Comunidades macrofaunais bênticas associadas às algas de deriva e à grama marinha Halodule wrightii Ascherson na Ilha do Japonês, Cabo Frio, RJ

• Autor(a) principal: Silva, Amanda Ferreira da
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/5867
• topic: Drift algae; Seagrasses; Associated macrofauna; Density; Richness; Diversity; Community structure; Preservation; Algas de deriva; Gramas marinhas; Macrofauna associada; Densidade. Diversidade; Riqueza; Estruturação de comunidades; Preservação; Alga - Cabo Frio (RJ); Angiosperma - Cabo Frio (RJ); Diversidade de espécies - Cabo Frio (RJ); Interação animal - Planta; CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA

Extensive submerged meadows formed by seagrasses are an important habitat of the coast, where ecological interactions among different species of the submerged vegetation, benthic invertebrates and fish occur. The seagrasses and drift algae are known as marine macrophytes and, since they often can be found occupying the same substrate, they make a viable coexistence, providing oxygen, food, protection, shelter, besides breeding and grazing sites for the animals associated with these meadows. Samples of drift algae and H. wrightii were collected, along fixed 50 meter transects parallel to the Ilha do Japonês, so as to analyze the relationships between the species of marine macrophytes and the associated macrofauna, compare both communities and assess the structure of the local benthic macrofaunal community. Transects were allocated according to the position of the seagrass bed. It was found that shoot density and biomass of seagrasses did not explain the variation in drift algae biomass, species richness and diversity (Simpson index). The constant movement of the drift algae along the seagrass bed makes the algae homogenize and occupy different places by chance on the meadow, many of these places with low biomass of H. wrigthii, due to the high variability on the distribution of this species in the study area. The descriptors of the seagrassdid not have positive relations with its associated fauna either. Macrobenthos associated with the seagrasses was denser, richer and more diverse than the macrobenthic community associated with the drift algae. The mollusks Anomalocardia flexuosa, Cerithium atratum, Ostrea sp., Tellina lineata and Divalinga quadrissulcata dominated the environment of seagrass. The greater structural complexity of drift algae provided a protected habitat more attractive for the detritivores Pagurus criniticornic, Cymadusa filosa and Batea catharinensis. Malacofauna associated with algae was not abundant, but an important record was a new occurrence of the invasive bivalve Myoforceps aristatus, drilling a shell of Ostrea sp. The relationships among the descriptors of the algae biomass were confirmed to most of the descriptors of its associated fauna. Linear relations between marine macrophytes and its total macrobenthic community followed the same pattern as drift algae linear relationships. Cluster and MDS analysis showed that the local macrobenthic communities are structured according to the taxa of the most dominant associated organisms influenced by the type of the basibiont vegetation (drift algae or seagrasses). The present study considers the importance of more protective measures at the place for the preservation and maintenance of Ilha do Japonês ecosystem, RJ, Brasil