Meeting Abstract
Global declines in cover of reef building scleractinian corals on tropical reefs have occurred over the last few decades, and these losses have been caused by a diversity of anthropogenic effects including global climate change. In response, there are large research efforts to study the patterns and causes of the changes and to develop mitigation measures. However, these efforts are usually focused on scleractinian corals, while the impacts on other taxa, such as non reef building octocorals in the Caribbean, are less well understood. Since octocorals can provide significant 3-dimensional habitat, they can be considered ecosystem engineers that affect biodiversity. In light of their potential importance, we compared trajectories of change in scleractinian and octocoral communities on two reefs in St. John, US Virgin Islands, that have been studied for 27 years. Patterns of changing abundance of these two groups differed noticeably, where in one case scleractinians suffered a dramatic decline, while octocorals often resisted stressors like hurricanes better. Furthermore, it appears that octocorals recover faster from stressors. Our results show that octocorals can maintain habitat structure where scleractinians suffer losses, and this raises the question of their role in future reef ecosystems. It is likely that despite general reef degradation in the Caribbean, octocorals might be able to maintain ecosystem services that rely on 3-dimensional structure, including functioning as nurseries for coastal fishes and enhancing biodiversity.
