Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition

Jarrod KATH, K. Reardon-Smith, Andrew Le Brocque, Fiona DYER, E. Dafny, L. Fritz, M Batterham

    Research output: Contribution to journalArticle

    21 Citations (Scopus)
    19 Downloads (Pure)

    Abstract

    Groundwater decline is widespread, yet its implications for natural systems are poorly understood. Previous research has revealed links between groundwater depth and tree condition; however, critical thresholds which might indicate ecological ‘tipping points’ associated with rapid and potentially irreversible change have been difficult to quantify. This study collated data for two dominant floodplain species, Eucalyptus camaldulensis (river red gum) and E. populnea (poplar box) from 118 sites in eastern Australia where significant groundwater decline has occurred. Boosted regression trees, quantile regression and Threshold Indicator Taxa Analysis were used to investigate the relationship between tree condition and groundwater depth. Distinct non-linear responses were found, with groundwater depth thresholds identified in the range from 12.1 m to 22.6 m for E. camaldulensis and 12.6 m to 26.6 m for E. populnea beyond which canopy condition declined abruptly. Non-linear threshold responses in canopy condition in these species may be linked to rooting depth, with chronic groundwater decline decoupling trees from deep soil moisture resources. The quantification of groundwater depth thresholds is likely to be critical for management aimed at conserving groundwater dependent biodiversity. Identifying thresholds will be important in regions where water extraction and drying climates may contribute to further groundwater decline.
    Original languageEnglish
    Pages (from-to)148-160
    Number of pages13
    JournalGlobal Ecology and Conservation
    Volume2
    DOIs
    Publication statusPublished - 2014

    Fingerprint

    floodplains
    floodplain
    groundwater
    canopy
    Eucalyptus camaldulensis
    Eucalyptus populnea
    rooting
    indicator species
    soil moisture
    drying
    soil water
    biodiversity
    climate
    resource
    river

    Cite this

    KATH, Jarrod ; Reardon-Smith, K. ; Le Brocque, Andrew ; DYER, Fiona ; Dafny, E. ; Fritz, L. ; Batterham, M. / Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition. In: Global Ecology and Conservation. 2014 ; Vol. 2. pp. 148-160.
    @article{2e0c2f7fc78642c4b7e07d60ad193d5e,
    title = "Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition",
    abstract = "Groundwater decline is widespread, yet its implications for natural systems are poorly understood. Previous research has revealed links between groundwater depth and tree condition; however, critical thresholds which might indicate ecological ‘tipping points’ associated with rapid and potentially irreversible change have been difficult to quantify. This study collated data for two dominant floodplain species, Eucalyptus camaldulensis (river red gum) and E. populnea (poplar box) from 118 sites in eastern Australia where significant groundwater decline has occurred. Boosted regression trees, quantile regression and Threshold Indicator Taxa Analysis were used to investigate the relationship between tree condition and groundwater depth. Distinct non-linear responses were found, with groundwater depth thresholds identified in the range from 12.1 m to 22.6 m for E. camaldulensis and 12.6 m to 26.6 m for E. populnea beyond which canopy condition declined abruptly. Non-linear threshold responses in canopy condition in these species may be linked to rooting depth, with chronic groundwater decline decoupling trees from deep soil moisture resources. The quantification of groundwater depth thresholds is likely to be critical for management aimed at conserving groundwater dependent biodiversity. Identifying thresholds will be important in regions where water extraction and drying climates may contribute to further groundwater decline.",
    keywords = "Canopy condition, Dieback, Drought, Tipping point, Ecological threshold, Groundwater dependent ecosystems",
    author = "Jarrod KATH and K. Reardon-Smith and {Le Brocque}, Andrew and Fiona DYER and E. Dafny and L. Fritz and M Batterham",
    year = "2014",
    doi = "10.1016/j.gecco.2014.09.002",
    language = "English",
    volume = "2",
    pages = "148--160",
    journal = "Global Ecology and Conservation",
    issn = "2351-9894",
    publisher = "Elsevier BV",

    }

    Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition. / KATH, Jarrod; Reardon-Smith, K.; Le Brocque, Andrew; DYER, Fiona; Dafny, E.; Fritz, L.; Batterham, M.

    In: Global Ecology and Conservation, Vol. 2, 2014, p. 148-160.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition

    AU - KATH, Jarrod

    AU - Reardon-Smith, K.

    AU - Le Brocque, Andrew

    AU - DYER, Fiona

    AU - Dafny, E.

    AU - Fritz, L.

    AU - Batterham, M

    PY - 2014

    Y1 - 2014

    N2 - Groundwater decline is widespread, yet its implications for natural systems are poorly understood. Previous research has revealed links between groundwater depth and tree condition; however, critical thresholds which might indicate ecological ‘tipping points’ associated with rapid and potentially irreversible change have been difficult to quantify. This study collated data for two dominant floodplain species, Eucalyptus camaldulensis (river red gum) and E. populnea (poplar box) from 118 sites in eastern Australia where significant groundwater decline has occurred. Boosted regression trees, quantile regression and Threshold Indicator Taxa Analysis were used to investigate the relationship between tree condition and groundwater depth. Distinct non-linear responses were found, with groundwater depth thresholds identified in the range from 12.1 m to 22.6 m for E. camaldulensis and 12.6 m to 26.6 m for E. populnea beyond which canopy condition declined abruptly. Non-linear threshold responses in canopy condition in these species may be linked to rooting depth, with chronic groundwater decline decoupling trees from deep soil moisture resources. The quantification of groundwater depth thresholds is likely to be critical for management aimed at conserving groundwater dependent biodiversity. Identifying thresholds will be important in regions where water extraction and drying climates may contribute to further groundwater decline.

    AB - Groundwater decline is widespread, yet its implications for natural systems are poorly understood. Previous research has revealed links between groundwater depth and tree condition; however, critical thresholds which might indicate ecological ‘tipping points’ associated with rapid and potentially irreversible change have been difficult to quantify. This study collated data for two dominant floodplain species, Eucalyptus camaldulensis (river red gum) and E. populnea (poplar box) from 118 sites in eastern Australia where significant groundwater decline has occurred. Boosted regression trees, quantile regression and Threshold Indicator Taxa Analysis were used to investigate the relationship between tree condition and groundwater depth. Distinct non-linear responses were found, with groundwater depth thresholds identified in the range from 12.1 m to 22.6 m for E. camaldulensis and 12.6 m to 26.6 m for E. populnea beyond which canopy condition declined abruptly. Non-linear threshold responses in canopy condition in these species may be linked to rooting depth, with chronic groundwater decline decoupling trees from deep soil moisture resources. The quantification of groundwater depth thresholds is likely to be critical for management aimed at conserving groundwater dependent biodiversity. Identifying thresholds will be important in regions where water extraction and drying climates may contribute to further groundwater decline.

    KW - Canopy condition

    KW - Dieback

    KW - Drought

    KW - Tipping point

    KW - Ecological threshold

    KW - Groundwater dependent ecosystems

    U2 - 10.1016/j.gecco.2014.09.002

    DO - 10.1016/j.gecco.2014.09.002

    M3 - Article

    VL - 2

    SP - 148

    EP - 160

    JO - Global Ecology and Conservation

    JF - Global Ecology and Conservation

    SN - 2351-9894

    ER -