Does intraspecific niche partitioning in a native predator influence its response to an invasion by a toxic prey species?

J Webb, R Shine, Keith Christian

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    The introduced and highly toxic cane toad (Bufo marinus) is rapidly spreading across northern Australia where it may affect populations of large terrestrial vertebrate predators. The ecological impact of cane toads will depend upon the diets, foraging modes and habitat use of native predators, and their feeding responses to cane toads. However, intraspecific niche partitioning may influence the degree of vulnerability of predators to toxic prey, as well as the time course of the impact of alien invaders on native species. We studied the diet of the northern death adder Acanthophis praelongus and their feeding responses to cane toads. In the laboratory, death adders from all size classes and sexes readily consumed frogs and cane toads. Diets of free ranging A. praelongus from the Adelaide River floodplain were more heterogeneous. Juvenile snakes ate mainly frogs (39% of prey items) and small scincid lizards (43%). Both sexes displayed an ontogenetic dietary shift from lizards to mammals, but adult males fed on frogs (49%) and mammals (39%) whereas adult females (which grew larger than males) fed mainly on mammals (91%) and occasionally, frogs (9%). Feeding rates and body condition of adult snakes varied temporally and tracked fluctuations in prey availability. These results suggest that cane toads may negatively affect populations of northern death adders in the Darwin region. However, we predict that different size and sex classes of A. praelongus will experience differential mortality rates over different timescales. The initial invasion of large toads may affect adult males, but juveniles may be unaffected until juvenile toads appear the following year, and major affects on adult female death adders may be delayed until annual rainfall fluctuations reduce the availability of alternative (rodent) prey.
    Original languageEnglish
    Pages (from-to)201-209
    Number of pages9
    JournalAustral Ecology
    Volume30
    Issue number2
    Publication statusPublished - 2005

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    Bufo marinus
    niche partitioning
    toad
    niches
    predator
    predators
    frogs
    frog
    death
    mammals
    toads
    mammal
    snakes
    diet
    snake
    lizards
    gender
    lizard
    dietary shift
    prey availability

    Cite this

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    title = "Does intraspecific niche partitioning in a native predator influence its response to an invasion by a toxic prey species?",
    abstract = "The introduced and highly toxic cane toad (Bufo marinus) is rapidly spreading across northern Australia where it may affect populations of large terrestrial vertebrate predators. The ecological impact of cane toads will depend upon the diets, foraging modes and habitat use of native predators, and their feeding responses to cane toads. However, intraspecific niche partitioning may influence the degree of vulnerability of predators to toxic prey, as well as the time course of the impact of alien invaders on native species. We studied the diet of the northern death adder Acanthophis praelongus and their feeding responses to cane toads. In the laboratory, death adders from all size classes and sexes readily consumed frogs and cane toads. Diets of free ranging A. praelongus from the Adelaide River floodplain were more heterogeneous. Juvenile snakes ate mainly frogs (39{\%} of prey items) and small scincid lizards (43{\%}). Both sexes displayed an ontogenetic dietary shift from lizards to mammals, but adult males fed on frogs (49{\%}) and mammals (39{\%}) whereas adult females (which grew larger than males) fed mainly on mammals (91{\%}) and occasionally, frogs (9{\%}). Feeding rates and body condition of adult snakes varied temporally and tracked fluctuations in prey availability. These results suggest that cane toads may negatively affect populations of northern death adders in the Darwin region. However, we predict that different size and sex classes of A. praelongus will experience differential mortality rates over different timescales. The initial invasion of large toads may affect adult males, but juveniles may be unaffected until juvenile toads appear the following year, and major affects on adult female death adders may be delayed until annual rainfall fluctuations reduce the availability of alternative (rodent) prey.",
    keywords = "biological invasion, niche partitioning, predator-prey interaction, Adelaide River, Australasia, Australia, Eastern Hemisphere, Northern Territory, World, Acanthophis antarcticus, Acanthophis praelongus, Anura, Arundinaria, Bufo marinus, Mammalia, Rodentia, Scincidae, Serpentes, Squamata, Vertebrata",
    author = "J Webb and R Shine and Keith Christian",
    year = "2005",
    language = "English",
    volume = "30",
    pages = "201--209",
    journal = "Australian Journal of Ecology",
    issn = "1442-9985",
    publisher = "Blackwell Publishing",
    number = "2",

    }

    Does intraspecific niche partitioning in a native predator influence its response to an invasion by a toxic prey species? / Webb, J; Shine, R; Christian, Keith.

