Indigenous harvest, exotic pig predation and local persistence of a long-lived vertebrate

managing a tropical freshwater turtle for sustainability and conservation

Damien Fordham, Arthur Georges, Barry Brook

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    1. Until recently, the northern snake-necked turtle (Chelodina rugosa Ogilby, 1890) provided a seasonal source of protein for indigenous communities in tropical northern Australia. Today, feral pigs (Sus scrofa Linnaeus, 1758) exert a heavy predation pressure on C. rugosa, compromising subsistence harvest rates and threatening local persistence. 2. We investigated the influence of pig predation and harvest (subsistence and commercial) on C. rugosa persistence at discrete water holes using a stage-based matrix population model. Vital rates varied with wet season rainfall, pig predation and harvest. In addition, hatchling survival was density-dependent. 3. We show that field-based estimates of pig-related turtle mortality exceed levels that can be offset by increased hatchling survival, leading to predictions of rapid population decline and certain elimination of affected populations within 50 years. 4. Conversely, in the absence of pigs, compensatory increases in hatchling survival were sufficient to allow an annual harvest of up to 20% of subadult and adult C. rugosa without causing extirpation or substantial population suppression. 5. Synthesis and applications. This demographic modelling shows that periodic local culling of pigs, fencing of wetlands to exclude predators, and hatchling supplementation to offset losses from predation are all viable management strategies for ensuring ongoing turtle harvests. Such demonstrations of the potential resilience of long-lived vertebrates under a properly managed harvest regime is important to convince natural resource agencies that conservation management for long-term viability need not exclude some degree of consumptive use. These findings are broadly relevant to applied ecology, providing important implications for the management of wildlife species subject to competing ecological pressures, such as subsistence and commercial harvesting and predation by invasive species. � 2007 The Authors.
    Original languageEnglish
    Pages (from-to)52-62
    Number of pages11
    JournalJournal of Applied Ecology
    Volume45
    Publication statusPublished - 2008

    Fingerprint

    turtle
    pig
    vertebrate
    persistence
    predation
    sustainability
    subsistence
    culling
    conservation management
    population decline
    snake
    invasive species
    wet season
    harvest
    viability
    natural resource
    wetland
    predator
    mortality
    rainfall

    Cite this

    @article{67c57f07d7a54b6dbee3c86fc863caac,
    title = "Indigenous harvest, exotic pig predation and local persistence of a long-lived vertebrate: managing a tropical freshwater turtle for sustainability and conservation",
    abstract = "1. Until recently, the northern snake-necked turtle (Chelodina rugosa Ogilby, 1890) provided a seasonal source of protein for indigenous communities in tropical northern Australia. Today, feral pigs (Sus scrofa Linnaeus, 1758) exert a heavy predation pressure on C. rugosa, compromising subsistence harvest rates and threatening local persistence. 2. We investigated the influence of pig predation and harvest (subsistence and commercial) on C. rugosa persistence at discrete water holes using a stage-based matrix population model. Vital rates varied with wet season rainfall, pig predation and harvest. In addition, hatchling survival was density-dependent. 3. We show that field-based estimates of pig-related turtle mortality exceed levels that can be offset by increased hatchling survival, leading to predictions of rapid population decline and certain elimination of affected populations within 50 years. 4. Conversely, in the absence of pigs, compensatory increases in hatchling survival were sufficient to allow an annual harvest of up to 20{\%} of subadult and adult C. rugosa without causing extirpation or substantial population suppression. 5. Synthesis and applications. This demographic modelling shows that periodic local culling of pigs, fencing of wetlands to exclude predators, and hatchling supplementation to offset losses from predation are all viable management strategies for ensuring ongoing turtle harvests. Such demonstrations of the potential resilience of long-lived vertebrates under a properly managed harvest regime is important to convince natural resource agencies that conservation management for long-term viability need not exclude some degree of consumptive use. These findings are broadly relevant to applied ecology, providing important implications for the management of wildlife species subject to competing ecological pressures, such as subsistence and commercial harvesting and predation by invasive species. � 2007 The Authors.",
    keywords = "demography, density dependence, freshwater, harvesting, mortality, nature conservation, persistence, pig, population decline, population modeling, population viability analysis, predation, recruitment (population dynamics), species conservation, survival, sustainability, turtle, wildlife management, Australasia, Australia, Chelidae, Chelodina rugosa, Suidae, Sus scrofa, Testudines, Vertebrata",
    author = "Damien Fordham and Arthur Georges and Barry Brook",
    year = "2008",
    language = "English",
    volume = "45",
    pages = "52--62",
    journal = "Journal of Applied Ecology",
    issn = "0021-8901",
    publisher = "Wiley-Blackwell",

    }

    Indigenous harvest, exotic pig predation and local persistence of a long-lived vertebrate : managing a tropical freshwater turtle for sustainability and conservation. / Fordham, Damien; Georges, Arthur; Brook, Barry.

