Abstract
The barrier reef ecosystem of SE Florida provides many valuable services including shoreline protection, tourism and recreational services, fisheries and employment. Unfortunately, 80% of Caribbean coral cover has been lost over the past 30 years due to disease outbreaks, bleaching, and other anthropogenic stressors. The loss of live coral cover also reduces net reef accretion rates, and may lead to net erosion of reefs if cover drops below 10%.Without continued reef growth, sea-level rise is projected to decrease the ability of reefs to provide services such as coastline protection.When determining the health of the reef ecosystem, indicators are needed to measure its ability to provide services, differentiate natural versus anthropogenic impacts and evaluate the effectiveness of current management practices.
Since live coral cover is a widely used indicator across monitoring programs and is a good evaluator of long-term condition and structure, % live coral cover (LCC) was extrapolated across the entire Florida Keys reef tract from the reef-monitoring database collected by the Florida Reef Resilience Program (FRRP, 2005-2013), which comprises>1700sites, that represent all sub regions and reef zones of the Florida Reef Tract (FRT). The report-card responses are as follows: (1) <5 %LCC may result in reef erosion; (2) 5-10 %LCC may be able to remain stable; and (3) >10 %LCC may be able to maintain reef accretionary properties. In all sub regions, the fore reef zone(outermost barrier reefs) had<10 % LCC (82%-Upper Keys; 97%-Middle Keys; 68%-Lower Keys; 42%-Dry Tortugas),which may challenge the persistence of these valuable ecosystems. Mid-channel and offshore patch reefs, across the FRT, showed the greatest % LCC values, with a large proportion (42%-98%) falling with the “green” coral cover bin, which could prove valuable for management and mitigation efforts. The % LCC index of the FRT can help document the current reef condition and structure that can be integrated into the Coastal Resilience wave toolkit, ultimately providing Florida’s policymakers, scientists and the public with a decision-support tool to help reduce the ecological and socio-economic costs of sea-level rise and other coastal hazards. Increased awareness of these hazards will help improve statewide conservation and restoration efforts.