A Long-Term Study of Reef Coral Dynamics in the Florida Keys

Williams Meier, Ouida Diane

During the course of this study six different offshore ("barrier") reef sites were monitored throughout the Florida Keys, USA. The primary monitoring method we relied upon was that of permanently marked, relocatable photostation quadrats. Though this method was extremely labor-intensive both in site set up and data analysis it offered a high degree of precision, the ability to return to exactly the same underwater sites repeatedly, and the ability to track individual colonies over time. The permanent establishment of these sites, the record of data we have collected, the use of multiple sampling methods, and the incidental occurrence of not one but two natural disasters in one set of sites (following three years of collecting baseline data) has rendered these sites very valuable indeed. It is rewarding to know that the information, experience, and insights we have gained through this study are already being integrated into a much larger scale coral reef monitoring project recently initiated by EPA in the Florida Keys National Marine Sanctuary. After the initial five- to seven- year monitoring period of our original study, we have made progress toward a characterization of Floridian reefs and measurement of the status and trends of coral reef communities and populations. This information should be useful in the evaluation of progress toward protecting and restoring the natural resources of the south Florida marine environment. We developed a set of hypotheses to guide our thinking, though these hypotheses are only truly testable at a much larger spatial scale than that at which we were realistically able to operate. The null hypothesis was that the coral communities are at dynamic equilibrium (no net change in percent cover or species richness over certain time scales). Alternative hypotheses include: (1) overall reef decline in percent cover, species richness, and other measurable community parameters, (2) overall reef increase in measurable community parameters, (3) significant changes observed in individual reefs with no overall change on a landscape scale decreases in one location balanced by increases elsewhere), or (4) changes are linked to specific regions of the landscape.