Overview




time-series of coral photos

Coral Image Viewer

For more information about the map below, and the sites specifically, click here.

This project focuses on the long-term, benthic community dynamics of coral reefs along the south shore of St John, US Virgin Islands. Additional sites are periodically sampled around St. John and St Thomas. The project began in 1987 and consists of permanently marked areas that are photographed annually for benthic community structure, areas that are censused annually for the density, growth, and survivorship of juvenile corals, and sites at which the recruitment of stony corals is measured. In 2011, 11 sites were selected around St. John and St. Thomas with the objectives of sampling: (1) reefs that are in similar habitats to those reefs forming the core time series for this project, (2) over the largest possible spatial scale within St John and St Thomas, and (3) north and south shores of both islands. Surveys take place at ≤ 14 m depth, and the majority of sites are on the south shore of St. John between Cabritte Point (east), and White Point (west). This project is complimentary to reef monitoring conducted by the Virgin Islands National Park, and is led by Dr. Peter Edmunds from California State University, Northridge. The project currently is funded through the US National Science Foundation through the their programs in Long-Term Research in Environmental Biology and Biological Oceanography.

The objective of this study is to describe temporal variation in coral reef community structure, first, to elucidate patterns of change in key components of the benthic communities, and second, to test for processes that drive the changes observed.  The core of the project relies on digital images that have been recorded at least annually since December 1987, and are available here as a photographic archive for further analysis. The photographs describe areas of reef either 1 x 1 m or 0.5 x 0.5m in size, with multiple images: (a) from a reef (Tektite) at 14 m depth starting in 1987, (b) from a reef at 9 m depth (Yawzi Point) starting in 1987, (c) from up to 6 sites (most recently described as “Pooled Random Sites” [PRS]) that were selected at random in 1992 and have been recorded annually thereafter, and (d) from 11 landscape-scale sites selected in 2011 and sampled every ~4 y (most recently 2015). In addition to the photographs, the density, growth, and survivorship of juvenile corals has been recorded at multiple sites since 1994, and coral recruitment has been measured since 2007.

Starting in 2014, a new initiative (in collaboration with Drs. Howie Lasker and Lorenzo Bramanti) was added to provide an “octocoral overlay” to existing sites with the objective of exploring covariation in community structure of stony and soft corals. The octocoral project currently is funded for 3-4 y (2014-2017), but it is anticipated that it will grow into a multi-decadal record based on in-water surveys and retrospective analysis of photoquadrats.

time-series of coral photos

Coral Image Viewer