RUI: Long-Term Coral Reef Dynamics in the US Virgin Islands: 1987-2008

The University Corporation, Northridge, Northridge CA

Investigators

Abstract

Long-term coral reef dynamics in the USVI: 1987-2008 PI - Peter J. Edmunds Institution -- California State University Northridge Contact -- peter.edmunds@csun.edu This proposal focuses on coral reefs in the United States Virgin Islands (USVI), specifically extending an existing long-term study of coral reef community structure into its 22nd year and addressing four hypotheses addressing the mechanisms responsible for recent and ongoing changes in these systems. The analysis of the community structure entails documenting the relative abundance of live coral and algae on the sea floor, and quantifying the birth, death and growth rates of individual colonies of ecologically important species. To gain insight into the underlying causes of change, experiments will be conducted and existing data analyzed in order to: (i) identify the mechanisms relating coral success to their potential to reproduce and replace themselves, (ii) determine the importance of high temperature in killing coral recruits, (iii) gauge how the relative abundance of coral colonies of ecologically important sizes - namely large (i.e., old) colonies - has been changed by recent disturbances, and (iv) develop the capacity to forecast what the reefs of tomorrow will look like, and which species will dominate the communities. Close integration of this project with the VI National Park provides clear channels of communication through which the results can be directed in order to be effective components of the decision making process concerning the management of coral reef resources. To achieve the goals of this study, NSF support through the LTREB program will be used to complete a five-year analysis of coral reefs in St. John (USVI) that have been studied continuously by this investigator since 1987. Reefs in this location represent a resource of profound importance to the United States because they occur in a pristine location that is protected within a National Park and the international system of Biosphere Reserves. Because of this protection, changes on these reefs are more likely to reflect the "natural" dynamics of marine communities within this region rather than local effects attributed to urbanization and other human-induced effects. In other words, the reefs of St. John provide a unique reference site against which the effects of human impacts in more disturbed locations (for example, the Florida Keys and Hawaii) can be gauged. The merits of this project lie in the context, longevity and productivity of the existing study that provides an empirical justification to continue the research, as well as a framework within which meaningful hypotheses can be developed. Completion of this phase of the work will create one of the longest quantitative histories with annual resolution of a Caribbean reef, and by addressing mechanistic questions substantial advances will be made in understanding the causes and consequences of recent changes in coral reef community structure.