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Sessional Committee on Environment and Sustainable Development Written Submissions Received Volume 2 Issues associated with the progressive entry into the Northern Territory of Cane Toads October 2003



Sessional Committee on Environment and Sustainable Development Written Submissions Received Volume 2 Issues associated with the progressive entry into the Northern Territory of Cane Toads October 2003

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Tabled Paper 1123


Tabled Papers for 9th Assembly 2001 - 2005; Tabled Papers; ParliamentNT




Tabled by Delia Lawrie


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Written Submissions Environment Australia Part I Volume 2 Cane Toad Inquiry Report 105 Based on these records, within Kakadu cane toads are spreading north-west at a rate of about 60km per year. EA considers it likely that cane toads will continue to spread at a similar rate across Kakadu and the rest of the Top End of the Northern Territory, much of which affords suitable habitat and abundant food resources for cane toads. Effects and risks of cane toads Cane toad biology is well documented as a result of many years research into biological control methods. The key features of cane toads that lead to significant effects on Australian native species are their toxicity to potential predators, their fecundity, their ability to disperse over long distances and their adaptability to a wide range of habitats and prey species. The immediate effects of cane toad interactions with humans, domestic animals and many Australian native species are known from anecdotal evidence and research. Because cane toads produce a toxin that is lethal to most Australian native species, animals that attempt to eat cane toads, or their eggs or tadpoles often die. Cane toads also consume a wide variety native species, mainly invertebrates, as prey. Because of their large numbers and wide range of prey items, it is likely that cane toads compete with native species for food but little is known of these competition effects. The toxin is also potentially lethal to humans, domestic dogs and cats if ingested, however humans tend to avoid contact with the toads and are easily educated about the dangers. Some domestic pets are killed by contact with cane toads but many learn to avoid them. As a result, cane toads do not pose a significant direct risk to human or domestic animal populations. Based on the toxicity, fecundity, migratory behaviour and adaptability of cane toads, EA considers that it is highly likely that cane toads will adversely affect populations of many native species in the Northern Territory. However, until recently there had been little research conducted on the indirect and long-term effects of cane toads on Australian native species and ecosystems. As a result, there is as yet little quantitative data on the likely long-term effects of cane toads on native species and ecosystems. This lack of quantitative information was of increasing concern to EA and the Kakadu Board of Management as cane toads approached Kakadu and no biological control method had been found. Consequently, EA took the following steps to identify the likely effects of cane toads on native species in the Kakadu region. ERISS prepared a preliminary risk assessment of the impact of cane toads (ERISS has submitted this report to the Inquiry). This risk assessment rated northern quolls, several goanna species and several snake species as most likely to be seriously affected by cane toads. Many other species are also likely to be adversely affected. Parks Australia contributed funds to extend a frog monitoring program, being conducted by Dr Gordon Grigg, University of Queensland, into Kakadu (see synopsis of Roper River area work at Attachment B). None of the monitoring sites in Kakadu had been reach by cane toads as at May 2003. Parks Australia engaged Dr John Woinarski, NT Parks and Wildlife Commission and Ms Michelle Watson to conduct a series of fauna surveys in Kakadu, at sites that had been surveyed up to 25 years ago, to examine faunal changes since the