Rat-free islands vital to keeping coral reefs healthy: study

SYDNEY, July 12 (Xinhua) -- A new international study, published on Thursday, has documented the devastating impact of rats that are having on birdlife and coral atolls.

A team of researchers from Australia, the United States and Britain compared the ocean's nitrogen levels surrounding a series uninhabited islands in the Chagos Archipelago, located in a remote part of the Indian Ocean.

"It's really a natural, quite a pristine setting where you've got six islands that have rats on them and then six right next door that don't have the rats," one of the paper's author Andrew Hoey from Australia's James Cook University told local media.

"So you couldn't really design the experiment much better."

The results show that birdlife plays a vital role in the health of corals because their droppings act to fertilize reefs and the sourrounding ecosystems.

But because rats prey on young birds and eat their eggs, the natural nutrient flow can be "disrupted."

In total, they found that seabird densities were 760 times higher on the islands which did not have rats and that translated into the production of 250 times more nitrogen.

"The key thing for seabirds is that they're travelling a fair way offshore and bringing in these oceanic sources of nutrient onto the islands," Hoey said.

In Australia, native birds and wildlife have been ravaged by a number introduced species, including rats and authors of the paper conclude that eradicating island rat infestations should be a priority for environmental conservationists.

"There's growing evidence, like down on Macquarie Island right down near Antarctica, where they've had successful eradication of things like rats and foxes." Hoey said.

"If you can do it, and you can specifically target rats and get rid of them without harming the rest of the ecosystem, then great."

[ Editor: WPY ]


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