Tides as a key factor driving effective seed dispersal in coastal wetlands

Seed dispersal is a key process in the conservation of coastal wetland vegetation. In this study, we selected a typical plant of the Yellow River Delta, namely, Suaeda salsa, to explore its dispersal process and environmental impact factors. The seed flow of S. salsa gradually increased along the direction from the sea to the inland, and the seed flow in the supratidal zone was significantly greater than that in the intertidal and subtidal zones. Seed germination in the subtidal zone was the smallest, whereas the intertidal zone was the largest. Different tidal zones also had significant effects on seed germination. In addition, by analyzing the relationship among tidal inundation frequency, inundation depth, distance from the tidal channel, elevation, soil water and salinity, and seed flow and germination, the influence of tides was more significant than microtopography as well as soil water and salinity. In coastal wetlands, tides were the key factor affecting seed dispersal. In particular, seed flow and germination decreased with the increase of tidal inundation frequency and depth, but they were inhibited by the strengthening of tides within a certain range. Overall, different tidal zones should be selected for the recovery of different stages of seed dispersal and germination, while also taking tidal characteristics into account.