The Ecological Impact of Invasive Cane Toads ( Bufo Marinus ) in Australia

School of Biological Sciences A08, University of Sydney, NSW 2006, Australia.
The Quarterly Review of Biology (Impact Factor: 4.89). 09/2010; 85(3):253-91. DOI: 10.1086/655116
Source: PubMed

ABSTRACT Although invasive species are viewed as major threats to ecosystems worldwide, few such species have been studied in enough detail to identify the pathways, magnitudes, and timescales of their impact on native fauna. One of the most intensively studied invasive taxa in this respect is the cane toad (Bufo marinus), which was introduced to Australia in 1935. A review of these studies suggests that a single pathway-lethal toxic ingestion of toads by frog-eating predators-is the major mechanism of impact, but that the magnitude of impact varies dramatically among predator taxa, as well as through space and time. Populations of large predators (e.g., varanid and scincid lizards, elapid snakes, freshwater crocodiles, and dasyurid marsupials) may be imperilled by toad invasion, but impacts vary spatially even within the same predator species. Some of the taxa severely impacted by toad invasion recover within a few decades, via aversion learning and longer-term adaptive changes. No native species have gone extinct as a result of toad invasion, and many native taxa widely imagined to be at risk are not affected, largely as a result of their physiological ability to tolerate toad toxins (e.g., as found in many birds and rodents), as well as the reluctance of many native anuran-eating predators to consume toads, either innately or as a learned response. Indirect effects of cane toads as mediated through trophic webs are likely as important as direct effects, but they are more difficult to study. Overall, some Australian native species (mostly large predators) have declined due to cane toads; others, especially species formerly consumed by those predators, have benefited. For yet others, effects have been minor or have been mediated indirectly rather than through direct interactions with the invasive toads. Factors that increase a predator's vulnerability to toad invasion include habitat overlap with toads, anurophagy, large body size, inability to develop rapid behavioral aversion to toads as prey items, and physiological vulnerability to bufotoxins as a result of a lack of coevolutionary history of exposure to other bufonid taxa.

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Available from: Richard Shine, Sep 29, 2015
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    • "In the case of anuran amphibians, the two most widespread taxa (the American Bullfrog Lithobates catesbeiana [5 Rana catesbeiana] and the Cane Toad Rhinella marina [5 Bufo marinus]) both possess potent chemical defenses (Kats et al. 1988; Crossland et al. 2008; Adams et al. 2011; Szuroczki and Richardson 2011). Indeed, the distinctive bufadienalide toxins (cardioactive steroids; Hayes et al. 2009) of Cane Toads have been the primary mechanism for their devastating impact on native predators in Australia (Shine 2010). The success of the Cane Toad invasion has been widely attributed to the inability of native predators to tolerate these toxins, rendering the toads invulnerable (e.g., Covacevich and Archer 1975; Burnett 1997; Letnic et al. 2008). "
    Herpetological Monographs 12/2015; 29(1):28-39. DOI:10.1655/HERPMONOGRAPHS-D-13-00007 · 1.73 Impact Factor
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    • "Toads arrived in our study area in 2005 (Brown et al. 2006). Cane toads possess highly toxic defensive compounds, and many native predators (including fishes, frogs, lizards, snakes, crocodiles and marsupials) have been fatally poisoned when they have attempted to eat the invasive toads (Shine 2010). In our study area, cane toads remain active year-round but tend to be restricted to sites with permanent water during the dry season. "
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    ABSTRACT: Although generalized habitat use may contribute to the success of invasive taxa, even species that are typically described as habitat generalists exhibit non-random patterns of habitat use.We measured abiotic and biotic factors in 42 plots (each 100 × 10 m) along a 4.2-km long unpaved road in tropical Australia, at a site that had been invaded by cane toads (Rhinella marina Bufonidae) seven years previously.We also counted anurans at night in each of these plots on 103 nights during the tropical wet season, over a five-year period, beginning soon after the initial toad invasion. Spatial distributions differed significantly among adult male toads (n = 1047), adult female toads (n = 1222), juvenile toads (n = 342) and native frogs (Cyclorana australis Hylidae, n = 234). Adult male toads were closely associated with water bodies used as calling and/or spawning sites, whereas adult female toads and native frogs were most commonly encountered in drier forested areas on sloping ground. Juvenile toads used the margins of the floodplain more than conspecific adults did, but the floodplain itself was rarely used. Understanding which components of the habitat are most important to specific age and sex classes within a population, or how invasive species differ from native species in this respect, can clarify issues such as the spatial and temporal location of ecological impact by an invader, and the most effective places for control of the invader with minimal collateral effects on the native biota.
    Austral Ecology 09/2015; DOI:10.1111/aec.12279 · 1.84 Impact Factor
    • "Ensuring the barrier's effectiveness will require restricting water access across a 100km-wide strip of suitable coastal habitat (Tingley et al. 2013a). The barrier needs to be this wide because cane toads at the invasion front have evolved to disperse faster than their counterparts in eastern Queensland (Phillips & Shine 2006; Phillips et al. 2010). The invasion front now moves more that 50kms in a season, whereas their long-established conspecifics typically travel less than a fifth of this distance (Phillips et al. 2008; Alford et al. 2009). "
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    ABSTRACT: Anthropogenic threats often impose strong selection on affected populations, causing rapid evolutionary responses. Unfortunately, these adaptive responses are rarely harnessed for conservation. Here, we suggest that conservation managers should pay close attention to adaptive processes and geographic variation, with an eye to using them for conservation goals. Translocating pre-adapted individuals into recipient populations is currently considered a potentially important management tool in the face of climate change. Here we point out that targeted gene flow could have much broader application in conservation, with uses ranging from the management of invasive species and their impacts to controlling the impact and virulence of pathogens. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Conservation Biology 08/2015; DOI:10.1111/cobi.12623 · 4.17 Impact Factor
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