Staghorn survey and bioassays to test for improved condition in thickets to guide restoration efforts - Final Report for Endangered Species Research Permit (NOAA) STX026-12

Background:

While the degradation of Caribbean coral reefs has ignited international efforts to restore corals to denuded reefs, current methods for outplanting corals are largely lacking scientifically-based management protocols. In recent years, over 32 restoration efforts in nine Caribbean countries have been established in attempt to repopulate reefs with nursery-reared corals (Young-Lahiff et al 2012). These nurseries are focusing their restoration efforts on the staghorn coral, Acropora cervicornis, a "critically endangered" species on the global IUCN Red List. National Oceanic and Atmospheric Association (NOAA) is also required to formulate an A. cervicornis recovery plan under the Endangered Species Act, yet progress has been hindered by knowledge gaps on where and how to out-plant nursery-reared colonies to maximize restoration success. To align with the stated needs of the NOAA Acropora recovery plan, this research aims to develop and disseminate scientifically-informed guidance for staghorn coral outplanting to enhance the habitat and ecosystem function (NOAA 2009).

An opportunity to uncover the role of this coral species in reef ecosystem function is offered studying the handful of extant and/or newly rebounding populations of A. cervicornis in the Caribbean. This research is aimed to track and monitor these naturally occurring A. cervicornis populations of various densities to refine targets of recovery and health for this keystone species. Specifically, we aim to improve restoration efforts by determining optimal colony density, size, and configuration for outplanting colonies. Studying naturally-recovering populations as a template, this study can direct coral restoration to mimic the success of these natural populations and thereby improve restoration success.

Based on our 2012 monitoring of several extant populations of A. cervicornis in the Caribbean (Huntington a nd Miller in prep), we hypothesized that A. cervicornis growth rates and tissue condition are enhanced when very dense spatial configurations (i.e. Thickets¿) of coral are achieved. Our research from 2013 focused on observational studies and an experimental bioassay to discern a mechanism to account for this greater coral condition, which we hypothesized was from the indirect enrichment of the coral from organic nutrients excreted form fish sheltering within the thicket. To test this hypothesis, we used an experimental bioassay study in two Caribbean locations: Dry Tortugas National Park (DRTO), Florida and St. Thomas, United States Virgin Islands (USVI) to determine if coral condition was enhanced when transplanted to a thicket site versus a low density A. cervicornis site. While DRTO contains both high density spatial configurations of A. cervicornis and high abundances of schooling reef fishes, schooling fishes are rarer in the A. cervicornis populations in St. Thomas. By performing the same bioassay experiment in each location we can isolate the influence of reef fishes to facilitate higher condition in A. cervicornis.

Title : Staghorn survey and bioassays to test for improved condition in thickets to guide restoration efforts

Personal Author(s) : Huntington, Brittany;Miller, Margaret W. (Margaret Wohlenberg);Richter, Lee, 1950-;

Corporate Authors(s) : United States, National Marine Fisheries Service,;Southeast Fisheries Science Center (U.S.);United States, National Oceanic and Atmospheric Administration,;Coral Reef Conservation Program (U.S.);

Published Date : 2013

URL : https://repository.library.noaa.gov/view/noaa/12981