Effects of salinity and waterlogging frequency on the dynamics of soil seed bank in the coastal area of chongming dongtan salt marsh wetland in Shanghai

Taking the soil seed banks of different communities (habitats) in the coastal area of Chongming Dongtan salt marsh wetland in Shanghai as research objects, tidal action was simulated in a greenhouse to explore the effects of soil salinity, waterlogging frequency, and their interactions on the germination dynamics of soil seed banks. The results show that a total of 13 plant species belonging to 12 genera of 7 families germinate from the soil seed banks of × Bolboschoenoplectus mariqueter (Tang et F. T. Wang) Tatanov community, Spartina alterniflora Loisel. community, Phragmites australis (Cav.) Trin. ex Steud. community, and the unvegetated habitat in the coastal area of Chongming Dongtan salt marsh wetland, among which the total frequencies of × B. mariqueter, Digitaria sanguinalis (Linn.) Scop., and Digitaria ciliaris (Retz.) Koeler are relatively high, which are 0.108, 0.064, and 0.059, respectively. The Poaceae and Cyperaceae are typical families of germinated plant communities in the soil seed banks of the coastal area of Chongming Dongtan salt marsh wetland. The soil seed banks of native plant (× B. mariqueter and P. australis) communities mainly germinate X B. mariqueter, D. sanguinalis, and D. ciliaris ; while the soil seed bank of invasive plant (S. alterniflora) community mainly germinates D. sanguinalis, D. ciliaris, and Tripolium pannonicum (Jacquin) Dobroczajeva, among which T. pannonicum only germinates in the soil seed bank of S. alterniflora community. The soil seed bank of × B. mariqueter community exhibits relatively strong tolerance to different salinities and waterlogging frequencies. Except for the unvegetated habitat, the soil seed banks of the other three communities all have germination of × B. mariqueter under the treatment conditions of salinities of 0.0%, 0.5%, 1.0%, and 1.5% and waterlogging frequencies of 1, 3, 7, and 10 d. Compared with the control (freshwater wetting) treatment condition, different salinity and waterlogging frequency treatments significantly (P < 0.05) reduce the plant density and species diversity of the germinated plant communities in the soil seed banks of this area. In conclusion, utilizing the soil seed bank is a feasible approach when restoring native plant communities in Chongming Dongtan salt marsh wetland, and the soil seed bank of × B. mariqueter community is particularly recommended.