23 January 2008

Are reintroductions doomed to fail?

Cosmos Online
A new study reveals that up to 70 per cent of captive-born carnivores released into the wild lack the skills to survive, with many falling prey to shootings or car accidents.
Are reintroductions doomed to fail?

Limited success: Re-introductions of captive-born carnivores such as the European lynx (Lynx lynx) are often plagued with difficulties. Credit: AFP

SYDNEY: A new study reveals that up to 70 per cent of captive-born carnivores released into the wild lack the skills to survive, with many falling prey to shootings or car accidents.

“Animals in captivity do not usually have the natural behaviours needed for success in the wild. Their lack of hunting skills and their lack of fear towards humans, for example, are major disadvantages,” said Kristen Jule, lead author of the study and expert on animal behaviour at the University of Exeter in England.

“We have suspected for some time that [they] fared less well than wild animals, but here it is finally quantified, and the extent of the problem is critical,” she said.

Lacking basic skills

Detailed in the journal Biological Conservation, Jule’s survey compared the rates of success and failure in 45 studies of carnivore reintroductions. The results showed that captivity can negatively influence a carnivore’s ability to survive in the wild – with animals often lacking the natural skills for hunting, foraging and breeding.

Of the case studies reviewed – covering the reintroduction of captive-born individuals of 17 species from lynx to panthers – Jule’s team found just a 30 per cent survival rate.

The 30 per cent figure may even overestimate the true survival rate, said Jule, because it is based on published results, and failed reintroductions are less likely to be reported in the academic literature.

The experts found that in over half the cases humans were the direct cause of death; with shootings, poisonings and traffic accidents topping the bill. The studies also revealed that the captive animals were less resistant to diseases than their wild-born counterparts

The authors noted that the study highlights the need for reintroduction projects to be carefully assessed to ensure the best chances of success. They are now testing the effectiveness of pre-release techniques such as minimising human contact, creating more natural social groupings and improving hunting experience that may boost the rates of success.

Long-term monitoring

Long-term monitoring of released animals also needs to be increased, in order to determine their success over a number of years, added Jule.

“Since humans are typically the most likely cause of carnivore demise it comes as no surprise that we are again the most prevalent culprit preventing or reducing success of carnivore reintroductions,” commented Robert Beschta of Oregon State University in Corvallis, U.S., who has studied the effects of large carnivores on ecosystems.

“A heavy dose of public education needs to precede a carnivore reintroduction if they are to minimise subsequent human impacts,” he said.

Reintroducing captive animals back to their native habitats has been a central-plank of many zoo-managed conservation projects and notable successes have included re-establishing the golden lion tamarin in Brazil and the koala to areas of South Australia and Victoria.

Despite this, success rates for reintroductions of non-carnivorous animals also range from just 13 to 30 per cent, said Jule.


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