Indirect facilitation of a native mesopredator by an invasive species: are cane toads re-shaping tropical riparian communities?

Sean Doody, Christina Castellano, David Rhind, Brian Green

    Research output: Contribution to journalArticle

    22 Citations (Scopus)

    Abstract

    Top predators can suppress mesopredators both by killing them and by motivating changes in their behavior, and there are numerous examples of mesopredator release caused by declines in top predator populations. Demonstrated cases of invasive species triggering such releases among vertebrate trophic linkages (indirect facilitation), however, are rare. The invasive cane toad, Bufo marinus, has caused severe population-level declines in some Australian predators via lethal toxic ingestion. During a longterm study of the direct impacts of cane toads on predatory monitor lizards in tropical Australia, we documented significant, marked increases in annual counts of a mesopredator, the common tree snake (Dendrelaphis punctulatus). Mean snake counts during surveys of 70-km river transects at two sites increased from \1 individual per survey during 2001–2006, to 8–18 per survey in 2007. These increases occurred approximately 3 years following the arrival of cane toads, and 1–3 years after 71–96 % population declines in three species of predatory monitor lizards (Varanus panoptes, V. mertensi, and V. mitchelli). These data suggest a mesopredator release: the dramatic reduction of predatory monitor lizards caused increases in the tree snake by decreasing predation risk. The increases in tree snake counts were not attributable to either abiotic factors, or a trophic subsidy. The severe declines of predatory monitor lizards, coupled with recent evidence of cascading effects on their prey, suggest that cane toads are re-shaping riparian communities in tropical Australia through both direct negative effects and indirect facilitation.
    Original languageEnglish
    Pages (from-to)559-568
    Number of pages10
    JournalBiological Invasions
    Volume15
    DOIs
    Publication statusPublished - 2013

    Fingerprint

    Bufo marinus
    toad
    facilitation
    snake
    invasive species
    lizard
    snakes
    lizards
    predator
    predators
    Varanus
    population decline
    predation risk
    behavior change
    subsidies
    vertebrate
    transect
    vertebrates
    ingestion
    predation

    Cite this

    Doody, Sean ; Castellano, Christina ; Rhind, David ; Green, Brian. / Indirect facilitation of a native mesopredator by an invasive species: are cane toads re-shaping tropical riparian communities?. In: Biological Invasions. 2013 ; Vol. 15. pp. 559-568.
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    Indirect facilitation of a native mesopredator by an invasive species: are cane toads re-shaping tropical riparian communities? / Doody, Sean; Castellano, Christina; Rhind, David; Green, Brian.

    In: Biological Invasions, Vol. 15, 2013, p. 559-568.

    Research output: Contribution to journalArticle

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