    In: Austral Ecology, Vol. 30, No. 2, 2005, p. 201-209.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Does intraspecific niche partitioning in a native predator influence its response to an invasion by a toxic prey species?

    AU - Webb, J

    AU - Shine, R

    AU - Christian, Keith

    PY - 2005

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    N2 - The introduced and highly toxic cane toad (Bufo marinus) is rapidly spreading across northern Australia where it may affect populations of large terrestrial vertebrate predators. The ecological impact of cane toads will depend upon the diets, foraging modes and habitat use of native predators, and their feeding responses to cane toads. However, intraspecific niche partitioning may influence the degree of vulnerability of predators to toxic prey, as well as the time course of the impact of alien invaders on native species. We studied the diet of the northern death adder Acanthophis praelongus and their feeding responses to cane toads. In the laboratory, death adders from all size classes and sexes readily consumed frogs and cane toads. Diets of free ranging A. praelongus from the Adelaide River floodplain were more heterogeneous. Juvenile snakes ate mainly frogs (39% of prey items) and small scincid lizards (43%). Both sexes displayed an ontogenetic dietary shift from lizards to mammals, but adult males fed on frogs (49%) and mammals (39%) whereas adult females (which grew larger than males) fed mainly on mammals (91%) and occasionally, frogs (9%). Feeding rates and body condition of adult snakes varied temporally and tracked fluctuations in prey availability. These results suggest that cane toads may negatively affect populations of northern death adders in the Darwin region. However, we predict that different size and sex classes of A. praelongus will experience differential mortality rates over different timescales. The initial invasion of large toads may affect adult males, but juveniles may be unaffected until juvenile toads appear the following year, and major affects on adult female death adders may be delayed until annual rainfall fluctuations reduce the availability of alternative (rodent) prey.

    AB - The introduced and highly toxic cane toad (Bufo marinus) is rapidly spreading across northern Australia where it may affect populations of large terrestrial vertebrate predators. The ecological impact of cane toads will depend upon the diets, foraging modes and habitat use of native predators, and their feeding responses to cane toads. However, intraspecific niche partitioning may influence the degree of vulnerability of predators to toxic prey, as well as the time course of the impact of alien invaders on native species. We studied the diet of the northern death adder Acanthophis praelongus and their feeding responses to cane toads. In the laboratory, death adders from all size classes and sexes readily consumed frogs and cane toads. Diets of free ranging A. praelongus from the Adelaide River floodplain were more heterogeneous. Juvenile snakes ate mainly frogs (39% of prey items) and small scincid lizards (43%). Both sexes displayed an ontogenetic dietary shift from lizards to mammals, but adult males fed on frogs (49%) and mammals (39%) whereas adult females (which grew larger than males) fed mainly on mammals (91%) and occasionally, frogs (9%). Feeding rates and body condition of adult snakes varied temporally and tracked fluctuations in prey availability. These results suggest that cane toads may negatively affect populations of northern death adders in the Darwin region. However, we predict that different size and sex classes of A. praelongus will experience differential mortality rates over different timescales. The initial invasion of large toads may affect adult males, but juveniles may be unaffected until juvenile toads appear the following year, and major affects on adult female death adders may be delayed until annual rainfall fluctuations reduce the availability of alternative (rodent) prey.

    KW - biological invasion

    KW - niche partitioning

    KW - predator-prey interaction

    KW - Adelaide River

    KW - Australasia

    KW - Australia

    KW - Eastern Hemisphere

    KW - Northern Territory

    KW - World

    KW - Acanthophis antarcticus

    KW - Acanthophis praelongus

    KW - Anura

    KW - Arundinaria

    KW - Bufo marinus

    KW - Mammalia

    KW - Rodentia

    KW - Scincidae

    KW - Serpentes

    KW - Squamata

    KW - Vertebrata

    M3 - Article

    VL - 30

    SP - 201

    EP - 209

    JO - Australian Journal of Ecology

    JF - Australian Journal of Ecology

    SN - 1442-9985

    IS - 2

    ER -