Banco de sementes de uma floresta secundária amazônica dominada por Vismia

Abstract

The floristic compostion of a secondary forest dominated by Vismia in central Amazonia was studied and compared to the composition of the seed bank in the soil. The area contained 20 tree species, with Vismia being the dominant genus in importance value, relative density, and basal area. The seed bank collected from the area exhibited 17 species that germinated, all pioneers, of which half were herbaceous and half were woody. In general, the composition of the seed bank was characteristic of successional stages with a strong influence from the abandoned pasture, the presence of pioneer species, and a large number of herbs and grasses. Two genera, Goupia and Laetia, were absent from the bank, although adult individuals were in the canopy. The three genera over-represented in the seed bank, relative to the canopy, were Cecropia, Bellucia and Trema, whose seeds probably arrived after the development of the canopy of Vismia. In field plots where the canopy was removed, germination mirrored the composition of the established vegetation in the area without the presence of new species exclusive to the seed bank. Thus, the return to primary forest will be delayed and depend on the proximity of seed sources as well as the presence of dispersers to contribute a diverse seed rain.