Diaspore bank of aquatic macrophytes maintaining species diversity in a Neotropical pond/Banco de diasporos de macrofitas aquaticas para a manutencao da diversidade das especies em uma lagoa neotropical

The diaspore bank is an important component of biological diversity acting mainly as storage and source of diaspores, which also indicate dynamics and patterns of maintenance of plant diversity. We tested the hypothesis that the diaspore bank would be the responsible factor for the maintenance of the aquatic plant species, used two techniques to evaluate the diaspore bank: seedling emergence and direct counting of field samples. Density and richness of the diaspore bank were correlated with plant cover of the aquatic macrophyte communities and also with the euphotic zone radiation in different phases of the hydrological cycle. The diaspore bank is a key factor in maintenance of aquatic macrophyte assemblages in this pond. Nymphaea amazonum was one of the dominant species in the pond and presented temporally peaks of plant cover. Furthermore, depth allowed induction of germination of stored diaspores. Therefore, the diaspore bank may predict which species colonizes a site when environmental characteristics are favorable and allows inferring which processes are linked to changes in structure of aquatic macrophyte assemblages. These mechanisms are the means for recovery of macrophyte species under natural disturbances, represented by water level oscillations in floodplains. Keywords: aquatic plant, plant ecology, seed bank, wetland. O banco de diasporos e um componente importante da diversidade biologica atuando principalmente como armazenamento e fonte de diasporos, que tambem indicam a dinamica e os padroes de manutencao da diversidade vegetal. Testamos a hipotese de que o banco de diasporos seria o fator responsavel pela manutencao das especies de plantas aquaticas, utilizando duas tecnicas para avaliar o banco diasporo: emergencia das plantulas e contagem direta de amostras de campo. Densidade e riqueza do banco de diasporos foram correlacionadas com cobertura vegetal das comunidades de macrofitas aquaticas e tambem com a radiacao da zona eufotica em diferentes fases do ciclo hidrologico. O banco de diasporos e um fator chave na manutencao das assembleias de macrofitas aquaticas nesta lagoa. Nymphaea amazonum foi uma das especies dominantes na lagoa temporalmente, apresentou picos de cobertura vegetal. Alem disso, a profundidade permitiu a inducao da germinacao de diasporos armazenados. Portanto, o banco de diasporo e um preditor de quais especies colonizarao um local quando as caracteristicas ambientais sao favoraveis e permite inferir que os processos e