Informing coral reef management decisions at four US National Parks in the Pacific using long-term monitoring data

Effective management of coral reefs is challenging because of local and global stressors. Robust monitoring data are critical to managing these resources. Between 2006 and 2008, the Pacific Island Network Inventory and Monitoring Program of the U.S. National Park Service implemented monitoring protocols at four national parks in Hawai'i (Kaloko-Honokohau National Historical Park [KAHO], Kalaupapa National Historical Park [KALA]), Guam (War in the Pacific National Historical Park [WAPA]), and American Samoa (National Park of American Samoa [NPSA]). Benthic marine community, marine fish, and land-based surface and groundwater quality monitoring protocols used a split-panel sampling design to collect data on ecosystem "vital signs" and processes. Vital signs included coral species richness, percent coverage of benthic community types, fish abundance and biomass, rugosity, and a suite of surface and groundwater quality parameters. Data on key processes included top-down (e.g., fish trophic structure, bleaching, and disease) and bottom-up (e.g., coral larval settlement, turbidity, pH, temperature, nitrogen, phosphorus, salinity, groundwater levels) controls. The importance of these monitoring data is highlighted in four case studies that described how the information was used to manage a diverse array of issues at the parks. First, coral reef areas vulnerable to Acanthaster planci (crown-of-thorns sea star) outbreaks at NPSA and WAPA were identified to determine whether, and where, to focus culling efforts. Second, data were used at KALA to delineate zones with high fish biomass that were sensitive to fishing activities and warranted increased management. Third, coral settlement data at KALA identified sensitive regions within the park. Fourth, land-based surface water quality and groundwater dynamics monitoring data at KAHO were used to support management actions that mitigate land-based threats to park coral reefs. Advantages of the monitoring program included the split-panel sampling design, which provided a more complete picture of the resources with statistically robust data, and the efficacy of colocating and co-visiting sites for multiple protocols. The case studies demonstrated the usefulness of these data in the short term. In the long term, these data will continue to yield significant information about ecosystem responses to anthropogenic impacts and natural events, vital to park planning processes.