Cane toads, brought to Queensland from South America in the 1930s to tackle sugarcane beetles, have become Australia's latest big alien menace. The toads have been gradually spreading across tropical northern Australia, and citizens of Darwin are bracing for an invasion when the next wet season starts in December.
The highly fecund cane toads (Bufo marinus) are a threat to native wildlife because of a poisonous sac at the base of the head that can kill any predators, from crocodiles to cattle, that take a nip at them. They have been implicated in the recent drastic decline of quolls, cat-sized marsupials. Authorities worry that they will cut a swath through native frogs, snakes, and goanna lizards in the Northern Territory's famous Kakadu Park.
Trapping, monitoring, and public education activities are now in high gear. Zoologist Gordon Grigg of the University of Queensland in Brisbane and others are looking for "toad-specific" solutions, including scents and sounds that will draw the animals to traps, pheromones that might be used to disrupt breeding cycles, and toxins special to the cane toad. In the long run, government scientists hope that genetic engineering will allow them to throw a wrench into tadpole development.
That solution is still far away, says Adelaide University zoologist Michael Tyler. Amphibians are rarely invasive species, he notes, so scientists still know little about the toad and its potential Achilles' heel. That is why, he says, "everything we've tried so far has been unsuccessful."
CREDIT: FROGWATCH |
