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
Tabled Paper 1123
Tabled Papers for 9th Assembly 2001 - 2005; Tabled Papers; ParliamentNT
2003-10-16
Tabled by Delia Lawrie
Made available by the Legislative Assembly of the Northern Territory under Standing Order 240. Where copyright subsists with a third party it remains with the original owner and permission may be required to reuse the material.
English
Tabled papers
application/pdf
Copyright
See publication
https://www.legislation.gov.au/Details/C2019C00042
https://hdl.handle.net/10070/307061
https://hdl.handle.net/10070/346011
Written Submissions Dr Brown Volume 2 Cane Toad Inquiry Report 147 and which animals attempt to eat them in the field. By closely monitoring the toad population we may also be able to notice any unusual episodes of mortality among them. At this point, we expect that many species of snake and other large reptiles in the Top End will be detrimentally affected by the arrival of cane toads. Populations of keelback and slatey-grey snakes (two species which we study intensively) are likely to be less effected than other species. Although the impact on most species is likely to be severe, we cannot say how severe. The fate of populations of susceptible snakes depends on several unknown factors. It depends on how much variation there is among individual snakes in their readiness to try to eat a cane toad and on individual variation in how badly toxin effects them. We expect that once breeding populations of cane toads become established and large numbers of eggs, tadpoles and small toads appear, there will be immediate dramatic declines in many populations of reptiles. Until we actually witness the extent of these short-term population declines we won't know the longerterm prognoses. Individuals that won't attempt to eat toads or that are less effect by the toxin may survive the initial impact. Eventually, populations may rebuild from these individuals and the offspring may display the characteristics (e.g. avoidance of toads, toxin tolerance) that allowed the parents to survive the presence of cane toads. This submission to the committee attempts to identify possible ecological effects of the arrival of cane toads. The real extent of the cane toads effects will not be known until they arrive. But, when the toads have arrived, our research will provide a detailed account of what effects they are having on reptiles and frogs. The world is unlikely to come to an end when cane toads reach Darwin's rural area, but we think its inevitable that several species of reptiles and likely some native frogs will become much rarer and some may even disappear. Such impacts may only be noticed by biologists, naturalists or people who spend a lot of time in the bush. People who limit their outdoor activities to backyard barbies are unlikely themselves to notice a serious decline in, for instance, ornate burrowing frogs or death adders. What everyone will notice is the toads themselves. They are likely to reach extremely high initial population densities and they are large and conspicuous animals that many people find unpleasant. Until people become accustomed to the presence of toads, they might affect enjoyment of outdoor activities for some. Ecotourism might conceivably be adversely affected by the presence of large numbers of toads or decline in populations of iconic animals (frillnecked lizards). Aboriginal communities that rely heavily on bush tucker may be affected if populations of goannas or turtles decline permanently. Dr Greg Brown