MEPS 330:101-111 (2007)  -  doi:10.3354/meps330101

ABSTRACT: Two species of azooxanthellate coral, Tubastraea coccinea Lesson, 1829 and T. tagusensis Wells, 1982, are alien to the rocky shores of Brazil. The influence of 5 substratum types—wood, granite, concrete, steel and ceramic tiles—on their recruitment was investigated experimentally. On the artificial plates, mean density of T. tagusensis varied from 202 to 512 colonies m^–2 and that of T. coccinea varied from 187 to 233 colonies m^–2 after 17 mo. The density of Tubastraea spp. recruits was similar to those found in coral reef environments worldwide. A strong coupling between local adult density and recruitment density was found at a scale of <1 m. Substratum type and species were important in determining density and size of the recruits of the alien corals. The density of T. tagusensis on cement was higher than on ceramic tiles or steel, but T. coccinea density did not differ significantly among substratum types. The size of T. tagusensis recruits did not differ among materials, but T. coccinea recruits were smaller on steel than on granite or cement. The density of recruits also depended on the density of adults on the reef. No differences in cover or biomass of the associated biological community were observed among substrata. T. coccinea and T. tagusensis did not exhibit very strong selection for specific substrata and ably recruited to all materials. Their opportunistic behavior and high fecundity indicate that these are generalist species in terms of substratum utilization, which accounts for how they can successfully disperse to and invade areas consisting of different substratum materials.

KEY WORDS: Brazil · Invasive species · Scleractinia · Substratum · Tubastraea