THE eastern hare-wallaby is gone. The lesser bilby is no more. In the past two centuries, these and 16 other mammals have become extinct in Australia 鈥� almost half the mammalian species lost worldwide over that time.
Changes in how people use fire to clear land, the introduction of rabbits and disease, and sheep farming have in the past been blamed for the extinctions. Now a team led by Chris Johnson of James Cook University in Townsville, Queensland, says the cause is far simpler: the persecution of mainland Australia鈥檚 only top predator, the dingo. 鈥淲here there are no dingoes, introduced predators are rife, and up to 65 per cent of ground-dwelling mammal species have disappeared,鈥� Johnson says. 鈥淚f dingoes hadn鈥檛 been so savagely persecuted, we wouldn鈥檛 have had this total catastrophe.鈥�
By mapping habitat type and the range of ground-dwelling marsupials, rabbits, foxes, dingoes and sheep, Johnson鈥檚 team has shown that wherever dingo populations have slumped, prey species such as the lesser bilby have become extinct (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2006.3711). That adds to circumstantial and historical evidence that dingoes protect small marsupials by reducing numbers of introduced predators, such as the fox, whose numbers explode in the dingo鈥檚 absence.
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