Nitrogen from bird guano is linked to more productive reef ecosystems
When invasive rats chow down on island seabirds, coral reefs suffer.
Researchers studied islands with and without the rodents in the Chagos Archipelago in the Indian Ocean. On rat-free isles, there were on average 1,243 birds per hectare compared with about two birds per hectare on rat-infested islands, the team found. And these rodentless islands had healthier coral reef ecosystems. The secret: Bird poop, naturally rich in nitrogen, washes into the ocean and helps keep reefs productive, the scientists report in the July 12 Nature.
“We’re essentially linking three ecosystems in this study,” says study coauthor Nick Graham, an ecologist at Lancaster University in England. The rats affect the seabirds, which affect the reefs.
Introduced by humans to the Chagos Archipelago in the late 18th century, rats have since devastated native seabird populations, including red-footed