Australia faces serious ecological threats posed by feral animals and out-of-control wildfires. Non-native species gone wild have contributed to both problems, and one biologist is suggesting that Australia fight fire with fire by introducing more non-native species.
In an article in Nature, David Bowman, a biology professor at the University of Tasmania, lays out his vision for dealing with Australia's ecological problems. The continent suffers from wide ranging wildfires, which last year burned about five percent of the continent.
The fires feed on grasses, specifically a giant invasive species called gamba grass. Unlike most native weeds, gamba grass continues to grow during the dry season, making it an excellent source of fuel for intense flames.
Australia also has to deal with invasive fauna as well as flora: when domesticated animals like pigs, horses, buffalo, and camels escape or are released into the wild, they develop large feral populations. These mammals threaten the Australian ecosystem because of "the lack of any population control," explains Bowman. The once-domestic animal populations can increase quickly without warning, spreading into new territory and out-competing native species.
You might think that the feral animals could feed on the overgrown grasses and reduce the wildfires without human intervention. But remember the gamba grass? At up to 4 meters high, it's too big for these herbivores to handle.
Once Australia was home to huge animals called megafauna, which might have been able to control the grass growth and to out-compete the invasive herbivores. Just one glitch — the megafauna died out about 50,000 years ago in the Pleistocene extinctions.
Since then, the Aboriginal custom of patch burning, or setting small fires to burn off excess grass growth, has kept out-of-control fires from erupting, but this tradition has since been disrupted. Bowman suggests another way — importing large herbivores and predators:
I think that another, more holistic approach can address Australia's ecological problems. Specifically, we must restabilize food webs (now out of balance because of the Pleistocene extinctions), the loss of the Aboriginal traditions of patch burning and hunting, and the ad hoc release of non-native animals and plants. We must introduce and manage predators to control the feral animals, and bring in herbivore species to graze the flammable grasses - which we can better control using small fires as ‘uber-herbivores.'
Bowman's plan involves restoring traditional Aboriginal patch burning and hunting, and bringing in new animals to take care of the rest:
Indeed, existing ranger programmes that enable indigenous people to return to their roots - by hunting buffalo or managing natural resources - have been shown to have social and health benefits for this disadvantaged sector of the Australian community.
The paper Bowen cites is this 2009 paper published in the Medical Journal of Australia. Setting aside the uncomfortable notion that one group of people should do a specific kind of work, why should Aborigine buffalo hunting be any more effective than the type of buffalo hunting that Australians are already using in an attempt to control feral animals? Why can't non-native Australians learn to practice traditional patch burning methods? Bowman thinks that there are enough Aboriginal hunters to deal with the feral animal problem, but surely the more people who can help out with these environmental issues, the better.
And animals can help too: a key aspect of Bowman's plan involves introducing more non-native species in order to control the ones that are already there. Large herbivores like elephants and rhinoceroses could fill the void left by the extinct megafauna, chomping down on gamba grass to keep it under control, as well as competing for resources with the feral herbivores. Plus, this would serve the added purpose of protecting these animals from poaching in their indigenous homes.
Still, elephants in Australia? Bowman knows the suggestion sounds odd:
The idea of introducing elephants may seem absurd, but the only other methods likely to control gamba grass involve using chemicals or physically clearing the land, which would destroy the habitat…I realize that there are major risks associated with what I am proposing. It would be essential to proceed cautiously, with well-designed studies to monitor the effects.
To control the new species, Bowman takes inspiration from nature reserves. Selectively placed fences, a carefully controlled food and water supply, and a well-organized program of breeding and hunting would ensure that the introduced animal populations remained in check. Why couldn't these methods also work on the feral creatures? Bowman dismisses the idea because "the animals are too widespread to be controlled other than by shooting."
While letting large herbivores manage the grasses doesn't sound so bad, the notion of having predators tackle the feral animals may carry greater risk. In addition to Aboriginal hunters, Bowman indicates that native dingoes and non-native predators, such as Komodo dragons, could reduce the feral fauna's numbers. Instead of poisoning the dingoes, Bowman proposes that humans let the populations of these wild dogs grow so they can prey on the feral animal populations.
But there were good reasons that humans started poisoning dingoes in the first place. The Australian wild dogs scavenge from humans and can pose as much of a threat as obnoxious feral animals would. As for importing Komodo dragons to snack on the wild herbivores, Aussies may want to rethink a predator that "will eat almost anything...even...humans." These beasts are downright scary, even for a continent filled with threatening animals. Can we really come up with no better solution for eradicating feral animals than siccing even more dangerous creatures on them?