Factors driving seed bank diversity in wetlands of a large river floodplain

Abstract

Soil seed banks serve as reservoirs of taxonomic and genetic diversity and can buffer the effect of perturbations on plant communities, and thus are critical for community resilience. We studied the relationship of seed bank abundance and richness with different hydrological attributes, evaluated beta diversity patterns among wetlands in the Middle Paraná River floodplain, and experimentally explored soil seed bank germination after a drought period. Seed abundance was positively related to drought intensity and, along with richness, negatively related to drought and flood frequency. Turnover and balanced variation in abundance greatly contributed to the total beta diversity probably associated with the environmental heterogeneity of the floodplain; nestedness had a lower contribution probably associated with different dispersal abilities of species. Germination behavior varied between rooted and free-floating plants. In conclusion, the soil seed banks studied are highly variable among habitats; drought and flood frequency, and drought intensity are related with the seed banks abundance and richness; and the germination responses after a drought phase differ among broad ecological groups of wetland plants.