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Top predators in terrestrial ecosystems may limit populations of smaller predators that could otherwise become over abundant and cause declines and extinctions of some prey. It is therefore possible that top predators indirectly protect many species of prey from excessive predation. This effect has been demonstrated in some small-scale studies, but it is not known how general or important it is in maintaining prey biodiversity. During the last 150 years, Australia has suffered the world’s highest rate of mammal decline and extinction, and most evidence points to introduced mid-sized predators (the red fox and the feral cat) as the cause. Here, we test the idea that the decline of Australia’s largest native predator, the dingo, played a role in these extinctions. Dingoes were persecuted from the beginning of European settlement in Australia and have been eliminated or made rare over large parts of the continent. We show a strong positive relationship between the survival of marsupials and the geographical overlap with high-density dingo populations. Our results suggest that the rarity of dingoes was a critical factor which allowed smaller predators to overwhelm marsupial prey, triggering extinction over much of the continent. This is evidence of a crucial role of top predators in maintaining prey biodiversity at large scales in terrestrial ecosystems and suggests that many remaining Australian mammals would benefit from the positive management of dingoes.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Terrestrial Ecology
Objective Division:	Environment
Objective Group:	Flora, Fauna and Biodiversity
Objective Field:	Flora, Fauna and Biodiversity of environments not elsewhere classified
Author:	Johnson, CN (Professor Christopher Johnson)
ID Code:	69609
Year Published:	2007
Web of Science® Times Cited:	184
Deposited By:	Zoology
Deposited On:	2011-05-04
Last Modified:	2011-10-06
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