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Cane Toads

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brooke freeman

on 18 November 2014

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Transcript of Cane Toads

Recent Evolution in Australia
As you can see in figure one cane toads are spreading very quickly. They were introduced in Queensland but are breeding fast and expanding even faster.
This map shows that in the future,
Cane Toads may be living in
Tasmania, Perth,
Victoria and even the Northern
Territory.

Cane Toads introduced to Australia
In the 1930’s sugar cane growers in Queensland were had lots of damage to there crops. This was because of the beetles – especially the frenchi beetle and the greyback beetle. The Queensland Department of Agriculture decided to do something about it. The chemicals that were used to kill insects at that time were very bad. So they needed to do something less harmful. They decided to introduce about 100 cane toads and around 3000 tadpoles from Hawaii, to kill the pests and therefore protect the sugar canes. Soon after the cane toads arrived in Australia, scientists discovered that the cane toads were not protecting the sugar canes but causing more damage and becoming a pest.

The Cane Toad Invasion
The first few decades after toads were released in Queensland, they expanded at about 10 km per year. That rate then began to increase fairly quickly, and now averages about 55 km per year. There is an estimated 200 million just in australia. The reason they spread so quickly is because instead of going through the scrub they follow roads and cattle tracks. But the biggest factor is because of evolution. They have evolved to move more rapidly with longer legs and different behaviours. This is why they move west about five times faster than in the early years of toad invasion.

Where they live in Australia
Figure 1: Distribution (1935 to 2004) and predicted
spread of Cane Toads in Australia

Cane Toads
Snakes evolving to avoid Cane Toads
Cane Toads evolving to live in Australia
Would the Riverland be affected if cane toads were to arrive here
Since toads have arrived in Queensland, snakes have been threaten which has caused snakes to evolve. n previous research, Phillips sampled snakes from around Australia and found the cane toad toxin did not affect all snakes the same way.

He found that larger snakes were less affected by toad toxin. In particular, the snakes with the larger ratio of body-length to head-size were less affected.

The bigger a snake, the smaller its head is compared to its overall body length. And since the size of a snake's head limits the size of its prey, this means a larger snake is less likely to eat a large enough toad to poison it, said Phillips.Unfortunately Cane toads have caused alot of evolution in lots of different animals in Australia.
The toads have evolved larger legs; this makes the travel farther. As a consequence of their longer legs, larger bodies, and faster movement, about 10% of cane toads have also developed arthritis. It was estimated that cane toads migrate at an average of 40 kilometers per year as of 1994.
Bibliography
"Honolulu Zoo Cane Toad".
"Cane Toad Bufo marinus".
http://search.proquest.com/docview/862947521/fulltext?accountid=4117
http://www.environment.gov.au/biodiversity/invasive/ferals/cane-toads.html
Clarke, G. M., Gross, S., Matthews, M., Catling, P. C., Baker, B., Hewitt, C. L., Crowther, D., & Saddler, S. R. 2000, Environmental Pest Species in Australia, Australia: State of the Environment, Second Technical Paper Series (Biodiversity), Department of the Environment and Heritage, Canberra.
http://australianmuseum.com/Cane-Toad
"Institute for Molecular Bioscience, Killing off the cane toad". Retrieved 2006-12-06.
"Toxic Toads Evolve Longer Legs, Study Says. 15/02/06. National Geographic News". Retrieved 2006-05-19.
Henry Fountain (16 October 2007). "Arthritis Fails to Slow Invading Toads in Australian Fields". NY Times. Retrieved 2007-10-27.
Tyler, M. J. (1994). Australian Frogs A Natural History. Reed Books. p. 112. ISBN 0-7301-0468-0.
http://www.abc.net.au/science/articles/2004/11/30/1250708.htm
Luckily in the Riverland, unlike Queensland and Darwin, is reasonably dry and has little rain. Cane toads love the wet season therefore it is very unlikely that Cane Toads will ever reach the riverland.

The riverland would be heavily under threat if cane toads were ever to arrive here. Cane Toads eat almost anything they can swallow, Mainly beetles, bees, ants, winged termites, crickets and bugs. Also marine snails, smaller toads and native frogs, small snakes, and small mammals are occasionally eaten by Cane Toads. So wherever cane toads go they are going to cause harm to the environment.


Taking over Australia
BBC Worldwide Published on 10 Sep 2014 - Youtube

Figure two
Department of Environment and Primary Industries - June 2014
Full transcript