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KTB “Iconic Species” monitoring program. |
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The cane toad invasion of Kakadu National Park in the NT saw a sharp rise in the number of known species to suffer badly from the impact of cane toads. While toads have now been slowly invading large areas of northern Australia for the past 76 years little has been understood of the full impact of the toad on our native species. Considerable scientific research had been undertaken in Kakadu prior to the arrival of the cane toad and for the first time scientists began recording evidence that entire species were being wiped out, giving little chance for some species to make the so called ‘come-back’ some scientists advocate happens when toads either ‘move on” or population numbers reduce due to diminishing food resources. Recent floods in areas of Queensland that appeared to have had a reprieve from cane toads have seen a huge escalation in numbers once again. This has meant that any build-up in food resources that might have enabled some native species that had survived the first series of toad invasions were once again being forced not only to compete for food resources but for new generations of native species also having to ‘learn’ not to touch the toad.
The KTB “Iconic Species” monitoring program is designed to encourage community members across the Kimberley to select a known native species that experiences a sharp decline when toads first invade an area, or to select their favourite native species, record its number in a known area and then monitor it prior to and after the toads arrive.
Please contact KTB on 08 91682576, email admin@canetoads.com.au or follow this link for a copy of our “Iconic Species” data recording and monitoring form.
ICON animal |
Impact of Cane Toads |
Location in NT |
Source/Principal Author |
Northern Quoll
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100% loss of animals
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Kakadu
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Meri Oakwood
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Goannas/Monitors
Yellow spotted,
Mitchells, Mertens ,
Sand/Goulds Goanna
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90% loss of animals
No recovery since 2003
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Daly River,
Manton Dam,
Kakadu
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Sean Doody
Tony Griffiths |
Frilled Neck Lizard
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Not well understood, up to
100% loss
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Top End
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Graham Sawyer
Community groups |
Freshwater Crocodile
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77% loss of animals
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Victoria River
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Mike Lentic |
Pygmy. Freshwater
Crocodile |
Up to 100% loss of
animals |
Bullo River |
Adam and Erin
Britton |
Northern Blue-Tongue
Lizard |
100% loss of animals |
Fogg Dam |
Greg Brown
Sam Price-Lees |
Small Skinks
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Dramatic reduction in
number and types of species
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Jaspers Gorge
Katherine George
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Lyall Grieve
Tourism Operators |
Brown Snake, Death
Adder and other
snakes |
Up to 90% loss of animals, some research suggests morphological
change and recovery of some species |
Top End |
Observations from
Rangers- Kakadu
Mattias Hagman
Ben Phillips |
Rainbow Bee Eater |
30% loss of breeding
locations |
SE Qld |
Christopher Boland |
Insects |
In tropical floodplain ecosystems, cane toads consume more than 4 times amount of insects than native frogs
Cane toads significantly deplete insect food resource |
Fogg Dam
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New Caledonia
Matt Greenlees
Mike Tyler |
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“Iconic” Key Species for recording and monitoring.
Key species that you may be interested in keeping an eye out for and recording (these species are now accepted as being most at risk from Cane toads):
Northern Quoll (100% loss recorded in Kakadu)
- Goannas - Sand Goanna, Yellow Spotted Goanna, Spotted Tree Goanna, Merten’s Water Monitor, Mitchells Water Monitor (90% loss recorded in the Daly) (KTB have also noted the Gould is also at risk).
- Frogs - Ornate Burrowing Frog, Green Tree Frog, Northern Dwarf Tree Frog, Flat headed frog (calls are a great way of indentifying species)
- Skinks - Blue-tongued Lizard (all smaller skinks are also likely to be impacted) (100% loss feared for the Kimberley) (KTB have also noted that many of the small skink species begin to disappear when competition for food resources starts).
- Dragons – Frilled neck Lizards
- Snakes - Carpet Python, Yellow Tree Snake, Black headed python, Banded tree snake (Snakes that KTB have noted also at risk are the King Brown and Death Adder).
- Birds - Black Bittern (heron), Blue-winged Kookaburra and night birds (KTB have noted that Pelicans also die when they inadvertently scoop up cane toad tadpoles. We have also recorded large numbers of deaths amongst the various birds of prey when toads first invade an area ).
- Freshwater crocodiles (77% loss recorded in the Victoria River)
- Ghost bats
- (KTB have also noted that both the short necked and long necked turtle also die in large numbers when toads first arrive in a system and start breeding).
This is just scratching the surface – many of the above species are impacted as predators of cane toads or tadpoles. The indirect impacts of resource competition and the cascading impacts when a predator is removed from the food web have not been recorded other than anecdotal reports from crocodile farmers that saltwater crocodile breeding has accelerated since lizard species have been removed from the system.
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