Effects of grazing exclusion on plant species richness and phytomass accumulation vary across a regional productivity gradient

Nick L. Schultz, John W. Morgan, Ian Lunt

    Research output: Contribution to journalArticle

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    Abstract

    Question: Does long-term grazing exclusion affect plant species diversity? And does this effect vary with long-term phytomass accumulation across a regional productivity gradient?Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia.Methods: Floristic surveys and phytomass sampling were conducted across a broad-scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life-form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long-term phytomass accumulation were assessed using multiple linear regression analysis.Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 g m'2). Species evenness and life-form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover.Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context-dependent and vary according to gradients of rainfall, soil fertility and tree cover.
    Original languageEnglish
    Pages (from-to)130-142
    Number of pages13
    JournalJournal of Vegetation Science
    Volume22
    Issue number1
    DOIs
    Publication statusPublished - Feb 2011

    Fingerprint

    phytomass
    grazing
    species richness
    species diversity
    productivity
    Victoria (Australia)
    rain
    species evenness
    rainfall
    ecosystems
    ecosystem
    soil nitrogen
    herbivory
    floristics
    soil fertility
    effect
    plant species
    lowlands
    regression analysis
    herbivores

    Cite this

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    title = "Effects of grazing exclusion on plant species richness and phytomass accumulation vary across a regional productivity gradient",
    abstract = "Question: Does long-term grazing exclusion affect plant species diversity? And does this effect vary with long-term phytomass accumulation across a regional productivity gradient?Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia.Methods: Floristic surveys and phytomass sampling were conducted across a broad-scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life-form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long-term phytomass accumulation were assessed using multiple linear regression analysis.Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 g m'2). Species evenness and life-form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover.Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context-dependent and vary according to gradients of rainfall, soil fertility and tree cover.",
    keywords = "Open access version available, Australia, Biodiversity, Ecology, Grazing, Livestock, Plant diversity, Vegetation",
    author = "Schultz, {Nick L.} and Morgan, {John W.} and Ian Lunt",
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    Effects of grazing exclusion on plant species richness and phytomass accumulation vary across a regional productivity gradient. / Schultz, Nick L.; Morgan, John W.; Lunt, Ian.

    In: Journal of Vegetation Science, Vol. 22, No. 1, 02.2011, p. 130-142.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Effects of grazing exclusion on plant species richness and phytomass accumulation vary across a regional productivity gradient

    AU - Schultz, Nick L.

    AU - Morgan, John W.

    AU - Lunt, Ian

    N1 - Imported on 12 Apr 2017 - DigiTool details were: month (773h) = February, 2011; Journal title (773t) = Journal of Vegetation Science. ISSNs: 1100-9233;

    PY - 2011/2

    Y1 - 2011/2

    N2 - Question: Does long-term grazing exclusion affect plant species diversity? And does this effect vary with long-term phytomass accumulation across a regional productivity gradient?Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia.Methods: Floristic surveys and phytomass sampling were conducted across a broad-scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life-form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long-term phytomass accumulation were assessed using multiple linear regression analysis.Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 g m'2). Species evenness and life-form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover.Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context-dependent and vary according to gradients of rainfall, soil fertility and tree cover.

    AB - Question: Does long-term grazing exclusion affect plant species diversity? And does this effect vary with long-term phytomass accumulation across a regional productivity gradient?Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia.Methods: Floristic surveys and phytomass sampling were conducted across a broad-scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life-form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long-term phytomass accumulation were assessed using multiple linear regression analysis.Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 g m'2). Species evenness and life-form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover.Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context-dependent and vary according to gradients of rainfall, soil fertility and tree cover.

    KW - Open access version available

    KW - Australia

    KW - Biodiversity

    KW - Ecology

    KW - Grazing

    KW - Livestock

    KW - Plant diversity

    KW - Vegetation

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    SN - 1100-9233

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    ER -