Tuesday, June 01, 2004
Survival of the fittest comes to Darwin
'Killer toads march on city' screams a headline from the Telegraph:
Both before and since the insecticide era, farmers have sought to control insects by bringing in predators, often other insects but in this case toads. Indeed, the TigerHawk sister is an expert on the subject and no stranger to its attendent controversy:
Since Professor Henneman now teaches a course on invasive species at the University of Montana-Western, perhaps the toads of Darwin will qualify for the syllabus.
Back in Australia men and nature are, to some degree, striking back:
Nevertheless, these toads are hard to defeat:
Naturally, I wondered if you could build a fence around Darwin to keep the warty little bastards out. Sure enough, I wasn't the first person to think of the idea (albeit with respect to a national park, rather than the city of Darwin):
UPDATE: The TigerHawk sister reports that she has, in fact, included the cane toad problem in her "invasive species" course since 2002. In other words, she's "all over it like toxins on a cane toad."
They are fat, warty and deeply unloved, and they threaten to shatter the cherished outdoor lifestyle of Australia's tropical north.
Cane toads, brought from South America to Queensland in the 1930s in a failed attempt to control sugar-cane beetles, are now advancing on Darwin, capital of the Northern Territory....
The toads' skin is so toxic that it can kill cats or dogs unfortunate enough to mistake them for a tasty snack.
They can prove fatal to curious toddlers who pick them up or play with them. Even their eggs and tadpoles are poisonous.
Both before and since the insecticide era, farmers have sought to control insects by bringing in predators, often other insects but in this case toads. Indeed, the TigerHawk sister is an expert on the subject and no stranger to its attendent controversy:
To control weeds, bugs, and even diseases, some agricultural experts, foresters, and conservationists see the introduction of non-native species as environmentally friendlier than the use of chemicals such as insecticides and pesticides...
The use of biological controls, however, is controversial. Some scientists argue that species introduced as biocontrols can run amok in the ecosystem and do more damage than the pest or weed they were enlisted to destroy.
"At least chemicals are not a permanent addition to the environment, as biological organisms are," said Laurie Henneman, a co-author of the paper and a colleague of Memmott's at the University of Bristol.
Since Professor Henneman now teaches a course on invasive species at the University of Montana-Western, perhaps the toads of Darwin will qualify for the syllabus.
Back in Australia men and nature are, to some degree, striking back:
Squashed bodies line the Arnhem Highway (Yuck - ed.), the main road into the park, which lies 140 miles east of Darwin.
Some species are learning how to deal with the toads. "Crows have learned to flip them over and eat their bellies out, avoiding the poison glands," Dr Kennett said.
"Crocodiles rip the toads' skin off with their teeth and thrash them around in the water to wash out the toxins."
Nevertheless, these toads are hard to defeat:
Cane toads are extremely prolific. They mate like rabbits, and a female can produce a fresh batch of toadlets every month. Cane toads are also tough as nails, able to withstand the impact of a 4-wheel drive. Since the 1930s, the toads have advanced through Australia at a rate of about 30 kilometers (19 miles) per year.
Naturally, I wondered if you could build a fence around Darwin to keep the warty little bastards out. Sure enough, I wasn't the first person to think of the idea (albeit with respect to a national park, rather than the city of Darwin):
Many biologists doubt that a fence would stop the cane toads. Some toads might swim around the fence and others might hitchhike into the peninsula on cars, say the biologists. Once inside, even a few toads could explode in number and quickly colonize the peninsula.
Delia Lawrie, an elected representative, agrees that a fence wouldn't be totally toad-proof. She told the Canberra Times that a fence might still work if it was regularly patrolled and any toads that got into the peninsula were caught and exterminated. "We absolutely have to take action," she said.
UPDATE: The TigerHawk sister reports that she has, in fact, included the cane toad problem in her "invasive species" course since 2002. In other words, she's "all over it like toxins on a cane toad."
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