Local adaptation and genetic variation in south-western Australian forest trees: implications for restoration

Eleanor O'Brien

    Research output: ThesisDoctoral Thesis

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    Abstract

    [Truncated abstract] Spatial structuring of genetic variation is commonly observed in plant species due to limited dispersal and local adaptation. Intraspecific genetic variation has significant implications for ecological restoration because the source of seed or plants influences patterns of gene flow, and may affect performance if there is adaptive divergence among source populations. This study assessed quantitative trait variation, local adaptation and molecular variation within three common, widespread, long-lived forest tree species from south-western Australia to understand the distribution of intraspecific genetic variation and predict the consequences of seed transfer for restoration. The geographic distribution of quantitative trait variation of jarrah Eucalyptus marginata was assessed through measurement of 15-year-old trees grown in a provenance trial. Survival of trees from the northern jarrah forest was significantly higher than that of trees from southern jarrah forest provenances, where mean annual rainfall is much higher, but stem diameter at breast height (d.b.h.) of southern jarrah forest trees was greater, implying faster growth. D.b.h. of trees from within the northern jarrah forest also exhibited a positive relationship with mean annual rainfall, with maximum d.b.h. observed in trees from provenances in the high rainfall zone. These patterns may reflect selection for faster growth under high rainfall conditions or environmentally-induced parental effects. The percentage of trees bearing buds and flowers varied among latitudinal divisions. ... Neither genetic variation within nor among populations of any species could explain variation of emergence and establishment in reciprocal transplant trials. Collectively, the findings of this study suggest structuring of genetic variation in these species at a broad, rather than a very local, scale. This is expected for widespread, long-lived species, where extensive gene flow and temporal variation are likely to favour high within, relative to among, population genetic variation. However, there is evidence that the source of seed may have a significant influence on the success of restoration of these species, whether as a result of genetic variation among populations or due to other factors affecting seed quality. These results highlight the importance of integrating studies of molecular and adaptive trait variation when seeking to understand the causes and consequences of genetic variation within plant species and contribute to the development of seed sourcing practices for improved restoration success.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Publication statusUnpublished - 2007

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    Eucalyptus marginata
    forest trees
    genetic variation
    provenance
    rain
    quantitative traits
    tree and stand measurements
    gene flow
    seeds
    adaptive radiation
    ecological restoration
    seed quality
    seed development
    South Australia
    Western Australia
    temporal variation
    population genetics
    geographical distribution
    buds
    flowers

    Cite this

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    title = "Local adaptation and genetic variation in south-western Australian forest trees: implications for restoration",
    abstract = "[Truncated abstract] Spatial structuring of genetic variation is commonly observed in plant species due to limited dispersal and local adaptation. Intraspecific genetic variation has significant implications for ecological restoration because the source of seed or plants influences patterns of gene flow, and may affect performance if there is adaptive divergence among source populations. This study assessed quantitative trait variation, local adaptation and molecular variation within three common, widespread, long-lived forest tree species from south-western Australia to understand the distribution of intraspecific genetic variation and predict the consequences of seed transfer for restoration. The geographic distribution of quantitative trait variation of jarrah Eucalyptus marginata was assessed through measurement of 15-year-old trees grown in a provenance trial. Survival of trees from the northern jarrah forest was significantly higher than that of trees from southern jarrah forest provenances, where mean annual rainfall is much higher, but stem diameter at breast height (d.b.h.) of southern jarrah forest trees was greater, implying faster growth. D.b.h. of trees from within the northern jarrah forest also exhibited a positive relationship with mean annual rainfall, with maximum d.b.h. observed in trees from provenances in the high rainfall zone. These patterns may reflect selection for faster growth under high rainfall conditions or environmentally-induced parental effects. The percentage of trees bearing buds and flowers varied among latitudinal divisions. ... Neither genetic variation within nor among populations of any species could explain variation of emergence and establishment in reciprocal transplant trials. Collectively, the findings of this study suggest structuring of genetic variation in these species at a broad, rather than a very local, scale. This is expected for widespread, long-lived species, where extensive gene flow and temporal variation are likely to favour high within, relative to among, population genetic variation. However, there is evidence that the source of seed may have a significant influence on the success of restoration of these species, whether as a result of genetic variation among populations or due to other factors affecting seed quality. These results highlight the importance of integrating studies of molecular and adaptive trait variation when seeking to understand the causes and consequences of genetic variation within plant species and contribute to the development of seed sourcing practices for improved restoration success.",
    keywords = "Forest reproduction, Western Australia, South-West, Restoration ecology, Forest genetics, Forest management, Trees, Genetics, Local adaptation, Forest trees, Population genetics, Restoration",
    author = "Eleanor O'Brien",
    year = "2007",
    language = "English",

