National Park Service

South Florida/Caribbean I&M Network (SFCN)

Coral Reef Monitoring Status & Trends in SFCN Parks

Biscayne National Park Status & Trends

In 2012 the South Florida/Caribbean Network staff conducted annual coral reef community monitoring of index sites at Ball Buoy Reef and Amanda's Reef. These two sites now have 9 years of monitoring data. Data at both sites were collected using the Coral Reef Monitoring Protocol (which includes the HD video for benthic component cover), Diadema antillarum abundance, coral disease presence/type and measurements, and reef-depth water temperature co-located at each sample site. The 2013 data is not included in this report since monitoring was rescheduled due to the Government shutdown. In 2014, SFCN will continue to conduct annual coral reef index site monitoring. A BISC park wide marine benthic community assessment schedule is under development.

Trends in live stony coral cover at Ball Buoy and Amanda's Reef, BISC
Trends in live stony coral cover at Ball Buoy and Amanda's Reef, BISC.
Biscayne National Park (BISC) water temperature summary graph:  Graph shows water temperature data from the two index sites in BISC since 2003. The bleaching stress threshold of 30.5°C is shown.
Biscayne National Park (BISC) water temperature summary graph: Graph shows water temperature data from the two index sites in BISC since 2003. The bleaching stress threshold of 30.5°C is shown.
Number of days above theoretical bleaching threshhold temperature in Biscayne National Park
Number of days above theoretical bleaching threshhold temperature in Biscayne National Park.

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Buck Island Reef National Monument Status & Trends

In 2013 the South Florida/Caribbean Network staff conducted annual coral reef index site monitoring in BUIS (South Fore Reef and Western Spur-and-Groove). Data were collected using the Coral Reef Monitoring Protocol (which includes the HD video for benthic component cover), Diadema antillarum abundance, coral disease presence/type and measurements, and reef-depth water temperature co-located at each sample site. The BUIS sites have 12 and 14 years of sampling data respectively. In 2014, SFCN staff will continue to conduct annual coral reef index site monitoring.

Trends in live stony coral cover at Western Spur-and-groove and South Fore Reefs, BUIS.  Grey bars indicate coral bleaching/disease event of 2005 that continued into 2006 and the coral bleaching event in 2010. (Coral bleaching occurs when coral under stress lose their symbiotic algae and look white or "bleached.")
Trends in live stony coral cover at Western Spur-and-groove and South Fore Reefs, BUIS. Grey bars indicate coral bleaching/disease event of 2005 that continued into 2006 and the coral bleaching event in 2010. (Coral bleaching occurs when coral under stress lose their symbiotic algae and look white or "bleached.")
Changes in coral community composition and relative abundance at S. Fore  Reef (BUIS). Coral cover has doubled at this site since the dramatic die-off (2005-07). This increase is attributed to the increase by Agaricia and Porites species. Cover by the regionally abundant Montastraea annularis complex has not increased since its 44% decline in 2005-07.
Changes in coral community composition and relative abundance at S. Fore Reef (BUIS). Coral cover has doubled at this site since the dramatic die-off (2005-07). This increase is attributed to the increase by Agaricia and Porites species. Cover by the regionally abundant Montastraea annularis complex has not increased since its 44% decline in 2005-07.
Buck Island Reef National Monument (BUIS) water temperature summary graph:  Graph shows water temperature data from the two index sites in BUIS since 2002. The bleaching stress threshold of 29.5 °C is shown.
Buck Island Reef National Monument (BUIS) water temperature summary graph: Graph shows water temperature data from the two index sites in BUIS since 2002. The bleaching stress threshold of 29.5°C is shown.

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Dry Tortugas National Park Status and Trends

DRTO RNA Science Plan 5-year Report

A section called "Eight years of coral reef community monitoring: results from inside and outside the Research Natural Area at Dry Tortugas National Park" and a new benthic map were presented in the Implementing the Dry Tortugas National Park RNA Science Plan: The 5-year Report. This report presents results on interdisciplinary studies that focused on the performance efficacy of the no-take Research Natural Area (RNA).

Annual monitoring and site installation

SFCN staff monitored marine benthic communities during a 10 day cruise on the M/V Ft. Jefferson in June 2012. Data was collected on 13 of 18 extensive sites established for coral reef monitoring. Extensive sites were originally installed in FY08 (nine sites inside and nine outside of the newly established Research Natural Area [RNA]. Five extensive sites were not surveyed due to extremely low percent coral cover recorded in previous years (< 2%) which was below the initial pre-installation site estimate of >5% and monitoring such low coral cover sites are not the purpose of this protocol.

SFCN staff also conducted annual coral reef index site monitoring at Bird Key Reef which now completes 9 years of data. Coral monitoring was discontinued at the Bird Key North Index site (water temperature data still collected), in part because of its close proximity to the Bird Key Index site. This was also done to allow for an increased monitoring effort in habitat delineated in the 2010 DRTO Benthic Habitat Map; primarily in the northeast and southwest sections of DRTO (e.g., low and high relief spur-and-groove, reef terrace). SFCN revised its extensive site study design in FY12 to include these areas in the survey domain and to allow specific reporting of trends in the high coral cover Montastraea complex dominated reefs of Loggerhead Forest and an area named by staff as "Santa's Village". In Jeff Miller's words, these are "special places within special places" and require focused effort.

Field reconnaissance was conducted in March and June 2012 to determine the reef boundaries of Loggerhead Forest and Santa's Village Reefs using time-referenced photos, underwater video, and observations of benthos and depth with SCUBA. After establishing the geographical domain for each reef, SFCN staff established randomly selected sites within the reef domains (Figure below). An extensive-style site design (four cardinal transects; N, E, S, W) was chosen for these areas with consideration for the relative large size of these reefs and diving logistics. The Santa's Village Index site consists of three extensive-style coral monitoring sites (12 transects total). An additional three new extensive-style sites were also established within Loggerhead Forest, which complements the two existing sites previously established there (protocols and data collected as listed above). The new Loggerhead Forest Index site is comprised of five extensive-style sites (20 transects total).

Status and Trends

SFCN staff monitored marine benthic communities during a 10 day cruise on the M/V Ft. Jefferson in June 2013. Sampling was conducted at the index sites (Bird Key, Santa's Village, and Loggerhead Forest. Data was collected using the Coral Reef Monitoring Protocol (which includes the High Definition video for benthic component cover), Diadema antillarum abundance, coral disease presence/type and measurements, and reef-depth water temperature co-located at each sample site. Additionally, water temperature data was obtained from all the index sites. Coral reef monitoring was discontinued at the Bird Key North index site and at the I-33, I-63, O-12, O-27 and O-92 extensive sites; however, temperature will still be monitored at Bird Key North and I-33.

The amount of coral disease (white plague and yellow band) observed in these high coral cover sites is noteworthy. Despite the lack of historical monitoring data, the size, rugosity and complexity of these coral communities indicate a high likelihood of good conditions for reef growth and survival for the past several hundred years. With the introduction of SFCN monitoring in 2012–13 at these sites, the observations of large and abundant areas of active (and recent) mortality from coral disease is cause for grave concern. The ecological importance of these rare and complex coral communities as sources of coral larvae for reefs within DRTO and S. Florida are yet to be fully understood. These coral communities are very slow growing (~1–3 mm/yr.) and cannot sustain the level of mortality being experienced from coral disease.

Locations of the extensive-style index coral reef monitoring sites at Santa's Village Reef and Loggerhead Forrest in DRTO. (Loggerhead Forest sites I-5 and I-50 not displayed).
Locations of the extensive-style index coral reef monitoring sites at Santa's Village Reef and Loggerhead Forrest in DRTO. (Loggerhead Forest sites I-5 and I-50 not displayed).

