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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 Dr Freeland Volume 2 Cane Toad Inquiry Report 155 The Parks & Wildlife Commission jointly funded and conducted the establishment of the Kakadu monitoring plots. This includes the most recent report by Watson and Woinarski (2003) as well as more detailed work on the Quoll. The discovery of chytrid fungi infecting native frogs (and probably causing a series of extinctions of frog species) and cane toads in Queensland raised the prospect of cane toads possibly having introduced the fungi to the Northern Territory, with potentially significant impacts beyond those caused by the cane toad alone. Northern Territory samples of cane toads, native frogs from within the cane toad's range and native frogs outside the cane toads range were collected by Parks and Wildlife Commission staff and analysed by James Cook University. No chytrids were found. After a considerable period of planning and preparation the Commission, in collaboration with the Northern Land Council, Traditional Owners and Parks Australia undertook the introduction of Quolls to islands off the Territory's coast i.e. places that will hopefully remain free from cane toads. This effort is highly commendable. Translocation of native species outside their native ranges and reintroductions of threatened species within their former ranges are serious and highly technical matters that raise numerous questions related to both the potential for success of such activities and the potential of translocations in particular to have adverse environmental impacts. This is one of the reasons the Territory's legislation provides the option to develop of Plans of Management dealing with management of native species. This is the only way serious issues of public concern can be addressed in an open and accountable fashion. Because of the absence of a Plan of Management I am unable to determine whether some issues of serious concern were dealt with. I assume they have been but will briefly outlines what to me are the major concerns. In the recent geological past the islands used for the translocations were part of the mainland and as they appear to contain habitat suitable for Quolls, can be assumed to have once had quolls. The questions is why did these populations become extinct, and if this is the long term fate of the translocated quolls, what management practices are to used to prevent that fate? The islands appear to be relatively small and of necessity are likely to have an even smaller area of habitat suitable for quolls. Is that habitat large enough to sustain a population of Quolls of sufficient size to minimise the probability of long term population extinction. The smaller a population the higher it's probability of random extinction, and unless it can reach and be maintained at its Minimum Viable Population Size the probability of extinction is close to certain. Populations introduced to small islands can underdo rapid growth utilising an initially abundant food source, only to rapidly "over-shoot" and crash with an again a high probability of extinction if the island is not large enough. The islands have been the subject of fauna surveys and these data could have been interpreted so that the public had confidence in the potential survival of the Quoll population and what if any would be the adverse impacts on native species on the islands. My final concern is that individuals taken to the island may have been individuals subjected to de-worming or other health control procedures. Animal populations without their parasites and pathogens loose a critical mechanism for population regulation and the consequences can be disastrous. Similarly, the stability of ecological communities as a whole may be a consequence of parasites and pathogens, particularly those associated with predators (e.g. the Quoll) and having live cycles impacting on more than