PRECHT, WILLIAM F.¹ and RICHARD B. ARONSON^2
1Law Engineering and Environmental Services, Inc., Miami Lakes, FL
²Dauphin Island Sea Lab, Dauphin Island, AL

Abstract: Combining Ecological and Paleoecological Methodologies to Decipher "Change" in Holocene Reef Communities

Coral reefs of the Caribbean have been in a state of flux for the past two decades. Among these changes has been the near elimination of the dominant coral species at intermediate depths, Acropora cervicornis (staghorn coral). Whether this transition is natural or the result of human disturbances is a topic of torrid debate. To address this issue, we must ask the question "Did episodes of reef degradation occur in the past, before the era of human interference, or is the current state of coral reefs unique to our time?" Assessing the novelty of the recent changes requires a multidisciplinary approach on multiple scales of space and time. However, the ecosystem in question must lend themselves readily to simultaneous interpretation at these multiple scales. Because coral reefs are both geologic and biologic entities, it should be possible to observe the effects of various disturbances in ecological time, detect historical changes in the paleoecological record, and deduce the multi-scale processes behind those patterns. To that end, we have undertaken a combined approach to deciphering the Holocene history of lagoonal reef complexes in Belize. There, catastrophic mortality of staghorn populations during the 1980's was documented using standard ecological reef monitoring techniques. This population collapse left a clear signal in the sedimentary record of these reefs. Therefore, the sedimentary record is the obvious place to look for the signals of previous occurrences. Subsurface investigation of these reefs showed that the recent collapse of staghorn populations throughout Belize is without precedent in at least the last few millennia. The novelty of this signal suggests that the current state of the Belizean reefs was produced by a combination of factors unique to our times. If these Belizean reefs are representative of the Caribbean as a whole, the possibility of an anthropogenic origin can not be discounted and warrants further study.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas