Coral reef in French Polynesia, rebounded from catastrophic damage in 2010. (Photo credit: Peter Edmunds)

Amidst dire reports about the health of the world’s coral reefs, a team of 18 researchers, including several with ties to the Hawaiʻi Institute for Marine Biology (HIMB) at the University of Hawaiʻi at Mānoa School of Ocean and Earth Science and Technology, have found coral reef “oases” that provide hope all is not lost for these beautiful ecosystems.

The team, led by Peter Edmunds, California State University, Northridge marine biologist; Ruth Gates, HIMB director; and Ilsa Kuffner, a U.S. Geological Survey (USGS) research marine biologist, developed a framework for identifying specific coral reefs in the world’s oceans where corals appear to be thriving. They hope their findings, published in the June 18 issue of the Journal of Applied Ecology, will encourage further study into why these communities of corals are surviving while so many more are not, and inspire efforts to identify similar oases in other ecosystems.

“Over the last 12 to 24 months, damage to coral reefs worldwide has appeared at an alarming rate, with deaths driven by the most recent El Niño, compounded by climate change induced ocean warming,” said Edmunds. “But there are still places that are doing surprisingly well. These coral reef oases focus the attention on environments and communities that can help enhance coral conservation efforts.”

“Coral reefs are in rapid, global decline,” added Dan Thornhill, program director in the National Science Foundation’s Division of Ocean Sciences, which funded a substantial portion of the ecological investigations upon which this compilation study is based. “This timely and much-needed paper identifies coral reefs that are doing better than most, places that may provide a refuge against the worst effects of climate change.”

Broad view of coral reef ecosystems

Rebounded coral reef in Moorea, French Polynesia. (Photo credit: Peter J Edmunds)

The 18 researchers have extensive knowledge about the conditions of coral reefs in the Pacific and the Caribbean. With support from the USGS John Wesley Powell Center for Analysis and Synthesis, they developed a framework for identifying oases within four coral reef regions that have been studied for decades, in many cases by many of their own team members. Their framework considers the health of coral communities, how often they had been disturbed, and how long they had remained in a healthy or unhealthy state.

The researcher team identified 38 oases locations categorized as either “escape,” “resist” or “rebound” oases. Escape oases are coral communities that have been able to avoid disasters such as bleaching, invasions from coral-eating sea stars or the wrath of hurricanes. Resist oases are coral communities that appear hardy and resist environmental challenges. Rebound oases are coral communities that have suffered damage like many other reefs, but have rebounded to a coral-dominated state.

Remarkable capacity for recovery

HIMB‘s Gates said she has been “blown away by the capacity of the some badly damaged reefs in Hawaiʻi to recover from past disturbances. There are areas in Hawaiʻi which are remarkable example of oases.”

Given the 38 oases the researchers have identified, Edmunds said it is logical to assume that there are more coral oases in the rest of the world’s oceans. ”We are optimistic that our coral reef oases are signs of hope for the future, rather than the last gasp of a dying ecosystem,” he said.

With this study, the co-authors provide conservationists and policy makers with a tool to identify areas that warrant stronger protection or specific management strategies, as these intact ecosystems may be able to catalyze broader ecosystem recovery.

Also on the research team are UH graduate student Beth Lenz and UH alumna Hollie Putnam.

—By Marcie Grabowski