Montastraea dominated reef terrace on the Loggerhead Forest index site (Photo credit: Rob Waara)
Montastraea dominated reef terrace on the Loggerhead Forest index site (Photo credit: Rob Waara).

Trends in live stony coral cover at select monitored reefs in DRTO
Trends in live stony coral cover at select monitored reefs in DRTO.
Dry Tortugas National Park (DRTO) water temperature summary graph for Bird Key
Dry Tortugas National Park (DRTO) water temperature summary graph for Bird Key.

Additional Water Temperature Findings

Temperature data from the DRTO index and extensive sites reveal that benthic resources are subject to a wide variance in thermal stress. In particular, temperature records from the extensive sites show cold-water events from the past three years, occuring between late April and early June, designated by red circles in the Figure below. The most severe recorded event occurred in June 2010, where several extensive sites were affected (Figure below). It is suspected that this cold-water anomaly is from upwelling, influenced by currents off the Tortugas Bank, along the northwestern edge of the park. During the cold-water events, sites I-50, I-05, and I-38 experienced the lowest temperatures, likely due to the proximity to Tortugas Bank and the comparatively deep nature of these three extensive sites.

Dry Tortugas National Park water temperature summary graph including all sites.  Graph shows water temperature data from the 18 index sites in DRTO since 2008.  The bleaching stress threshold of 30.5°C is shown.  The three red circles indicate cold-water events, occuring in late spring through early summer
Dry Tortugas National Park water temperature summary graph including all sites. Graph shows water temperature data from the 18 index sites in DRTO since 2008. The bleaching stress threshold of 30.5°C is shown. The three red circles indicate cold-water events, occuring in late spring through early summer.

A regional summary of in situ seawater temperature at SFCN parks reveals a substantially different thermal regime between the South Florida and Caribbean. Corals within the South Florida parks are subject to wide annual temperature variation, often >±10°, and consistent, annual excursions beyond the theoretical coral bleaching threshold (~30.5°C). The Virgin Island reefs experience a much smaller temperature range (~±4°C). Typically, they do not get as warm as the Florida reefs, with the exception of 2005, a year of extreme Caribbean heating, and record-breaking hurricane activity in South Florida. The reefs within the Virgin Islands consistently exceed their theoretical coral bleaching threshold (~29.5°) (Figure for VIIS below; 1998, 2001 and 2003–2012).

Comparison of mean daily temperatures at SFCN parks by region from summer 2004 through summer 2012.  US Virgin Island parks include VIIS and BUIS. S. Florida parks include BISC and DRTO
Comparison of mean daily temperatures at SFCN parks by region from summer 2004 through summer 2012. US Virgin Island parks include VIIS and BUIS. S. Florida parks include BISC and DRTO.

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Salt River Bay National Historical Park and Ecological Preserve Park Status and Trends

SFCN staff installed an index site consisting of 20 permanent transects for coral reef monitoring in Salt River Bay National Historic Park and Ecological Preserve (SARI) in April 2012 (Figure below). The transects were randomly distributed in three distinct areas: outer canyon east wall (4 transects), canyon west wall (4 transects), and a spur-and-groove area northwest of the canyon (12 transects). These areas were chosen because of relatively high coral cover, reef complexity, historical significance and were constrained to 33 m depth. Prior to site installation, ecological significance of these areas was confirmed by in situ field reconnaissance (time-referenced photos, underwater video, and observations of benthos and depth) by SFCN staff in February 2012.

Locations of the 20 transects comprising the SARI coral reef monitoring index site in three areas: outer canyon east wall (green), canyon west wall (orange), and spur-and-groove area northwest of the canyon (blue)
Locations of the 20 transects comprising the SARI coral reef monitoring index site in three areas: outer canyon east wall (green), canyon west wall (orange), and spur-and-groove area northwest of the canyon (blue).

