Floristic composition and ecological succession of macroalgae on reefs of Piedade Beach (PE, northeastern Brazil)

Abstract

The present study had the objective of evaluating the recovery, after non-natural perturbations, of algal communities at Piedade Beach, District of Jaboatão dos Guararapes, south coast of the Pernambuco State, northeastern Brazil. Algal percent cover was evaluated to follow the temporal variation and the relative recovery of disturbed communities by scraping 20x20 cm quadrats that were monitored for six months. Two sites were chosen horizontally in relation to the ocean. In Site 01 succession experiments were carried out in the community dominated by Solieria filiformis (Kütz.) P.W. Gabrielson and follow up was also carried out approximately every 15 days in recruitment quadrats and compared to the control plots. Site 02 was dominated by green foliose algae with evidence to Ulva. On this site the succession experiments were not carried out. In laboratory the collected macroalgae were identified to the species level, 44% were from the Phyllum Chlorophyta, 52% from the Phyllum Rhodophyta and 4% from the division Ochrophyta, 25 species were shown in 15 families and 9 orders. The species Ulva rigida C. Agardh stood out since it is the first register of this species at Piedade beach and second on the Pernambuco coast. The first sample, before the scraping, only registered the presence of green foliose algae assemblage (33.3%) and the red algae (44.6%), since they characterize the climax community of the environment. The opportunistic algae: - Ulva flexuosa (Wulfen) J. Agardh, U. flexuosa (Wulfen) J. Agardh subsp. flexuosa, U. fasciata Delile , U. lactuca L. e U. rigida were the first to settle in the studied community. The community recovery was partly reached because filamentous algae in the succession plots showed lower percentage cover than in the beginning of the experiment.

Key words: macroalgae, floristic composition, percentage cover, sandstone reefs, ecological succession.