As the state of the world’s coral reefs appear to be getting worse with every passing year, an international team of scientists studying the reefs of tropical islands have come up with an unusual idea for how to help them: Kill all the nearby rats.
Studying the Chagos Archipelago in the Indian Ocean, the researchers found a surprising link between invasive rats on the island, the local seabird populations, and the health of the nearby reefs. They realized that the issue of introduced rats decimating the local bird populations was having an unforeseen effect on the health of the reefs.
It is estimated that invasive predators like rats, which feed on bird eggs and chicks, have hugely impacted bird populations on about 90 percent of the world’s tropical islands, but this is the first time rats have been identified as the enemies of reefs too.
“Seabirds are crucial to these kinds of islands because they are able to fly to highly productive areas of open ocean to feed. They then return to their island homes where they roost and breed, depositing guano – or bird droppings – on the soil,” Professor Nick Graham of Lancaster Universtiy explained in a statement.
“This guano is rich in the nutrients, nitrogen and phosphorus. Until now, we didn’t know to what extent this made a difference to adjacent coral reefs.”
The Chagos Islands were the perfect place to carry out this study as 18 of the 55 islands are miraculously rat-free while the others have been overrun with black rats. This meant they could directly compare the effects of the rodents on both ecosystems and draw substantial conclusions, publishing the dramatic results in Nature.