Factors driving seed dispersal in a Neotropical river-floodplain system

FERNÁNDEZ, FLORENCIA FACELLI; SCHNEIDER, BERENICE; ZILLI, FLORENCIA

ACTA BOTANICA BRASILICA

SOC BOTANICA BRASIL

Año: 2019 vol. 33 p. 465 - 473

0102-3306

Dispersal is a key process affecting the diversity of natural communities. We addressed hydrochory of wetland plantseeds in the Middle Paraná River floodplain. We first studied seed dispersal by drifting macrophytes in the ParanáRiver main channel (MC), in a high discharge secondary channel (HD) and in two low discharge channels (LD) duringan extraordinary flood. We then experimentally analyzed the effect of standing (SW) and moving water (MW) onseed buoyancy of different plant communities. We recorded seeds of 27 taxa distributed in 12 families. Taxa richnessranged from 17 in LD to 25 in MC, and included seeds of terrestrial, palustrine and aquatic plants. River dischargedid not affect seed richness and density, which was probably associated with a homogenization process caused bythe flood. Seed buoyancy significantly differed between water movement treatments independently of the sourcecommunity, lasting longer in SW than in MW. Our results suggest that drifting macrophytes contribute to seeddispersal of several communities in the Middle Paraná River, and probably over long distances. Furthermore, seedbuoyancy might be more important for surficial dispersal in low-energy systems, where subaqueous dispersal maybe difficult due to the lack of current.