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Acroporid Coral Status & Conservation
Photo Credit: SEFSC
Photo Credit: SEFSC
Figure shows the demise of an elkhorn coral colony over time, most of the mortality was caused by the corallivorous snail (Coralliophila abbreviata)
Photo Credit: SEFSC
Acropora palmata (elkhorn coral) is one of the dominant framework builders on Caribbean reefs. Its branching morphology and tendency to form dense mono-specific stands naturally provides shelter to a variety of fish and other ecologically and economically important reef organisms, including Diadema antillarum (Long-spined sea urchin) and Panulirus argus (Caribbean spiny lobster).
Acropora cervicornis (staghorn coral) has cylindrical branches and thrives in moderate wave energy reef zones including the fore reef "buttress" zone, back reef and patch reefs. Its dense branching structure and fast growth rate is important in the sediment and rubble binding processes that form reef framework.
Since the 1970s, acroporid species in the Caribbean have experienced extreme and accelerating declines estimated at 90-98% throughout their range. Much of the decline has been attributed to widespread white-band disease but the overall loss is thought to have been exacerbated by more frequent and intense bleaching events, hurricanes as well as other diseases and anthropogenic effects.
Loss of these structurally complex framework builders has diminished zonation and thus species diversity on Caribbean reefs. The severe and protracted population decline led NOAA Fisheries to designate the listing of these species as "threatened" under the U.S. Endangered Species Act in May 2006.
The project is centered on long term demographic monitoring of Acropora palmata to collect basic population data such as the numbers and sizes of individual colonies as well as recruitment (birth rates) and mortality (death rates) so that changes to the population can be documented and a future trajectory can be estimated. Surveys also asses the condition of the population by documenting disease, predation and other aspects that may hinder recovery. The condition assessments allow us to understand the relative impacts of these stressors so that managers can prioritize conservation efforts and resources. These data can used for demographic modeling by our collaborators and provide insight on the future trajectory of the population under various disturbance and proactive conservation regimes (see Vardi & Williams ).
The current monitoring activities began in 2004 in the upper Florida Keys and in 2006 comparable monitoring was initiated in Curaçao. A detailed protocol was released in 2006 to encourage partners to conduct surveys using comparable methods so that data could be more easily compared. In 2010, NMFS Division of Protected Resources funded the Florida Wildlife Conservation Commission to expand comparable demographic monitoring of elkhorn coral throughout south Florida, the Dry Tortugas, the USVI and Puerto Rico.
- Williams DE, Miller MW (2010) Drivers of population decline in Acropora palmata in the Florida Keys National Marine Sanctuary Linking Science to Management: A Conference and Workshop on the Florida Keys Marine Ecosystem, Duck Key
- Williams DE, Miller MW, Kramer KL (2008) Recruitment failure in Florida Keys Acropora palmata, a threatened Caribbean coral Coral Reefs 27(3): 697-705
- Gleason ACR, Lirman D, Williams DE, et al. (2007) Documenting hurricane impacts on coral reefs using two dimensional video-mosaic technology Marine Ecology 28: 1-5
- Williams DE, Miller MW (2006) Importance of disease & predation to the growth & survivorship of juvenile Acropora palmata & Acropora cervicornis: a demographic approach. Proceedings of the 10th International Coral Reef Symposium 1: 1096-1104
- Williams DE, Miller MW, Kramer KL (2006) Demographic monitoring protocols for threatened Caribbean Acropora spp. corals. NOAA Technical Memorandum NMFS-SEFSC-543
- Williams DE, Miller MW (2005) Coral disease outbreak: pattern, prevalence and transmission in Acropora cervicornis Marine Ecology Progress Series 301: 119-128
- Miller MW, Bourque AS, Bohnsack JA (2002) An analysis of the loss of acroporid corals at Looe Key, Florida, USA: 1983-2000 Coral Reefs 21(2): 179-182
- Benthic Ecosystem Assessment & Research
- Acropora Corals
» Demographic Monitoring
» Acropora Disease
- Coral Early Life History and Climate Change Impacts
- Aquarius Coral Restoration/Resilience Experiments (ACRRE)
- Reef and Fisheries Assessment of Navassa Island National Wildlife Refuge
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