MEPS 323:107-117 (2006)  -  doi:10.3354/meps323107

Inhibition of coral recruitment by macroalgae and cyanobacteria

Ilsa B. Kuffner1,*, Linda J. Walters2, Mikel A. Becerro3, Valerie J. Paul3, Raphael Ritson-Williams3, Kevin S. Beach4

1US Geological Survey, Center for Coastal & Watershed Studies, 600 4th Street South, St. Petersburg, Florida 33701, USA
2University of Central Florida, Department of Biology, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA
3Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Fort Pierce, Florida 34949, USA
4University of Tampa, Department of Biology, 401 W Kennedy Boulevard, Tampa, Florida 33606, USA

ABSTRACT: Coral recruitment is a key process in the maintenance and recovery of coral reef ecosystems. While intense competition between coral and algae is often assumed on reefs that have undergone phase shifts from coral to algal dominance, data examining the competitive interactions involved, particularly during the larval and immediate post-settlement stage, are scarce. Using a series of field and outdoor seawater table experiments, we tested the hypothesis that common species of macroalgae and cyanobacteria inhibit coral recruitment. We examined the effects of Lyngbya spp., Dictyota spp., Lobophora variegata (J. V. Lamouroux) Womersley, and Chondrophycus poiteaui (J. V. Lamouroux) Nam (formerly Laurencia poiteaui) on the recruitment success of Porites astreoides larvae. All species but C. poiteaui caused either recruitment inhibition or avoidance behavior in P. astreoides larvae, while L. confervoides and D. menstrualis significantly increased mortality rates of P. astreoides recruits. We also tested the effect of some of these macrophytes on larvae of the gorgonian octocoral Briareum asbestinum. Exposure to Lyngbya majuscula reduced survival and recruitment in the octocoral larvae. Our results provide evidence that algae and cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. On reefs experiencing phase shifts or temporary algal blooms, the restocking of adult coral populations may be slowed due to recruitment inhibition, thereby perpetuating reduced coral cover and limiting coral community recovery.


KEY WORDS: Allelopathy · Coral–algae interactions · Dictyota spp. · Lyngbya spp. · Phase shift


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