hydrochory

Hydrochory is a mode of seed and propagule dispersal in which water currents transport buoyant seeds, fruits, or other plant propagules away from the parent plant. It operates in both freshwater and marine systems, including rivers, lakes, wetlands, coastal shores, and islands. The dispersal unit is typically adapted to float, sometimes for long periods, and to remain viable after exposure to saltwater, desiccation, or immersion.

Mechanisms and adaptations vary. Buoyancy is often achieved by air-filled chambers, spongy tissues, thick seed coats, or specialized propagules that resist sinking. Some seeds or fruits detach and form rafts or fragments that drift with currents or tides. Dispersal can occur over short distances along streams or over long distances across oceans, depending on water movement and propagule durability. Hydrochory is influenced by hydrological regimes such as floods, currents, and tides, which determine the direction and extent of dispersal.

Ecological significance and examples. Hydrochorous dispersal enables colonization of new habitats along rivers and coastlines, contributes to genetic connectivity between populations, and can drive rapid range shifts in response to changing water regimes. Iconic examples include buoyant propagules of coastal and mangrove species that can float across open water, as well as aquatic macrophytes whose seeds or fragments float to establish in new wetlands. Invasive species can also spread via hydrochory, underscoring its role in ecosystem dynamics and management.

Research and applications. Studying hydrochory involves buoyancy experiments, seed viability testing after immersion, and hydrological modeling to predict dispersal pathways. Understanding hydrochorous dispersal informs wetland restoration, island biogeography, and the control of aquatic invasive species.