Reproductive biology of Australian acacias: important mediator of invasiveness?

Authors

  • Michelle R. Gibson,

    Corresponding author
    1. Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
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  • David M. Richardson,

    1. Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
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  • Elizabete Marchante,

    1. Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Apartado 3046, Coimbra 3001-401, Portugal
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  • Hélia Marchante,

    1. Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Apartado 3046, Coimbra 3001-401, Portugal
    2. Centre for Studies of Natural Resources, Environment and Society; Department of Environment, Escola Superior Agrária de Coimbra, Bencanta, Coimbra 3040-316, Portugal
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  • James G. Rodger,

    1. Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu-Natal, P. Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
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  • Graham N. Stone,

    1. Institute of Evolutionary Biology, University of Edinburgh, The King’s Buildings, West Mains Road, Edinburgh EH9 3JT, UK
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  • Margaret Byrne,

    1. Science Division, Department of Environment and Conservation, Locked Bag 104 Bentley Delivery Centre, Bentley, WA 6983, Australia
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  • Andrés Fuentes-Ramírez,

    1. Laboratorio de Invasiones Biológicas (LIB), Facultad de Ciencias Forestales, Universidad de Concepción, Casilla 160-C, Concepción, Chile
    2. Instituto de Ecología y Biodiversidad (IEB), Santiago, Chile
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  • Nicholas George,

    1. School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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  • Carla Harris,

    1. Plant Invasion and Restoration Ecology Laboratory, Department of Biological Sciences, Faculty of Science, Macquarie University, Sydney, NSW 2109, Australia
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  • Steven D. Johnson,

    1. Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu-Natal, P. Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
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  • Johannes J. Le Roux,

    1. Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
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  • Joseph T. Miller,

    1. Centre for Australian National Biodiversity Research, GPO Box 1600, CSIRO Plant Industry, Canberra, ACT 2601, Australia
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  • Daniel J. Murphy,

    1. National Herbarium of Victoria, Royal Botanic Gardens Melbourne, Private Bag 2000, Birdwood Avenue, South Yarra, Vic. 3141, Australia
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  • Anton Pauw,

    1. Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
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  • Matthew N. Prescott,

    1. Department of Zoology, Oxford University, South Parks Road, Oxford OX1 3PS, UK
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  • Elizabeth M. Wandrag,

    1. Bio-Protection Research Centre, Lincoln University, Canterbury 7647, New Zealand
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  • John R. U. Wilson

    1. Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
    2. South African National Biodiversity Institute, Kirstenbosch National Botanical Gardens, Claremont 7735, South Africa
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Michelle R. Gibson, Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Matieland 7602, South Africa.
E-mail: mishka.r.g@gmail.com

Abstract

Aim  Reproductive traits are important mediators of establishment and spread of introduced species, both directly and through interactions with other life-history traits and extrinsic factors. We identify features of the reproductive biology of Australian acacias associated with invasiveness.

Location  Global.

Methods  We reviewed the pollination biology, seed biology and alternative modes of reproduction of Australian acacias using primary literature, online searches and unpublished data. We used comparative analyses incorporating an Acacia phylogeny to test for associations between invasiveness and eight reproductive traits in a group of introduced and invasive (23) and non-invasive (129) species. We also explore the distribution of groups of trait ‘syndromes’ between invasive and non-invasive species.

Results  Reproductive trait data were only available for 126 of 152 introduced species in our data set, representing 23/23 invasive and 103/129 non-invasive species. These data suggest that invasives reach reproductive maturity earlier (10/13 within 2 years vs. 7/26 for non-invasives) and are more commonly able to resprout (11/21 vs. 13/54), although only time to reproductive maturity was significant when phylogenetic relationships were controlled for. Our qualitative survey of the literature suggests that invasive species in general tend to have generalist pollination systems, prolific seed production, efficient seed dispersal and the accumulation of large and persistent seed banks that often have fire-, heat- or disturbance-triggered germination cues.

Conclusions  Invasive species respond quicker to disturbance than non-invasive taxa. Traits found to be significant in our study require more in-depth analysis involving data for a broader array of species given how little is known of the reproductive biology of so many taxa in this species-rich genus. Sets of reproductive traits characteristic of invasive species and a general ability to reproduce effectively in new locations are widespread in Australian acacias. Unless there is substantial evidence to the contrary, care should be taken with all introductions.

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