Human-Imposed, Fine-Grained Patch Burning Explains the Population Stability of a Fire-Sensitive Conifer in a Frequently Burnt Northern Australia Savanna

Clay Trauernicht, Brett P. Murphy, Lynda D. Prior, Michael J. Lawes, David M.J.S. Bowman

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intratropica. C. intratropica commonly forms small, closed-canopy groves that exclude fire and allow recruitment of conspecifics and other fire-sensitive woody plants. C. intratropica groves provide a useful indicator of heterogeneity and fire regime change, but the mechanisms driving the species’ persistence and decline remain poorly understood. We examined the hypothesis that C. intratropica population stability depends upon a regime of frequent, low-intensity fires maintained by Aboriginal management. We combined integral projection models of C. intratropica population behaviour with an environmental state change matrix to examine how vital rates, grove dynamics and the frequency of high- and low-intensity fires contribute to population stability. Closed-canopy C. intratropica groves contributed disproportionately to population growth by promoting recruitment, whereas singleton trees accounted for a larger proportion of adult mortality. Our patch-based population model predicted population declines under current fire frequencies and that the recruitment of new groves plays a critical role in the species’ persistence. Our results also indicated that reducing fire intensity, a key outcome of Aboriginal burning, leads to C. intratropica population persistence even at high fire frequencies. These findings provide insight into the relationship between ecosystem composition and human–fire interactions and the role of fire management in sustaining the mosaics that comprise ‘natural’ systems.

    Original languageEnglish
    Pages (from-to)896-909
    Number of pages14
    JournalEcosystems
    Volume19
    Issue number5
    DOIs
    Publication statusPublished - 1 Aug 2016

    Fingerprint

    savanna
    groves
    conifers
    coniferous tree
    savannas
    Fires
    fire intensity
    fire regime
    woody plants
    Callitris
    canopy
    persistence
    woody plant
    indigenous peoples
    ecosystems
    wildfires
    Ecosystems
    population growth
    demographic statistics
    fire management

    Cite this

    Trauernicht, Clay ; Murphy, Brett P. ; Prior, Lynda D. ; Lawes, Michael J. ; Bowman, David M.J.S. / Human-Imposed, Fine-Grained Patch Burning Explains the Population Stability of a Fire-Sensitive Conifer in a Frequently Burnt Northern Australia Savanna. In: Ecosystems. 2016 ; Vol. 19, No. 5. pp. 896-909.
    @article{bb9ac3d6c29f4ec8a5368e0f4d900a93,
    title = "Human-Imposed, Fine-Grained Patch Burning Explains the Population Stability of a Fire-Sensitive Conifer in a Frequently Burnt Northern Australia Savanna",
    abstract = "Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intratropica. C. intratropica commonly forms small, closed-canopy groves that exclude fire and allow recruitment of conspecifics and other fire-sensitive woody plants. C. intratropica groves provide a useful indicator of heterogeneity and fire regime change, but the mechanisms driving the species’ persistence and decline remain poorly understood. We examined the hypothesis that C. intratropica population stability depends upon a regime of frequent, low-intensity fires maintained by Aboriginal management. We combined integral projection models of C. intratropica population behaviour with an environmental state change matrix to examine how vital rates, grove dynamics and the frequency of high- and low-intensity fires contribute to population stability. Closed-canopy C. intratropica groves contributed disproportionately to population growth by promoting recruitment, whereas singleton trees accounted for a larger proportion of adult mortality. Our patch-based population model predicted population declines under current fire frequencies and that the recruitment of new groves plays a critical role in the species’ persistence. Our results also indicated that reducing fire intensity, a key outcome of Aboriginal burning, leads to C. intratropica population persistence even at high fire frequencies. These findings provide insight into the relationship between ecosystem composition and human–fire interactions and the role of fire management in sustaining the mosaics that comprise ‘natural’ systems.",
    keywords = "Anthropogenic disturbance, Fire management, Integral projection model (IPM), Patch mosaic burning, Population dynamics, Tropical savanna",
    author = "Clay Trauernicht and Murphy, {Brett P.} and Prior, {Lynda D.} and Lawes, {Michael J.} and Bowman, {David M.J.S.}",
    year = "2016",
    month = "8",
    day = "1",
    doi = "10.1007/s10021-016-9973-2",
    language = "English",
    volume = "19",
    pages = "896--909",
    journal = "Ecosystems",
    issn = "1432-9840",
    publisher = "Springer",
    number = "5",

