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Northwestern Hawaiian Islands Study Reveals Fragility of World’s Coral

NCEAS Scientists Benjamin Halpern and Kimberly Selkoe



By Gail Gallessich

A new study by researchers from the National Center for Ecological Analysis and Synthesis (NCEAS) sheds light on how threats to the world’s endangered coral reef ecosystems can be more effectively managed.
In a recent issue of the journal Coral Reefs, lead authors Kimberly A. Selkoe and Benjamin S. Halpernexplain how their maps of the Northwestern Hawaiian Islands (NWHI) –– a vast area stretching over 1,200 miles –– can be used to make informed decisions about protecting the world’s fragile reefs.
Coral reef ecosystems are at risk due to the direct and indirect effects of human activities. This study was designed to help natural resource managers make decisions on issues such as surveillance priorities, granting of permits for use, and determining which areas to monitor for climate change effects.
“Our maps of cumulative human impact are a powerful tool for synthesizing and visualizing the state of the oceans,” said first author Selkoe, who is also affiliated with Hawaii Institute of Marine Biology at the University of Hawaii. “The maps can aid in strategically zoning uses of oceans in an informed way that maximizes commercial and societal benefits while minimizing further cumulative impact.”
“President (George W.) Bush declared the Northwestern Hawaiian Islands a National Monument in 2006, in part because it is one of the last places in the oceans that has not been heavily altered by human activities,” said Halpern. “Our maps of cumulative human impact on these islands show that, despite their extreme isolation, humans are already significantly impacting this special place, and that many of the key threats, such as those associated with climate change, are not mitigated with Monument designation. We must continue to act to protect these islands and coral atolls if we hope to preserve them for future generations.”
The authors studied 14 threats specific to NWHI, all generated by humans. They included alien species, bottom fishing, lobster trap fishing, ship-based pollution, ship strike risks, marine debris, research diving, research equipment installation, and wildlife sacrifice for research. Human-induced climate change threats were also studied, including increased ultraviolet radiation, seawater acidification, the number of warm ocean temperature anomalies relevant to disease outbreaks and coral bleaching, and sea level rise.
The authors note that this analysis can serve as a case study for other areas and managers who are interested in mapping region-specific cumulative human impacts and in making assessments.