Image: The relentless march of the toad now means that they have expanded their range to encompass more than a million square kilometres of tropical and sub-tropical Australia and have even reached as far as northern NSW.
Original Published Date: 
Tuesday, February 16, 2016

Research undertaken by Australian Laureate Fellow, Professor Rick Shine, and his team at The University of Sydney,shows that the annual rate of progress of the cane toad invasion has increased five fold since their introduction into Queensland in 1935. Toads expanded their range by about 10km a year during the 1940s to 60s, but are now invading new areas at a rate of over 50km a year. By attaching radio transmitters to the toads, researchers have found that toads with longer legs not only move faster and are the first to arrive in new areas, but also that those at the front have longer legs than those in older (long-established) populations. They also found that these long-legged toads had more endurance, travelling about half a kilometre further in a three-day period. “When an invasive species is first introduced, the population remains low for a few generations before exploding,” Professor Shine said. “It’s likely that such lags reflect, at least in part, adaptive changes in the invader to suit it to the new environment. These findings indicate that evolutionary forces are likely to fine-tune organism traits in ways that facilitate more rapid expansion of the invading population. Hence, control efforts against feral organisms should be launched as soon as possible, before that invader has time to evolve into a more dangerous adversary.”

Media issued by The University of Sydney.

Photo credit: 

Image courtesy: The University of Sydney.