    }

    Human-Imposed, Fine-Grained Patch Burning Explains the Population Stability of a Fire-Sensitive Conifer in a Frequently Burnt Northern Australia Savanna. / Trauernicht, Clay; Murphy, Brett P.; Prior, Lynda D.; Lawes, Michael J.; Bowman, David M.J.S.

    In: Ecosystems, Vol. 19, No. 5, 01.08.2016, p. 896-909.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Human-Imposed, Fine-Grained Patch Burning Explains the Population Stability of a Fire-Sensitive Conifer in a Frequently Burnt Northern Australia Savanna

    AU - Trauernicht, Clay

    AU - Murphy, Brett P.

    AU - Prior, Lynda D.

    AU - Lawes, Michael J.

    AU - Bowman, David M.J.S.

    PY - 2016/8/1

    Y1 - 2016/8/1

    N2 - Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intratropica. C. intratropica commonly forms small, closed-canopy groves that exclude fire and allow recruitment of conspecifics and other fire-sensitive woody plants. C. intratropica groves provide a useful indicator of heterogeneity and fire regime change, but the mechanisms driving the species’ persistence and decline remain poorly understood. We examined the hypothesis that C. intratropica population stability depends upon a regime of frequent, low-intensity fires maintained by Aboriginal management. We combined integral projection models of C. intratropica population behaviour with an environmental state change matrix to examine how vital rates, grove dynamics and the frequency of high- and low-intensity fires contribute to population stability. Closed-canopy C. intratropica groves contributed disproportionately to population growth by promoting recruitment, whereas singleton trees accounted for a larger proportion of adult mortality. Our patch-based population model predicted population declines under current fire frequencies and that the recruitment of new groves plays a critical role in the species’ persistence. Our results also indicated that reducing fire intensity, a key outcome of Aboriginal burning, leads to C. intratropica population persistence even at high fire frequencies. These findings provide insight into the relationship between ecosystem composition and human–fire interactions and the role of fire management in sustaining the mosaics that comprise ‘natural’ systems.

    AB - Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intratropica. C. intratropica commonly forms small, closed-canopy groves that exclude fire and allow recruitment of conspecifics and other fire-sensitive woody plants. C. intratropica groves provide a useful indicator of heterogeneity and fire regime change, but the mechanisms driving the species’ persistence and decline remain poorly understood. We examined the hypothesis that C. intratropica population stability depends upon a regime of frequent, low-intensity fires maintained by Aboriginal management. We combined integral projection models of C. intratropica population behaviour with an environmental state change matrix to examine how vital rates, grove dynamics and the frequency of high- and low-intensity fires contribute to population stability. Closed-canopy C. intratropica groves contributed disproportionately to population growth by promoting recruitment, whereas singleton trees accounted for a larger proportion of adult mortality. Our patch-based population model predicted population declines under current fire frequencies and that the recruitment of new groves plays a critical role in the species’ persistence. Our results also indicated that reducing fire intensity, a key outcome of Aboriginal burning, leads to C. intratropica population persistence even at high fire frequencies. These findings provide insight into the relationship between ecosystem composition and human–fire interactions and the role of fire management in sustaining the mosaics that comprise ‘natural’ systems.

    KW - Anthropogenic disturbance

    KW - Fire management

    KW - Integral projection model (IPM)

    KW - Patch mosaic burning

    KW - Population dynamics

    KW - Tropical savanna

    UR - http://www.scopus.com/inward/record.url?scp=84962255720&partnerID=8YFLogxK

    U2 - 10.1007/s10021-016-9973-2

    DO - 10.1007/s10021-016-9973-2

    M3 - Article

    VL - 19

    SP - 896

    EP - 909

    JO - Ecosystems

    JF - Ecosystems

    SN - 1432-9840

    IS - 5

    ER -