Abstract:
Soil seed bank is an important component of biodiversity and plays an important role in restoration and reconstruction of wetlands and the succession and renewal of vegetation. To reveal the characteristics of soil seed bank and its influencing factors of the newly formed intertidal wetland, we selected the intertidal wetland of the Yellow River Delta formed from 1996 as the study area and used the method of combining field sampling and indoor culture in March 2023. The results showed that the species composition of the soil seed bank in the study area was relatively simple, only 4 species were found, which belong to 3 families and 4 genera, all of which were herbaceous plants.
Suaeda salsa was the dominant species, and there were more species in the shoreline of the tidal creek and the sea side sampling transect. The average density of the seed bank in the study area was (572.22±468.22) p/m
2, with higher densities appeared in both sides of the tidal flats and sea side, land side sampling transects, and the seed bank density near the shore of tidal creek and the intermediate sampling transect was lower, whose horizontal distribution was similar to the “V” shape. In the vertical direction, the seed bank density was higher at the depths of 5-10 cm and 10-15 cm. The diversity of seed bank was relatively low, and the similarity with the surface vegetation was not high. The Patrick indices, Shannon-Wiener indices, Simpson indices and Pielou indices of the seed bank were higher along the shoreline of the tidal creek, the sea side sampling transect and the surface layer of the soil (0-5 cm), which showed a richer species composition and diversity, and a more uniform distribution compared with other sampling points. However, the Jaccard indices in most sampling points were lower than 0.50, which showed a low degree of similarity with the surface vegetation. Environmental factors affected the species composition, density and diversity characteristics of the soil seed bank. Soil pH and electrical conductivity showed a direct effect on the characteristics of the seed bank, while water fluctuation affected the seed bank indirectly by changing the soil burial depth of the seed bank, soil pH, electrical conductivity, nutrient content, and so on.