Dried aquatic macrophytes are floating egg banks and potential dispersal vectors of ostracods (Crustacea) from pleuston communities

In aquatic ecosystems, such as Neotropical floodplains, it is common to find dried aquatic macrophytes along the margins of various environments (e.g. lakes and rivers) during the dry season. Here, we evaluate the potential of dried Eichhornia crassipes as a dispersal vector of ostracod resting eggs by assessing the abundance, richness and beta diversity of the dormant associated fauna. We test two hypotheses: (1) that the roots of E. crassipes shelter and disperse ostracod resting eggs and (2) that the abundance, richness and beta diversity of dormant assemblages will increase over the incubation time after re-hydration. Dried E. crassipes from floodplain lakes were hydrated with distilled water. The microcosms were kept in germinating chambers with controlled temperature and photoperiod during 147 days. A total of 397 ostracods representing seven species hatched from the resting eggs attached to dried macrophyte roots. An increase in richness and a decrease in abundance were observed over the weeks, although these trends were not significant. However, the beta diversity increased significantly over the incubation time. Our results show that the complex root systems of E. crassipes have the potential for storage and dispersal of ostracod resting eggs