Native Community Responses to Alien Grass Invasion: Role of Landscape
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University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2014 Native community responses to alien grass invasion: role of landscape and native plant functional traits in mediating invader impacts Ben William Gooden University of Wollongong Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] NATIVE COMMUNITY RESPONSES TO ALIEN GRASS INVASION: ROLE OF LANDSCAPE AND NATIVE PLANT FUNCTIONAL TRAITS IN MEDIATING INVADER IMPACTS A thesis submitted in fulfilment of the requirements for the award of the degree DOCTOR OF PHILOSOPHY From UNIVERSITY OF WOLLONGONG By Ben William Gooden BScAdv (Hons) SCHOOL OF BIOLOGICAL SCIENCES July 2014 CERTIFICATION I, Ben William Gooden, declare that this thesis, submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy, in the School of Biological Sciences, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. Ben William Gooden 28th July 2014 i STATEMENT OF CANDIDATE CONTRIBUTION The four data chapters (i.e. Chapters 2, 3, 4 & 5) presented in this thesis have been prepared as manuscripts in collaboration with my supervisers Kristine French and Sharon Robinson. These chapters have been written as the following journal articles: Chapter 2 – Gooden, B. & French, K. (2014) Non-interactive effects of plant invasion and landscape modification on native communities. Diversity and Distributions, 9, 626-639. Chapter 3 – Gooden, B. & French, K. (2014) Impacts of alien grass invasion in coastal seed banks vary amongst native growth forms and dispersal strategies. Biological Conservation, 171, 114–126. Chapter 4 – Gooden, B., French, K. & Robinson, S. A. (2014) Alien grass disrupts reproduction and post-settlement recruitment of co-occurring native vegetation: a mechanism for diversity decline in invaded forest? Plant Ecology, 215, 567-580. Chapter 5 – Gooden, B. & French, K. (in press) Impacts of alien plant invasion on native plant communities are mediated by functional identity of resident species, not resource availability. Oikos 10.1111/oik.01724 As the primary supervisor, I, Professor Kristine French, declare that the greater part of the work in each article listed is attributed to the candidate, Ben William Gooden. In each of the above manuscripts, Ben led conceptual development, study design and was primarily responsible for data collection, data analysis and data interpretation. The first draft of each manuscript was writtenby the candidate and Ben was then responsible for responding to the editing suggestions of his co-authors. The co-authors, Professor Kris French and Professor Sharon Robinson, were responsible for assisting with study design, interpreting data and editing the manuscripts where necessary. Ben has been solely responsible for submitting each manuscript for publication to the relevant journals, and he has been in charge of responding to reviewers’ comments. Ben William Gooden Professor Kristine French PhD Candidate Principal Supervisor 28 July 2014 28 July 2014 ii PUBLICATIONS & PRESENTATIONS In addition to the published manuscripts listed above, during the course of my PhD I have published one book chapter, two journal articles and presented data from this thesis at national and international conferences. I also facilitated three workshops and was invited to deliver a talk on invasive plant ecology and management at an international meeting on bridging theory and practice in weed research. A summary of this acitivity is provided below. Publications French, K., Gooden, B. & Mason, T. J. (2014) Invasion by woody shrubs and trees. In Prins, H. and Gordon, I. (Eds) When Continents Collide: Biological Invasions and Ecosystem Theory. Cambridge University Press, UK. Gooden, B., French, K., Turner, P. & Downey, P. O. (2009) Impact threshold for an alien plant invader, Lantana camara L., on native plant communities. Biological Conservation 142, 2631–2641 Gooden, B., French, K., & Turner, P. 2009. Invasion and management of a woody plant, Lantana camara L., alters vegetation diversity within wet sclerophyll forest in southeastern Australia. Forest Ecology and Management 257, 960–967 Conference presentations Gooden, B. & French, K. (2013) Does alien grass invasion affect recruitment dynamics and reproduction of resident native plants? EcoTas13 – 5th joint conference of the Ecological Society of Australia and the New Zealand Ecological Society. Gooden, B. & French, K. (2012) Alien turfgrass impacts on coastal seed banks: implications for community resilience. Ecological Society of Australia Conference, Melbourne. Gooden, B. & French, K. (2011) Impacts