Killing rats could save coral reefs, say scientists

The much-maligned rat is not a creature that many associate with coral reefs.

However, scientists studying tropical island reefs say that animals directly threaten the survival of these ecosystems.

A team working on the Chagos Islands in the Indian Ocean found invasive rats. islands are a "big problem" for coral reefs

Rats decimate seabird populations, decimating in turn the volume of bird droppings – a natural coral fertilizer

The results are published in Nature .

Scientists now advocate the eradication of rats from all islands to protect these delicate marine habitats.

The Chagos Archipelago provided a large-scale natural laboratory to answer this question; Although the islands are uninhabited by humans, some of them are now home to invasive rats, brought by ships and wrecks. Other islands remained free of rats.

"The islands with and without rats are like chalk and cheese," said Professor Nick Graham of Lancaster University

"The ratless islands are full of birds, they are noisy, the sky is full and they smell – because the guano that birds deposit on the island is very pungent.

"If you walk on an island with rats, there is no seabirds. "

This study reveals that rats disrupt a healthy ecosystem that relies on the excrement of seabirds, which fertilize the reefs surrounding the island.

On Pest Free Islands of rats, seabirds, especially lunatics, frigates, shearwaters and terns When they return to the island, they deposit rich nutrients in the fish they feed on.

"These nutrients are leached on the reef, "said Professor Graham

.The team was able to follow the penny "We also found that reef fish adjacent to islands with seabirds grew faster and were larger for their age than fish on reefs beside reefs. "Coral reefs cover less than 0.1 percent of the ocean's surface, but the number of fish living on rat-free reefs is significantly higher than that of the" rattenées "islands

. About a third of the ocean's biodiversity.

"Coral reefs are also extremely endangered," Graham said. "All those who care about extinctions and biodiversity need to worry about the future of coral reefs."

The reefs and their abundance of marine life provide livelihoods for millions of people around the world. The decline of coral reefs

This team of researchers advocates for rat eradication projects on islands around the world

"Coral reef systems are in crisis due to climate change," said the Professor Graham. They are desperately trying to find ways to improve the resilience of coral reefs and enable them to cope with climate change.

"It's one of the clearest examples up here, where the eradication of rats will cause an increase in the number of seabirds – the coral reef. "

-BBC