Invasive grass affects seed viability of native perennial shrubs in arid woodlands

Kaisha M. Edwards, Christine Schlesinger, Mark K.J. Ooi, Kris French, Ben Gooden

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    It is often assumed that declines in native vegetation associated with alien plant invasion are driven by competition between plants for limited resources. However, invasion can also impact native plants through recruitment limitation mechanisms. We examined the effects of Cenchrus ciliaris L. (buffel grass, an alien pasture species) on the seed viability and germination of two native perennial shrubs (Acacia tetragonophylla and A. victoriae) in arid woodlands of central Australia. Dormancy, germination rate and seed viability were assessed using laboratory-based germination assays on seeds collected from the soil and mature shrubs in: (1) woodland invaded by buffel grass and (2) areas in which buffel grass had been removed and reinvasion prevented for at least 7 years. There was a twofold increase in viability of A. victoriae seeds in buffel grass-removed compared with invaded sites, and a faster germination rate (T50) for A. tetragonophylla in buffel grass-removed sites. Acacia victoriae seed mass was reduced by approximately 25% in invaded areas, associated with decomposed or absent embryos. Invasion may limit native recruitment by reducing the viability and germination rate of native seeds prior to dispersal from parent plants. Reduced seed viability would reduce seed bank accumulation and total available seed for A. victoriae, while slower germination rates would minimise the efficiency by which A. tetragonophylla responds to sporadic rainfall events. Both mechanisms could lead to long term declines in native plant populations. Reduced seed viability would compound interference of buffel grass on recruiting plants.

    Original languageEnglish
    Pages (from-to)1763-1774
    Number of pages12
    JournalBiological Invasions
    Volume21
    Issue number5
    Early online date6 Feb 2019
    DOIs
    Publication statusPublished - 1 May 2019

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    grass seed
    Cenchrus ciliaris
    woodlands
    woodland
    viability
    shrub
    shrubs
    grass
    Victoria (Australia)
    seed
    germination
    seeds
    Acacia
    dormancy
    introduced plants
    seed bank
    buried seeds
    embryo (plant)
    embryo
    pasture

    Cite this

    Edwards, Kaisha M. ; Schlesinger, Christine ; Ooi, Mark K.J. ; French, Kris ; Gooden, Ben. / Invasive grass affects seed viability of native perennial shrubs in arid woodlands. In: Biological Invasions. 2019 ; Vol. 21, No. 5. pp. 1763-1774.
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    abstract = "It is often assumed that declines in native vegetation associated with alien plant invasion are driven by competition between plants for limited resources. However, invasion can also impact native plants through recruitment limitation mechanisms. We examined the effects of Cenchrus ciliaris L. (buffel grass, an alien pasture species) on the seed viability and germination of two native perennial shrubs (Acacia tetragonophylla and A. victoriae) in arid woodlands of central Australia. Dormancy, germination rate and seed viability were assessed using laboratory-based germination assays on seeds collected from the soil and mature shrubs in: (1) woodland invaded by buffel grass and (2) areas in which buffel grass had been removed and reinvasion prevented for at least 7 years. There was a twofold increase in viability of A. victoriae seeds in buffel grass-removed compared with invaded sites, and a faster germination rate (T50) for A. tetragonophylla in buffel grass-removed sites. Acacia victoriae seed mass was reduced by approximately 25{\%} in invaded areas, associated with decomposed or absent embryos. Invasion may limit native recruitment by reducing the viability and germination rate of native seeds prior to dispersal from parent plants. Reduced seed viability would reduce seed bank accumulation and total available seed for A. victoriae, while slower germination rates would minimise the efficiency by which A. tetragonophylla responds to sporadic rainfall events. Both mechanisms could lead to long term declines in native plant populations. Reduced seed viability would compound interference of buffel grass on recruiting plants.",
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    Invasive grass affects seed viability of native perennial shrubs in arid woodlands. / Edwards, Kaisha M.; Schlesinger, Christine; Ooi, Mark K.J.; French, Kris; Gooden, Ben.

    In: Biological Invasions, Vol. 21, No. 5, 01.05.2019, p. 1763-1774.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Invasive grass affects seed viability of native perennial shrubs in arid woodlands

    AU - Edwards, Kaisha M.

    AU - Schlesinger, Christine

    AU - Ooi, Mark K.J.

    AU - French, Kris

    AU - Gooden, Ben

    PY - 2019/5/1

    Y1 - 2019/5/1

    N2 - It is often assumed that declines in native vegetation associated with alien plant invasion are driven by competition between plants for limited resources. However, invasion can also impact native plants through recruitment limitation mechanisms. We examined the effects of Cenchrus ciliaris L. (buffel grass, an alien pasture species) on the seed viability and germination of two native perennial shrubs (Acacia tetragonophylla and A. victoriae) in arid woodlands of central Australia. Dormancy, germination rate and seed viability were assessed using laboratory-based germination assays on seeds collected from the soil and mature shrubs in: (1) woodland invaded by buffel grass and (2) areas in which buffel grass had been removed and reinvasion prevented for at least 7 years. There was a twofold increase in viability of A. victoriae seeds in buffel grass-removed compared with invaded sites, and a faster germination rate (T50) for A. tetragonophylla in buffel grass-removed sites. Acacia victoriae seed mass was reduced by approximately 25% in invaded areas, associated with decomposed or absent embryos. Invasion may limit native recruitment by reducing the viability and germination rate of native seeds prior to dispersal from parent plants. Reduced seed viability would reduce seed bank accumulation and total available seed for A. victoriae, while slower germination rates would minimise the efficiency by which A. tetragonophylla responds to sporadic rainfall events. Both mechanisms could lead to long term declines in native plant populations. Reduced seed viability would compound interference of buffel grass on recruiting plants.

    AB - It is often assumed that declines in native vegetation associated with alien plant invasion are driven by competition between plants for limited resources. However, invasion can also impact native plants through recruitment limitation mechanisms. We examined the effects of Cenchrus ciliaris L. (buffel grass, an alien pasture species) on the seed viability and germination of two native perennial shrubs (Acacia tetragonophylla and A. victoriae) in arid woodlands of central Australia. Dormancy, germination rate and seed viability were assessed using laboratory-based germination assays on seeds collected from the soil and mature shrubs in: (1) woodland invaded by buffel grass and (2) areas in which buffel grass had been removed and reinvasion prevented for at least 7 years. There was a twofold increase in viability of A. victoriae seeds in buffel grass-removed compared with invaded sites, and a faster germination rate (T50) for A. tetragonophylla in buffel grass-removed sites. Acacia victoriae seed mass was reduced by approximately 25% in invaded areas, associated with decomposed or absent embryos. Invasion may limit native recruitment by reducing the viability and germination rate of native seeds prior to dispersal from parent plants. Reduced seed viability would reduce seed bank accumulation and total available seed for A. victoriae, while slower germination rates would minimise the efficiency by which A. tetragonophylla responds to sporadic rainfall events. Both mechanisms could lead to long term declines in native plant populations. Reduced seed viability would compound interference of buffel grass on recruiting plants.

    KW - Acacia tetragonophylla

    KW - Acacia victoriae

    KW - Buffel grass

    KW - Cenchrus ciliaris L

    KW - Seed dormancy

    KW - Seed germination

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    U2 - 10.1007/s10530-019-01933-x

    DO - 10.1007/s10530-019-01933-x

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    JF - Biological Invasions

    SN - 1387-3547

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    ER -