    }

    TY - THES

    T1 - Local adaptation and genetic variation in south-western Australian forest trees: implications for restoration

    AU - O'Brien, Eleanor

    PY - 2007

    Y1 - 2007

    N2 - [Truncated abstract] Spatial structuring of genetic variation is commonly observed in plant species due to limited dispersal and local adaptation. Intraspecific genetic variation has significant implications for ecological restoration because the source of seed or plants influences patterns of gene flow, and may affect performance if there is adaptive divergence among source populations. This study assessed quantitative trait variation, local adaptation and molecular variation within three common, widespread, long-lived forest tree species from south-western Australia to understand the distribution of intraspecific genetic variation and predict the consequences of seed transfer for restoration. The geographic distribution of quantitative trait variation of jarrah Eucalyptus marginata was assessed through measurement of 15-year-old trees grown in a provenance trial. Survival of trees from the northern jarrah forest was significantly higher than that of trees from southern jarrah forest provenances, where mean annual rainfall is much higher, but stem diameter at breast height (d.b.h.) of southern jarrah forest trees was greater, implying faster growth. D.b.h. of trees from within the northern jarrah forest also exhibited a positive relationship with mean annual rainfall, with maximum d.b.h. observed in trees from provenances in the high rainfall zone. These patterns may reflect selection for faster growth under high rainfall conditions or environmentally-induced parental effects. The percentage of trees bearing buds and flowers varied among latitudinal divisions. ... Neither genetic variation within nor among populations of any species could explain variation of emergence and establishment in reciprocal transplant trials. Collectively, the findings of this study suggest structuring of genetic variation in these species at a broad, rather than a very local, scale. This is expected for widespread, long-lived species, where extensive gene flow and temporal variation are likely to favour high within, relative to among, population genetic variation. However, there is evidence that the source of seed may have a significant influence on the success of restoration of these species, whether as a result of genetic variation among populations or due to other factors affecting seed quality. These results highlight the importance of integrating studies of molecular and adaptive trait variation when seeking to understand the causes and consequences of genetic variation within plant species and contribute to the development of seed sourcing practices for improved restoration success.

    AB - [Truncated abstract] Spatial structuring of genetic variation is commonly observed in plant species due to limited dispersal and local adaptation. Intraspecific genetic variation has significant implications for ecological restoration because the source of seed or plants influences patterns of gene flow, and may affect performance if there is adaptive divergence among source populations. This study assessed quantitative trait variation, local adaptation and molecular variation within three common, widespread, long-lived forest tree species from south-western Australia to understand the distribution of intraspecific genetic variation and predict the consequences of seed transfer for restoration. The geographic distribution of quantitative trait variation of jarrah Eucalyptus marginata was assessed through measurement of 15-year-old trees grown in a provenance trial. Survival of trees from the northern jarrah forest was significantly higher than that of trees from southern jarrah forest provenances, where mean annual rainfall is much higher, but stem diameter at breast height (d.b.h.) of southern jarrah forest trees was greater, implying faster growth. D.b.h. of trees from within the northern jarrah forest also exhibited a positive relationship with mean annual rainfall, with maximum d.b.h. observed in trees from provenances in the high rainfall zone. These patterns may reflect selection for faster growth under high rainfall conditions or environmentally-induced parental effects. The percentage of trees bearing buds and flowers varied among latitudinal divisions. ... Neither genetic variation within nor among populations of any species could explain variation of emergence and establishment in reciprocal transplant trials. Collectively, the findings of this study suggest structuring of genetic variation in these species at a broad, rather than a very local, scale. This is expected for widespread, long-lived species, where extensive gene flow and temporal variation are likely to favour high within, relative to among, population genetic variation. However, there is evidence that the source of seed may have a significant influence on the success of restoration of these species, whether as a result of genetic variation among populations or due to other factors affecting seed quality. These results highlight the importance of integrating studies of molecular and adaptive trait variation when seeking to understand the causes and consequences of genetic variation within plant species and contribute to the development of seed sourcing practices for improved restoration success.

    KW - Forest reproduction

    KW - Western Australia

    KW - South-West

    KW - Restoration ecology

    KW - Forest genetics

    KW - Forest management

    KW - Trees

    KW - Genetics

    KW - Local adaptation

    KW - Forest trees

    KW - Population genetics

    KW - Restoration

    M3 - Doctoral Thesis

    ER -