The dingo ... poison or let flourish?

Credit: Karen Johnson

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Once a year in the springtime, a lone plane takes off and flies a slow pattern over Carlton Hill station, a 3,600 square kilometre chunk of James Packer's Consolidated Pastoral Company, tucked into the extreme northeast of the Kimberley. As the plane circles, those aboard open up a special metal chute, and drop more that 1,000 little pieces of meat, one by one onto the open scrubland below. Each and every piece is laced with poison.

Besides 50,000 or so head of cattle, Carlton Hill and neighbouring Ivanhoe are home to dingoes, Australia's largest mammalian predator and the bane of graziers across the continent. "They take out cattle, and there goes our livelihood," says Stuart McKechnie, manager of Carlton Hill.

But one man wants the baiting to end, and for dingoes to once again roam Australia's wide-open spaces. According to Chris Johnson of James Cook University, and author of Australia's Mammal Extinctions: a 50,000 Year History, "Australia needs more dingoes to protect our biodiversity."

In the two centuries since Europeans landed, 18 species of native Australian mammals have become extinct - accounting for almost half the world total in that period. Desert rat-kangaroos, lesser bilbies, and pig-footed bandicoots have disappeared, and animals like the northern quoll are in serious decline. In his book, Johnson makes the case that these extinctions were caused by introduced predators - mostly cats and foxes - running rampant. Dingoes, he says, are the only way to control those predators and protect the native mammals that remain.

About 4,000 years ago, Asian seafarers introduced dingoes (Canis lupus dingo) to the shores of Australia. Over the ensuing millennia, these descendants of the wolf spread across the Australian continent and, as the Tasmanian tiger disappeared from the mainland, dingoes became Australia's top predators.

In 1788, Europeans began to colonise Australia. Agriculture spread across the continent, and graziers found that they could not safely keep their cattle and sheep where hungry dingoes lurked. So began one of the most intense, sustained efforts at pest control in Australia's history.

Over the last 150 years, dingoes have been shot, poisoned, and fenced in an attempt to keep them away from livestock. In the northeastern Australian state of Queensland alone, where the state government began rewarding kills as far back as 1877, hunters have collected about 1.8 million bounties for dingo scalps. But at the same time, as graziers tried to eliminate one native pest from Australia, Europeans settlers introduced some more of their own.

In 1860, the rabbit was unleashed on Australia by a wealthy landowner near Melbourne. They exploded across the continent. By 1980, rabbits had blanketed the mainland, save for the north of the Kimberley, the Top End of the Northern Territory around Darwin, and Cape York Peninsula. Rabbits provided a huge prey base for two other introduced species: the feral cat and the red fox.

The interaction between foxes, cats and rabbits is a huge problem for native mammals. In good years, rabbit numbers shoot up, and fox and cat populations grow quickly in response to the abundance of prey. When bad seasons follow, rabbit numbers crash – and the dwindling but still large fox and cat populations are left with little to eat besides native mammals.