August 13, 2002

Little Barrier Island Rat Eradication Good News For Conservation

The Royal Forest and Bird Protection Society is delighted by the announcement that the Department of Conservation is gearing up to eradicate rats from Little Barrier, or Hauturu, Island in the Hauraki Gulf.

"Hauturu is one of New Zealand's premier Nature Reserves. It contains one of the largest tracts of relatively unmodified native forest in the Auckland Region, including some of the few areas in New Zealand that have never been logged," says Forest and Bird's northern field officer, Sarah Gibbs. "Eradicating rats from Hauturu will improve its conservation value even more. It will mean tuatara and other populations that can not survive in the presence of rats will be able to flourish."

"The benefits to wildlife on other islands where rats have been eradicated, such as Tiritiri Matangi and Kapiti, have been enormous", says Ms Gibbs. "The technology to eradicate rats from an island the size of Hauturu has been available for almost a decade. Rat eradication should not be delayed any longer".

All species of rats have had a devastating impact on New Zealand's ecology. "Rats got onto Big South Cape Island in the 1980s. We lost several species in the space of just a few years and the island's vegetation was devastated," says Ms Gibbs.

Fortunately, New Zealanders are world leaders in conservation-related pest eradications on offshore islands. Rats have already been eradicated from several key conservation islands around New Zealand, including Tiritiri Matangi in the Hauraki Gulf.

Ms Gibbs says that it is important the next Minister of Conservation continue the excellent work carried out by Sandra Lee while she held the post. The Society would like to see that the new Minister ensures the Department develops a prioritised plan to systematically eradicate rats and other pests and predators from all suitable offshore islands.

"It is only on predator-free offshore islands that some species can survive," says Ms Gibbs. "Rat eradication on Hauturu and other offshore islands can only have positive outcomes."

NOTES FOR JOURNALISTS: 1. Kiore, or Pacific rat, are widely distributed throughout the Pacific and are thought to be the third most common rat in the world. As New Zealand has no native land-mammals (except native bats), it is widely assumed that kiore were transported to New Zealand in the waka of early Maori settlers. 2. Kiore are omnivorous. As a result, a number of native New Zealand species are not able to co-exist in the presence of kiore over the long term. A notable species in relation to Hauturu is tuatara, whose eggs lay unguarded in soft soil for over a year before hatching. Tuataras are thought to have evolved before the dinosaurs, and New Zealand is the only country in the world to have anything resembling them. Young 'fingerling' tuatara are slow growing and vulnerable to rats, including kiore, and other predators for a number of years. By killing most or all tuatara eggs and young, rats have wiped out tuatara on mainland New Zealand in the same way as stoats and other predators are currently decimating kiwi populations. 3. Several adult tuatara have been found on Hauturu. These are currently being bred in captivity, but could be safely released back into the wild if a rat eradication on Hauturu was successful.

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