This is the first year the SFCN has collected benthic data at the SARI index site (Figure below). Data will be collected annually using the Coral Reef Monitoring Protocol, which includes the High Definition video for benthic component cover, Diadema antillarum abundance, coral disease presence/type and measurements. Reef-depth water temperature data is also collected at two of the 20 transect locations in SARI.

Initial results from SARI coral reef monitoring index site
Initial results from SARI coral reef monitoring index site.

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Virgin Islands National Park Status and Trends

In 2012 the South Florida/Caribbean Network staff conducted annual coral reef index site monitoring in VIIS (Tektite Reef, Haulover Reef, Yawzi Reef, Mennebeck Reef, and Newfound Reef). The sites in VIIS have between 8–14 years of data.

Despite the passing of Tropical Storm Isaac which helped to lower thermal stress, mean daily temperatures exceeded the theoretical bleaching threshold (29.5°) on September 11–13 (Figure below), and remained above that level for the rest of the month. Coral bleaching was observed at the three VIIS sites monitored in September and October with Mennebeck Reef, sampled in October, showing the most severe bleaching (see Figure below). While monitoring revealed that bleaching became more severe through September into October 2012, no corals at any site experienced complete loss of pigment (correlating to severe thermal stress). However, nearly two-thirds of coral cover exhibited some level of bleaching at Mennebeck Reef, the last of the sites to be monitored.

With regards to overall trends, none of the sites have recovered from the 2005–2006 bleaching disease event. However Mennebeck, Tektite, and Yawzi reefs have shown small, but statistically significant, upward trends since 2007. No significant trend has been detected at either Haulover or Newfound Reef sites. No statistically significant effect was detected due to the 2010 bleaching event although graphically there appears to be a minor drop at some sites.

In 2013 SFCN will conduct annual coral reef index site monitoring at sites in VIIS.

Trends in live stony coral cover at index sites throughout VIIS. Grey bars indicate coral bleaching/disease event of 2005 that continued into 2006 and the coral bleaching event in 2010
Trends in live stony coral cover at index sites throughout VIIS. Grey bars indicate coral bleaching/disease event of 2005 that continued into 2006 and the coral bleaching event in 2010.

Virgin Islands National Park (VIIS) water temperature summary graph: Graph shows water temperature data from the six sites in VIIS since 1988. The bleaching stress threshold of 29.5°C is shown
Virgin Islands National Park (VIIS) water temperature summary graph: Graph shows water temperature data from the six sites in VIIS since 1988. The bleaching stress threshold of 29.5°C is shown.

The water temperature in 2012 for Virgin Islands National Park compared with 2005 (a significant bleaching year) and the 1990–2004 range of daily average temperatures for all sites. The bleaching stress threshold of 29.5°C is shown. Tropical Storm Isaac passed approximately 175 miles south of VIIS on August 29–30
The water temperature in 2012 for Virgin Islands National Park compared with 2005 (a significant bleaching year) and the 1990–2004 range of daily average temperatures for all sites. The bleaching stress threshold of 29.5°C is shown. Tropical Storm Isaac passed approximately 175 miles south of VIIS on August 29–30.

Comparison of bleaching severity (BL1-4) at three index sites monitoring during peak thermal stress in VIIS.  BL1=Bleaching Level 1 – complete loss of color signifying significant stress to the coral and significant loss of zooxanthellae.  BL4=Bleaching Level 4 – slight loss of color signifying relatively minor stress to coral and minimal loss of zooxanthellae. Non-bleached indicates normal coral pigment
Comparison of bleaching severity (BL1-4) at three index sites monitoring during peak thermal stress in VIIS. BL1=Bleaching Level 1 – complete loss of color signifying significant stress to the coral and significant loss of zooxanthellae. BL4=Bleaching Level 4 – slight loss of color signifying relatively minor stress to coral and minimal loss of zooxanthellae. Non-bleached indicates normal coral pigment.

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Last Updated: March 28, 2017 Contact Webmaster