Tuesday, February 17, 2015

Controlling cane toads in Australia

Cane toads were introduced to Australia in 1935 in an attempt to control insects which were feeding on the sugar cane crops.  While they don't appear to have had much impact on the insects they were supposed to target, they have become an incredibly successful invasive species.  The toads spread disease, most species which try to eat the toads will succumb to the poison, and have caused a decrease in biodiversity and populations numbers among many native insectivores, often by the toads consuming the same prey.  There have been many methods tried to control the toads' spread, but none have been very successful.  Trapping, sterile male releases, and introduction of a virus have all been evaluated, but ineffectiveness and serious concerns of off-target, native species effects and have put a halt to these studies.

However, a new study has come up with a promising solution.  As cane toads are not native to Australia, they are not acclimated to the dry, hot seasons and survive by visiting human-made dams to cool down.  By putting up toad-proof fences they are unable to enter the dams and, as the toads are still drawn to the water, the dams act as large scale traps and toads will perish outside the fences.  Furthermore, due to the outright reduction in toad population and fewer surviving toads to spawn a new generation, areas around fenced dams have shown that the number of toads are repressed the next year.  Areas around unfenced dams have a population 10 to 100 times higher.  By limiting the toads' access to open water, this method could help slow the invasion across arid regions of Australia.

To read the article detailing the efforts: Long-term control of cane toads demonstrated