of an exotic grass on native coastal plant communities. Ecological Society of Australia Conference, Hobart. Gooden, B. & French, K. (2011) Impacts of an alien grass on native coastal plant communities. International Congress for Conservation Biology, Auckland. Gooden, B. (2011) Impacts of an alien grass in an endangered coastal forest. Postgraduate Student Conference, University of Wollongong. iii Gooden, B. & French, K. (2010) Classical Braun-Blanquet cover-abundance index: assessing its utility in plant surveys. Ecological Society of Australia Conference, Canberra. Gooden, B., French, K., Turner, P. & Downey, P. O. (2010). Invader impact thresholds on native plant communities. Ecological Society of Australia Conference, Canberra. Gooden, B. (2010) Impacts of alien grasses on native communities: a search for patterns and mechanisms. Postgraduate Student Conference, University of Wollongong. Gooden, B., French, K., Turner, P. & Downey, P. O. (2007) Verifying native plant species at risk from lantana. The 14th Biennial NSW Weeds Conference, Wollongong. Invited presentations Gooden, B. & French, K. (2013) Invasion and management of weeds in Australia: emergent ecological knowledge and future research needs. Living with, living without weeds: bridging theory and practice, Australian Centre for Cultural Environmental Research, Wollongong. Facilitated workshops Gruber, M. & Gooden, B. (2013) Invasive species in a changing world: are we asking the right questions? EcoTas13 – 5th joint conference of the Ecological Society of Australia and the New Zealand Ecological Society. Gooden, B. & Cherry, H. (2012) Ecological Management of Invasive Species: Bridging theory and practice. Ecological Society of Australia Conference, Melbourne. Gooden, B. & Cherry, H. (2012) Ecology of Invasive Species Management – bridging the gap between research and practice. 18th Australasian Weeds Conference, Melbourne. Herbarium collection As part of my research, I also collected, identified, preserved and catalogued over 600 plant specimens, which I am in the process of lodging as voucher specimens at the Janet Cosh Herbarium, University of Wollongong. iv TABLE OF CONTENTS CERTIFICATION ........................................................................................................... i STATEMENT OF CANDIDATE CONTRIBUTION ................................................. ii PUBLICATIONS & PRESENTATIONS .................................................................... iii TABLE OF CONTENTS ................................................................................................ v LIST OF TABLES ......................................................................................................... ix LIST OF FIGURES ..................................................................................................... xiv LIST OF APPENDICES ............................................................................................. xix ABSTRACT .................................................................................................................. xxi ACKNOWLEDGEMENTS ........................................................................................ xxv Chapter 1: GENERAL INTRODUCTION .................................................................. 1 1.1. Alien plant invaders as agents of global environmental change ........................................ 1 1.1.1. Mechanistic definitions of alien plant invasion .......................................................... 4 1.1.2. Drivers of alien plant invasion .................................................................................... 6 1.2. Impacts of alien plant invasion on native plant communities: patterns and mechanisms 14 1.2.1. Impacts on genetic diversity, populations and recruitment dynamics of native plants ............................................................................................................................................ 15 1.2.2. Impacts on community diversity, composition and ecosystem processes ................ 18 1.2.3. Mediators of invasive plant impacts on native communities .................................... 20 1.2.4. Global research limitations and future focus ............................................................ 22 1.3. Thesis outline ................................................................................................................... 23 1.3.1. Model species: Stenotaphrum secundatum (Walter) Kuntze .................................... 24 1.3.2. Model system: Swamp oak floodplain forest ............................................................ 27 1.3.3. Thesis structure