have been incredible travel companions on this journey. Tara Holt (UP), thanks for the crab lab. So much of who I am now is a direct outgrowth of my time with you. I have worn your ring everyday of this process and carry you and your fire with me always. To my Australian families (the Bakers, Dyces and Gannons) thank you for feeding, housing and caring for me. I am so grateful to be your ‘American daughter’ and would not have made it without your incredible hospitality. Thank you for giving me a place to relax and laugh, and even sometimes to do some writing. A very, very special ‘thank you’ to the Dyce family—Dennis, Kay, Emma and Sarah—for opening your home to me for this last year; I am forever grateful to be your D3.