The influence of the carnivorous macrophyte Utricularia foliosa on the taxonomic structure of the periphytic algae community

Thiago Rodrigues dos Santos, Carla Ferragut, Carlod Eduardo de Mattos Bicudo

Resumo


Aim: Present study evaluates the seasonal taxonomic structure of the periphytic algal community on modified leaf and stem of the Utricularia foliosa in a tropical shallow reservoir. Methods: To evaluate the influence of the substrate, the periphyton structure on artificial and natural substrates was compared. Monospecific stands of U. foliosa were selected. Water and periphyton sampling were performed inside the U. foliosa stands in the fall (April/2010), winter (July/2010), spring (November/2010) and summer (February/2011). Nylon thread was used as the artificial substrate. Based on algal biovolume, the algal taxonomic structure was evaluated through life forms, species richness, diversity and species composition. Results: The life forms and species richness were different between substrate types and climatic seasons. Species diversity was significantly different only among seasons. Species composition indicated that five species were associated with the natural substrate and only one with the artificial substrate. Regarding the seasonal variation, two species were strongly associated with the limnological conditions of the summer and one with the winter. Our findings showed low species composition similarity between natural and artificial substrates. Life forms, species richness and diversity responded weakly to the substrate types. In opposition, species-level taxonomic classification responded clearly to the substrate type. Conclusions: It was evident that the species-level taxonomic classification and life forms respond to the substrate types, but seasonality seems to influence significance of the periphyton responses. We conclude that the species composition of periphytic algae on artificial substrate was very low representative of the composition on Utricularia foliosa, which provided environmental favorable conditions for the development of periphyton.


Palavras-chave


perifíton; algas; reservatório

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