Cristina Falcão, Maria Teresa Menezes de Széchy
Changes in shallow phytobenthic assemblages in southeastern Brazil, following the replacement of Sargassum vulgare (Phaeophyta) by Caulerpa scalpelliformis (Chlorophyta)
The structure of shallow sublittoral phytobenthic assemblages from Ilha Grande Bay, Rio de Janeiro, southeastern Brazil, was described to evaluate the effect of the presence of Caulerpa scalpelliformis on the dominant species, Sargassum vulgare. The canopy cover of macroscopic organisms was analyzed monthly or less frequently on rocky substrata from Baleia Beach (impact location, where C. scalpelliformis appeared) and from two reference locations (without C. scalpelliformis), during the periods September 1993 to May 1995 and October 2001 to September 2003, using the point sampling method (n=5 random quadrats). At the impact location, S. vulgare was dominant from September 1993 to September 2001, when C. scalpelliformis appeared on the rocky substratum beneath S. vulgare. In a few months, the cover of S. vulgare declined dramatically and C. scalpelliformis became dominant on the rocky and sandy substrata until the end of the study. Over the same period, S. vulgare was dominant at the reference locations. Multivariate community analysis revealed significant changes in the macroalgal community structure following the appearance of C. scalpelliformis. The replacement of S. vulgare by C. scalpelliformis suggests the competitive superiority of C. scalpelliformis under sheltered conditions. This is the first record of this pantropical macroalga in the warm temperate region of the Brazilian coast.
Botanica Marina, Walter de Gruyter
Print ISSN: 0006-8055
Volume: 48, 07/2005
Pages: 208 - 217
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