Marine Important Bird and Biodiversity Areas in the Chagos Archipelago

Summary Seabirds are declining globally and one of the most threatened groups birds. To halt or reverse this decline they need protection both on land at sea, requiring site-based conservation initiatives based seabird abundance diversity. The Important Bird Biodiversity Area (IBA) programme is a method identifying important places for birds agreed standardised criteria thresholds. However, while great strides have been made terrestrial sites, at-sea identification lacking. Chagos Archipelago, central Indian Ocean, supports four IBAs (tIBAs) two proposed marine (mIBAs). mIBAs seaward extensions to breeding colonies outdated information and, other types mIBA not explored. Here, we review extension using up-to-date status distribution use global positioning system (GPS) tracking from Red-footed Booby Sula sula – widely distributed seabirds archipelago identify any pelagic mIBAs. We demonstrate that due overlapping boundaries colony areas importance there single in Ocean lays entirely within Archipelago Marine Protected (MPA). Covering 62,379 km 2 it constitutes ~10% MPA if designated, would become 11 th largest world 4 Ocean. Our research strengthens evidence benefits large-scale MPAs predators provides scientific foundation stone biodiversity hotspot