Assessing Reef Resilience in the Northern Mariana Islands

NOAA scientists in the Commonwealth of the Northern Marians Islands developed new and innovative techniques to help resource managers rank coral reef resilience.

The Commonwealth of the Northern Mariana Islands is home to diverse coral reef ecosystems that provide residents with jobs, food, and recreational activities. They also protect communities from powerful storms.

Reefs in the region experienced widespread bleaching in both 2013 and 2014. The assessment of reef resilience, or the ability of a coral reef to either resist a stressful event or recover from it, is the first step to targeted, effective management of coral reefs in the face of climate change.

Scientists evaluated the potential resilience of 78 coral reef sites off the coasts of the commonwealth's more populated islands of Saipan, Tinian/Aguijan, and Rota. They looked at several indicators, including:

• Bleaching resistance,
• Coral diversity,
• Coral recruitment,
• Microalgae cover,
• Presence of herbivorous marine life,
• Sea surface temperature, and
• The exchange of coral and fish larvae between islands.

Lastly, the team looked at the exposure of the study sites to manmade stressors, like sediment and nutrient loading.

Their assessment revealed that Saipan, one of the most populated islands in the archipelago, is home to the commonwealth's most resilient reef sites in the study. Sites off of Rota ranked low in terms of resilience. The data also indicate that the presence of herbivores, coral recruitment, and the exchange of coral and fish larvae between islands are key drivers of resilience.

The results will help officials implement resilience-based management strategies on the ground and in the water across the commonwealth. This approach, which creates direct links between the science and management of coral reefs, will have global relevance as we move toward managing for resilience.

Partners in this effort include:

NOAA Coral Reef Conservation Program, U.S. Geological Survey, University of Guam, CNMI Bureau of Environmental and Coastal Quality, and many others. Special thanks are extended to Congressman Gregorio Kilili Camacho Sablan from the Northern Mariana Islands.