By Richard Black

Environment correspondent, BBC News

Dingoes spread widely across Australia after their introduction

Re-introducing dingoes across tracts of Australia could have benefits for wildlife and possibly cattle farmers. Researchers found that dingoes suppress populations of kangaroos and red foxes, which are big consumers of vegetation and small mammals respectively. Writing in the Royal Society's journal Proceedings B, they say the benefits of dingoes outweigh concerns over their presence as an "alien predator". The wild dogs were brought to Australia about 5,000 years ago. Their appetite for sheep means they have been expelled from large swathes of the country, notably the productive farmlands of New South Wales and Victoria, where a "dingo fence" more than 5,000km long has been erected to keep the predators out. You basically have two ecological universes - a system with dingoes and a system without dingoes - they are completely different places

Dr Michael Letnic But this may have contributed to the demise of some native animals and the endangerment of many more. "There is a lot of pressure to get rid of dingoes, and they can do damage," said Michael Letnic from the University of Sydney. "The prevailing view that they're introduced and must be removed. "But dingoes suppress fox and kangaroo numbers, and when you don't have dingoes in the system, kangaroos basically eat all the herbiage and foxes take all of the prey." Settled argument Dr Letnic's team surveyed pairs of sites located close together but on opposite sides of the dingo fence, looking at the abundances of different species. Where dingoes were absent, kangaroos and foxes flourished, while native rodents, marsupials and grasses were all diminished. WILD DOG WILD FACTS Descended from a domestic dog brought in from Indonesia The social dingo is a pack hunter but will also scavenge Females only breed once a year, having four or five pups Dingoes hunt kangaroos, and will banish foxes from land they occupy. "You basically have two ecological universes - a system with dingoes and a system without dingoes - they are completely different places," Dr Letnic told BBC News. There was no discernible impact on cats - another introduced predator blamed for the decline of smaller native animals. Using Australian government data on endangered species, the researchers calculated that 16 threatened mammals would benefit from the presence of dingoes, while the wild dogs would only be detrimental to three species. The dingo came to Australia with settlers from what is now Indonesia. The introduction almost certainly brought about the demise of the thylacine or Tasmanian tiger, the top indigenous predator - probably because the dog was a more efficient hunter. The dingo may have taken up the thylacine's ecological role of controlling kangaroos. Michael Letnic's team is not the first to suggest that dingoes benefit local species; but in quantifying the likely impact, he may have produced an effective argument for their re-introduction. Even more effective in a country where farming is hugely important may be his contention that dingoes probably increase the profitability of cattle farming, by removing kangaroos that otherwise eat vegetation. "The chances are that [cattle farmers] lose more by what kangaroos do than by what dingoes do," he said. Richard.Black-INTERNET@bbc.co.uk



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