ARTICLES
Love them or Hate them, Cane Toads are Here to Stay (continued)
they commenced another propaganda campaign, this time
painting toads as a “Judas” animal. Toads should have done the
right thing and stayed in the cane fields and just eaten the cane
beetles, but they didn’t. They betrayed Australians and now they
were threatening our animals. Once domestic dogs began to fall
victim to toads, the politicians were able to deflect the public
anger totally onto the toads and away from themselves.
Even to this day the State of Queensland does not recognise
toads as a “pest” species. To do so would reignite their role in
importing toads, and also place some obligation on the current
Government leaders to do something about controlling toads. For
a while toads remained in Queensland, and Queensland suffered
because of it.
Cane toads were first recognised as a pest species by the Western
Australian Government, where they were listed as vermin under
the state’s Vermin Act in 1950. No serious attempts were made to
raise cane toad control as a national issue until the early 1980s.
The Commonwealth first took some responsibility for the problem
in 1986, with federal funding and establishment of a cane toad
Research Management Committee.
Why Cane Toads are such a Problem
In Australia, cane toads have no natural enemies. Their toxin can
kill most native animals that normally eat frogs. They therefore
pose a risk to both native fauna and pets such as cats and dogs.
Cane toads can use a wide variety of habitats, and thrive in urban
and disturbed areas. They have a voracious appetite and can eat
a lot of different foods. They also breed quickly, allowing them to
rapidly colonise and dominate an area.
Figure 2 The progressive Cane Toad spread all across
Queensland
As populated areas began to increase, the rate of cane toad
spread also increased. Professor Rick Shine (Figure 3) and his
team at the University of Sydney have been studying the progress
of toads and have discovered some amazing facts about toads
that explain why they are so successful in Australia.
These abilities give cane toads a competitive advantage over
native species. Native frogs control insects that may otherwise
become pests, and are in turn food for many native animals.
Populations of many native frogs have declined severely in recent
times, and some species are threatened with extinction. Spread
of the cane toad may increase these threats.
How Quickly are Toads moving across
Australia?
In the early years (up to the 1960’s or so), the toad invasion
front advanced fairly slowly – about 10 km each year. Toads
radiated out from the cane fields where they had been released
and quickly found new breeding sites to colonise. The main
direction of spread was southwards, down the Queensland coast
(Figure 2). But then disconnected populations of toads began to
appear. Some of these populations were hundreds of kilometres
apart – clearly toads were not hopping these distances in such
a short time.
Figure 3 Rick Shine with a Toad
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SCIENCE EDUCATIONAL NEWS VOL 67 NO 2