Data Management Plan

Declines in the health of coral reef ecosystems lead scientists to search for factors that support reef resilience: the ability of reefs to resist environmental stress and recover when they have been impacted, and to maintain key ecosystem functions throughout. Scientists have identified eleven measurable factors that affect the resilience of coral reefs. Reef resilience factors include characteristics of the coral assemblage, populations of fish that live on the reef, land-based influences, and sea surface temperature variability. NOAA Pacific Islands Fisheries Science Center (PIFSC) Ecosystem Sciences Division (ESD) used these factors to quantitatively assess the resilience potential of reefs around Tutuila and Aunu‘u Islands in American Samoa.

Locations of monitoring surveys conducted by ESD from 2010 to 2016 were used to designate study zones. The monitoring surveys provided data to evaluate biological/ecological resilience factors, and external data sources were used to inform physical and environmental factors not directly measured by ESD. Data for each metric was compiled, normalized, and averaged to produce a composite resilience score for each of zone. The primary resilience analysis includes all 11 metrics for 10 study zones around Tutuila and Aunu'u, excluding Taema Bank. The secondary resilience analysis includes the 8 metrics available for 11 study zones around Tutuila and Aunu'u, including Taema Bank.

The information provided with this analysis includes the individual datasets for the 11 metrics used in the analysis (data tables), the survey sites and study zones (data tables), and the resilience scores resulting from the analysis (data tables and maps).

Islands of Tutuila and Aunu'u, American Samoa

Lineage Statement:
The principal analytical task of this project was to calculate eleven metrics of "reef resilience" as identified by McClanahan et al. (2012). These metrics account for various aspects of the coral reef ecosystem, and are derived from several data streams, as described in the process steps.

Process Steps:

• The first task was to identify and define zones of interest, hereafter known as study zones. Eleven study zones were delineated for the present project. Four of these zones reflect broad geographic regions (i.e. Northeast, Northwest, Southeast, Southwest) that have been used to organize ecological surveys conducted by the ESD under the National Coral Reef Monitoring Program based on broadly similar habitat and exposure to wave and weather conditions. Several smaller zones of interest were then identified that had been the subject of focused survey effort by the ESD during previous projects, providing geographically dense data to evaluate the resilience potential for each individual zone: Taema Bank had suffered severe impacts due to predation on corals by crown-of-thorns seastars; Aunu‘u East, Aunu‘u West, Fagamalo, and Fagatele are marine protected areas (MPAs); and Faga‘alu Bay and Vatia Bay were the subject of previous studies by ESD on impacts of land-based sources of pollution (LBSP) (Vargas-Ángel and Schumacher In Review). (Citation: Vargas-Angel, B., B.D. Schumacher. (2018). Baseline Surveys for Coral Reef Community Structure and Demographics in Vatia and Faga'alu Bay, American Samoa NOAA Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-18-002, 38 p.)
• The basis of the pollution metric is a watershed health index based on analysis of the American Samoa Environmental Protection Agency (Tuitele 2016). We used ArcGIS to combine this information by merging watersheds associated with each georegion and calculating a weighted mean WHI by area. (Citation: Tuitele C, et al. TERRITORY OF AMERICAN SAMOA INTEGRATED WATER QUALITY MONITORING AND ASSESSMENT REPORT 2016)
• The sedimentation metric is based on precipitation that falls on the watersheds associated with each georegion. A "precipitation index" was derived based on interpolated rainfall information from the NOAA National Weather Service (https://hdsc.nws.noaa.gov/hdsc/pfds/meta/na14_vol5_as_grid_metadata.xml). Rainfall was scaled by the coastline of each georegion.
• The herbivore biomass metric was derived from data from NOAA Ecosystem Sciences Division Rapid Ecological Assessment (REA) fish surveys. Mean herbivore biomass for each zone, as well as all subsequently described metrics based on data from REA surveys, were calculated based on a weighted average of reef area in three depth zones (0-6 meters, 6-18 meters, 18-30 meters). (Citation: Ayotte, P., K. McCoy, A. Heenan, I. Williams, and J. Zamzow. 2015. Coral reef ecosystem program standard operating procedures: data collection for rapid ecological assessment fish surveys. Pacific Islands Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Honolulu, HI 96818-5007. Pacific Islands Fish. Sci. Cent. Admin. Rep. H-15-07, 33p. doi:10.7289/V5SN06ZT)
• The macroalgal cover metric was derived from analysis of digital images of the benthos (photoquadrats) from NOAA Ecosystem Sciences Division Rapid Ecological Assessment (REA) fish and coral surveys. (Citation: Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.)
• Metrics for coral diversity, coral recruitment, physical impacts to coral, and disease prevalence were calculated from data gathered by NOAA Ecosystem Sciences Division Rapid Ecological Assessment (REA) benthic surveys.
• The bleaching resistance metric was calculated based on the percent corals of a given species found in georegions, scaled by their sensitivity to bleaching as determined by observations of corals during a bleaching event.
• The fishing pressure metric was derived from multiple data sources. The proximity of human population was the primary driver. Census data was used to estimate mean population within 10 kilometers of reef in each georegion. No-take marine protected areas were assumed to not have fishing activity. Commericial fishing trips to a region were also used to create an index that was averaged with human population. These were scaled by reef area and averaged.
• The Sea Surface Temperature (SST) variability metric was derived from Pathfinder v5.2 ~4 kilometer (1/24 degrees) daily SST data for the period 1985-2012, provided by the Group for High Resolution Sea Surface Temperature (GHRSST) and the U.S. National Oceanographic Data Center. The Pathfinder project was supported in part by a grant from the NOAA Climate Data Record (CDR) Program for satellites. Scott Heron created derived data sets based on these data under a NOAA Coral Reef Conservation Program (CRCP) grant (Heron-786), and these derived data sets were used as the basis of the SST variability metric. Based on discussions with Heron, the number of significant thermal events (defined as a period where a reef area experienced 4 consecutive degree heating weeks) and the interannual variability (standard deviation) of the climactically warmest month were combined to calculate the SST variability metric. Additional information about thermal history products is available at the Coral Reef Watch website (http://coralreefwatch.noaa.gov/satellite/thermal_history/th_index.php). (Citation: Heron SF, et al. "Warming Trends and Bleaching Stress of the World’s Coral Reefs 1985-2012." Scientific Reports 6 (2016): 38402.)

With some datasets, two different individuals generated summary statistics that were verified against each other. In other cases, the analysis was run two different ways or two different times and results were cross-checked. "Sanity checks" were also performed to evaluate if the results make sense and are logical.

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

NOAA IRC and NOAA Fisheries ITS resources and assets.