Terrestrial alien ferns (Polypodiophyta): A global assessment of traits associated with invasiveness and their distribution and status in South Africa By Emily Joy Jones Submitted in fulfilment of the requirements for the degree Master of Science in the Faculty of Science at the Nelson Mandela University April 2019 Supervisor: Dr Tineke Kraaij Co-Supervisor: Dr Desika Moodley Declaration I, Emily Joy Jones (216016479), hereby indicate that the dissertation for Master of Science in the Faculty of Science is my own work and that it has not previously been submitted for assessment or completion of any postgraduate qualification to another University or for another qualification. _______________________ 2019-03-11 Emily Joy Jones DATE Official use: In accordance with Rule G4.6.3, 4.6.3 A treatise/dissertation/thesis must be accompanied by a written declaration on the part of the candidate to the effect that it is his/her own work and that it has not previously been submitted for assessment to another University or for another qualification. However, material from publications by the candidate may be embodied in a treatise/dissertation/thesis. i Table of Contents Abstract ...................................................................................................................................... i Acknowledgements ................................................................................................................ iii List of Tables ............................................................................................................................ v List of Figures .......................................................................................................................... vi List of Supplementary Material ........................................................................................... vii Thesis Structure, Research Publications and Conference Contributions ...................... viii CHAPTER 1: General Introduction ...................................................................................... 1 Invasion Biology ................................................................................................................................ 1 Invasiveness, Invasibility and Pathways of Introduction ................................................................ 2 Alien Species Inventories, Risk Analysis and Management ............................................................ 3 Ferns as Invaders .............................................................................................................................. 6 Ferns in South Africa ...................................................................................................................... 8 Thesis Objectives ............................................................................................................................. 10 References ........................................................................................................................................ 11 CHAPTER 2: A Global Assessment of Terrestrial Alien Ferns (Polypodiophyta): Species' Traits as Drivers of Naturalisation and Invasion ................................................. 17 Abstract ............................................................................................................................................ 17 Introduction ..................................................................................................................................... 18 Methods ............................................................................................................................................ 21 Inventory, Geographic Distribution and Family Representation ................................................. 21 Analysis of Traits Influencing Invasiveness .................................................................................. 22 Results .............................................................................................................................................. 25 Inventory, Geographic Distribution and Family Representation ................................................. 25 Traits Influencing Invasiveness ..................................................................................................... 27 Discussion ........................................................................................................................................ 30 Conclusion ....................................................................................................................................... 33 Acknowledgements .......................................................................................................................... 34 References ........................................................................................................................................ 35 Supplementary Materials ............................................................................................................... 40 CHAPTER 3: Terrestrial Alien Ferns (Polypodiophyta) in South Africa: Distribution, Abundance and Habitat Associations .................................................................................. 49 Abstract ............................................................................................................................................ 49 Introduction ..................................................................................................................................... 50 Methods ............................................................................................................................................ 53 ii Study Area ..................................................................................................................................... 53 Species Distribution Database ...................................................................................................... 53 Field Surveys ................................................................................................................................. 54 Abundance and Distribution ......................................................................................................... 55 Invasion status and Prominence ................................................................................................... 56 Habitat Traits Analysis ................................................................................................................. 56 Results .............................................................................................................................................. 57 Abundance and Distribution ......................................................................................................... 57 Prominence ................................................................................................................................... 61 Habitat Associations ..................................................................................................................... 61 Discussion ........................................................................................................................................ 64 Management Implications ............................................................................................................. 67 Acknowledgements ......................................................................................................................... 69 References ........................................................................................................................................ 71 Supplementary Materials ............................................................................................................... 76 CHAPTER 4: Synthesis and Conclusions.......................................................................... 103 Summary of Major Findings ........................................................................................................ 103 Implications for Management ...................................................................................................... 105 Study Limitations .......................................................................................................................... 107 Study Contributions and Recommendations for Future Research .......................................... 107 References ...................................................................................................................................... 111 iii Abstract Globally, invasive alien plants (IAPs) are one of the greatest threats to biodiversity, ecosystems and ecosystem services. The threats posed by IAPs have prompted inventory compilations and screening exercises which aim to understand why some taxa become invasive and others do not. Ferns are a diverse taxon that appear to have a high invasive potential, however ferns have been vastly understudied in the field of invasion biology. This study aimed to establish a basic understanding of terrestrial alien true ferns (Polypodiophyta, hereafter ‘alien ferns’) at both global and national (South African) scales. We developed a global inventory of alien ferns comprising 157 species using published literature and online inventories. Our global inventory indicated that there are significantly more alien fern species than previously estimated (60 species). We used generalised linear models with binomial response