Octocoral Forests: Distribution, Abundance, and Species Richness in Cuban Coral Reefs

Abstract

Octocorals provide multiple ecosystem services in coral reefs. Currently, in tropical western Atlantic reefs, the ecological condition of stony coral communities continues to decline; however, octocoral abundance is increasing at several locations throughout the region. The structure of octocoral communities was evaluated in Cuban reefs and was compared with that in the western Atlantic. We used 1 m2 quadrats to count colony numbers by species between 2001--2005 and 2008--2017 at 189 sampling sites. With 55 species, the octocoral richness in Cuban reefs constitutes one of the highest in this region. Among areas sampled during 2001--2005, the best ecological conditions for octocoral communities were found in Gardens of the Queen and Coco Key; here, octocorals had the greatest richness, diversity, and density. Among areas sampled during 2008--2017, the best ecological conditions for octocoral communities were in Colorados, Sabana-Camagüey, Canarreos, Artemisa, Mayabeque, and Havana (except in four highly polluted sites), where they showed the greatest richness and density. Antillogorgia americana and Eunicea flexuosa had wide distributions in Cuban reefs, except at some sites under the chronic influence of discharges from polluted watersheds in Havana. At those sites, the richness, diversity, and density of octocorals decreased, and their species composition changed toward more tolerant taxa to pollution and sedimentation.