Resumo
Hydroids are broadly reported in epiphytic associations from different localities showing marked seasonal cycles. Studies have shown that the factors behind these seasonal differences in hydroid richness and abundance may vary significantly according to the area of study. Seasonal differences in epiphytic hydroid cover and richness were evaluated in a Sargassum cymosum C. Agardh bed from Lázaro beach, at Ubatuba, Brazil. Significant seasonal differences were found in total hydroid cover, but not in species richness. Hydroid cover increased from March (early fall) to February (summer). Most of this pattern was caused by two of the most abundant species: Aglaophenia latecarinata Allman, 1877 and Orthopyxis sargassicola (Nutting, 1915). Hydroid richness seems to be related to S. cymosum size but not directly to its biomass. The seasonal differences in hydroid richness and algal cover are shown to be similar to other works in the study region and in the Mediterranean. Seasonal recruitment of hydroid species larvae may be responsible for their seasonal differences in algal cover, although other factors such as grazing activity of gammarid amphipods on S. cymosum must be taken into account.
Resumo
Hydroids are broadly reported in epiphytic associations from different localities showing marked seasonal cycles. Studies have shown that the factors behind these seasonal differences in hydroid richness and abundance may vary significantly according to the area of study. Seasonal differences in epiphytic hydroid cover and richness were evaluated in a Sargassum cymosum C. Agardh bed from Lázaro beach, at Ubatuba, Brazil. Significant seasonal differences were found in total hydroid cover, but not in species richness. Hydroid cover increased from March (early fall) to February (summer). Most of this pattern was caused by two of the most abundant species: Aglaophenia latecarinata Allman, 1877 and Orthopyxis sargassicola (Nutting, 1915). Hydroid richness seems to be related to S. cymosum size but not directly to its biomass. The seasonal differences in hydroid richness and algal cover are shown to be similar to other works in the study region and in the Mediterranean. Seasonal recruitment of hydroid species larvae may be responsible for their seasonal differences in algal cover, although other factors such as grazing activity of gammarid amphipods on S. cymosum must be taken into account.
Resumo
Hydroids are broadly reported in epiphytic associations from different localities showing marked seasonal cycles. Studies have shown that the factors behind these seasonal differences in hydroid richness and abundance may vary significantly according to the area of study. Seasonal differences in epiphytic hydroid cover and richness were evaluated in a Sargassum cymosum C. Agardh bed from Lázaro beach, at Ubatuba, Brazil. Significant seasonal differences were found in total hydroid cover, but not in species richness. Hydroid cover increased from March (early fall) to February (summer). Most of this pattern was caused by two of the most abundant species: Aglaophenia latecarinata Allman, 1877 and Orthopyxis sargassicola (Nutting, 1915). Hydroid richness seems to be related to S. cymosum size but not directly to its biomass. The seasonal differences in hydroid richness and algal cover are shown to be similar to other works in the study region and in the Mediterranean. Seasonal recruitment of hydroid species larvae may be responsible for their seasonal differences in algal cover, although other factors such as grazing activity of gammarid amphipods on S. cymosum must be taken into account.
Resumo
The presence of epiphytic organisms can influence the distribution of macroinvertebrates associated with algae. This study evaluated the influence of Sargassum epibiosis by epiphytic algae and hydroids on the occurrence of caprellid amphipods. The sampling was carried out on Sargassum beds of Ubatuba beaches, northern coast of São Paulo state, in October 2006. The presence of epiphytic algae and hydroids on Sargassum fronds was evaluated using five cover categories. Epiphytic algae showed significant cover differences among beaches, while hydroids occurrence was more uniform, without significant differences on the levels of epibiosis. None of the caprellid species identified showed differences in its density among beaches. Despite the epibiosis variation, it was not a determinant factor in the distribution of caprellid species.
Resumo
The presence of epiphytic organisms can influence the distribution of macroinvertebrates associated with algae. This study evaluated the influence of Sargassum epibiosis by epiphytic algae and hydroids on the occurrence of caprellid amphipods. The sampling was carried out on Sargassum beds of Ubatuba beaches, northern coast of São Paulo state, in October 2006. The presence of epiphytic algae and hydroids on Sargassum fronds was evaluated using five cover categories. Epiphytic algae showed significant cover differences among beaches, while hydroids occurrence was more uniform, without significant differences on the levels of epibiosis. None of the caprellid species identified showed differences in its density among beaches. Despite the epibiosis variation, it was not a determinant factor in the distribution of caprellid species.