Abundance and composition of juvenile scleractinian corals on a fringing reef (Little Reef) off San Andres Island, Colombian Caribbean

Abstract

Colombian Caribbean reefs have deteriorated significantly over the last three decades. Coral recruitment is an important demographic process that determines the replenishment of populations and the natural potential for recovery of reef ecosystems after perturbations. We studied the composition and abundance of juvenile corals on a fringing reef (Little Reef) off San Andres Island, Colombia, using 1 m² quadrats (N = 33) spread randomly on the reef. We surveyed a total of 190 juvenile corals belonging to seven families and 15 species, with a total density of 5.75 ± 3.47 (mean ± SD) juveniles m⁻². The population of juvenile corals was dominated by species of the genera Favia, Agaricia and Porites (85.8%), while the adult population was dominated by Diploria, Acropora and Orbicella (78.4%). Most (71.6%) juveniles were between 1.1 and 2.0 cm. The most abundant species was Favia fragum (67 individuals), while Agaricia agaricites was the most frequently occurring (26.9%), covering the highest percentage (76.9%) of the substrate and having the largest Importance Value Index (44.6%). The community of juvenile corals on Little Reef was dominated by species that brood planulae while the adult community was dominated by species that spawn gametes. Furthermore, the two most abundant juvenile coral species had negatively skewed size–frequency distributions, indicating low recent recruitment. This study provides a demographic baseline for monitoring future changes in recruitment patterns.

Key words:

• Caribbean Sea
• juveniles
• recruitment
• San Andres Island
• scleractinian corals

Acknowledgements

Special thanks to Vanessa Izquierdo, Raúl Neira and the students from the Coral Reef Ecology course (2007), from the Universidad del Valle, for their help during fieldwork. Much appreciation is due to Christine Schelten, who provided data on the growth rates of juvenile corals and to Luisa Dueñas, Tomás López-Londoño, Claudia Villamil and Diego Gil-Agudelo who provided data on coral recruitment, Francesca Benzoni who advised us on taxonomical changes and to members of the Coral Reef Ecology Research Group at Universidad del Valle. Two anonymous reviewers also improved this manuscript. CORALINA granted access to coral reefs in the Seaflower Biosphere Reserve and the Universidad del Valle supported this study.

Editorial responsibility: Franz Uiblein