    In: Journal of Applied Ecology, Vol. 45, 2008, p. 52-62.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Indigenous harvest, exotic pig predation and local persistence of a long-lived vertebrate

    T2 - managing a tropical freshwater turtle for sustainability and conservation

    AU - Fordham, Damien

    AU - Georges, Arthur

    AU - Brook, Barry

    PY - 2008

    Y1 - 2008

    N2 - 1. Until recently, the northern snake-necked turtle (Chelodina rugosa Ogilby, 1890) provided a seasonal source of protein for indigenous communities in tropical northern Australia. Today, feral pigs (Sus scrofa Linnaeus, 1758) exert a heavy predation pressure on C. rugosa, compromising subsistence harvest rates and threatening local persistence. 2. We investigated the influence of pig predation and harvest (subsistence and commercial) on C. rugosa persistence at discrete water holes using a stage-based matrix population model. Vital rates varied with wet season rainfall, pig predation and harvest. In addition, hatchling survival was density-dependent. 3. We show that field-based estimates of pig-related turtle mortality exceed levels that can be offset by increased hatchling survival, leading to predictions of rapid population decline and certain elimination of affected populations within 50 years. 4. Conversely, in the absence of pigs, compensatory increases in hatchling survival were sufficient to allow an annual harvest of up to 20% of subadult and adult C. rugosa without causing extirpation or substantial population suppression. 5. Synthesis and applications. This demographic modelling shows that periodic local culling of pigs, fencing of wetlands to exclude predators, and hatchling supplementation to offset losses from predation are all viable management strategies for ensuring ongoing turtle harvests. Such demonstrations of the potential resilience of long-lived vertebrates under a properly managed harvest regime is important to convince natural resource agencies that conservation management for long-term viability need not exclude some degree of consumptive use. These findings are broadly relevant to applied ecology, providing important implications for the management of wildlife species subject to competing ecological pressures, such as subsistence and commercial harvesting and predation by invasive species. � 2007 The Authors.

    AB - 1. Until recently, the northern snake-necked turtle (Chelodina rugosa Ogilby, 1890) provided a seasonal source of protein for indigenous communities in tropical northern Australia. Today, feral pigs (Sus scrofa Linnaeus, 1758) exert a heavy predation pressure on C. rugosa, compromising subsistence harvest rates and threatening local persistence. 2. We investigated the influence of pig predation and harvest (subsistence and commercial) on C. rugosa persistence at discrete water holes using a stage-based matrix population model. Vital rates varied with wet season rainfall, pig predation and harvest. In addition, hatchling survival was density-dependent. 3. We show that field-based estimates of pig-related turtle mortality exceed levels that can be offset by increased hatchling survival, leading to predictions of rapid population decline and certain elimination of affected populations within 50 years. 4. Conversely, in the absence of pigs, compensatory increases in hatchling survival were sufficient to allow an annual harvest of up to 20% of subadult and adult C. rugosa without causing extirpation or substantial population suppression. 5. Synthesis and applications. This demographic modelling shows that periodic local culling of pigs, fencing of wetlands to exclude predators, and hatchling supplementation to offset losses from predation are all viable management strategies for ensuring ongoing turtle harvests. Such demonstrations of the potential resilience of long-lived vertebrates under a properly managed harvest regime is important to convince natural resource agencies that conservation management for long-term viability need not exclude some degree of consumptive use. These findings are broadly relevant to applied ecology, providing important implications for the management of wildlife species subject to competing ecological pressures, such as subsistence and commercial harvesting and predation by invasive species. � 2007 The Authors.

    KW - demography

    KW - density dependence

    KW - freshwater

    KW - harvesting

    KW - mortality

    KW - nature conservation

    KW - persistence

    KW - pig

    KW - population decline

    KW - population modeling

    KW - population viability analysis

    KW - predation

    KW - recruitment (population dynamics)

    KW - species conservation

    KW - survival

    KW - sustainability

    KW - turtle

    KW - wildlife management

    KW - Australasia

    KW - Australia

    KW - Chelidae

    KW - Chelodina rugosa

    KW - Suidae

    KW - Sus scrofa

    KW - Testudines

    KW - Vertebrata

    M3 - Article

    VL - 45

    SP - 52

    EP - 62

    JO - Journal of Applied Ecology

    JF - Journal of Applied Ecology

    SN - 0021-8901

    ER -