Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Effects of the alien coral Tubastraea tagusensis on native coral assemblages in a southwestern Atlantic coral reef.

Abstract

The alien coral Tubastraea spp. has invaded Atlantic coral reefs since 1940s, but their effects on native coral assemblages are poorly understood. In this study the effects on coral assemblage structure and tissue mortality in native competitors by alien coral were investigated. We compared native coral cover in zones with and without T. tagusensis and evaluated the mortality of native coral species in natural encounters with T. tagusensis. Additionally, we evaluated the effects of contact with this invader on two native corals, Siderastrea stellata and Montastraea cavernosa, using a manipulative experiment. Multivariate analyses detected significant differences between coral assemblages in invaded and non-invaded zones. In the invaded zone, we observed greater cover of T. tagusensis on reef walls (34.9±4.2%) than on reef tops (18.5±4.1%). Madracis decactis and Mussismilia hispida were significantly less abundant in invaded zone than in non-invaded zones at the reef walls. Manipulative experiments showed a significant increase in tissue mortality of S. stellata (3.2±1.4 cm2) after 60 days of contact with T. tagusensis and no effects on M. cavernosa after 90 days of contact. In natural encounters, 52 and 0.1% of the S. stellata and M. cavernosa colonies, respectively, showed tissue mortality. These results indicate that competitive interactions with native competitors are important to understand alien coral establishment on coral reef. Our study documents the negative effects of the alien coral on coral reef assemblages and reinforces the urgent need for monitoring and management actions to control the expansion of this invader on Brazilian reefs.