Marine protected areas (MPAs), regions of the sea closed to harmful human activities, are effective in safeguarding coral ecosystems, which are often heavily used by coastal communities. But as new research shows, when MPAs are next to areas of high human activity, some of the benefits are lost—even in areas where fishers and others follow all the rules.
The vast majority of MPAs are coastal, and coastal MPAs are often smaller and more fragmented than those far out at sea. The median area of coastal MPAs is less than 10 square kilometers, while large offshore MPAs, such as the Marae Moana ocean sanctuary around the Cook Islands, cover nearly two million square kilometers. These small pockets of protection do help the coastal ecosystem, yet a team of researchers led by Nicholas Graham, a marine ecologist at Lancaster University in England, found that around areas of high human activity, MPAs do virtually nothing to protect top predators.
Graham and his colleagues applied a concept called “gravity” to develop a new way to measure human impacts on coral reef ecosystems. “Gravity is a proxy for human pressure,” Graham says.
Photo: Mark Conlin/NMFS/Wikimedia Commons