Abstract Summary
Staghorn coral, Acropora cervicornis, is a threatened species that has declined more than 90% throughout the Caribbean since the late 1970s due to mortality from disease, hurricanes, bleaching, and predation. Outplanting of nursery-reared corals has become an established technique to enhance A. cervicornis populations. A growing body of literature documents encouraging results of restoration efforts, but most of these studies have only fate-tracked outplanted colonies for one or two years. During 2017, we revisited A. cervicornis restoration sites established during 2012 as part of an effort supported by the American Recovery and Reinvestment Act (ARRA). These sites offered a unique opportunity to evaluate the longer-term fate of A. cervicornis restoration efforts and evaluate potential factors that influence the success of these sites. However, fate tracking A. cervicornis colonies long-term is challenging as individual colonies readily fragment. Consequently, we did not attempt to fate track individual colonies as has been commonly done in short-term surveys, opting to estimate total A. cervicornis biomass by surveying the entire restoration site. We paired these surveys with surveys of benthic flora and fauna and characterized the physical structure of the sites to evaluate how these factors potentially affected site-related differences in A. cervicornis biomass. Hurricane Irma prevented the completion of this study as originally conceived. However, the A. cervicornis surveys we completed revealed substantial variation in coral biomass among the sites. Biomass had increased considerably at two Dry Tortugas sites and at one middle Keys site compared to two lower Keys sites and other middle Keys sites. A post-Irma survey of A. cervicornis biomass at those sites we had previously surveyed found considerable differences in survival. The middle and lower keys sites closest to the storm were heavily impacted, but the two sites in the Dry Tortugas had comparatively minor loss of A. cervicornis biomass.
