Long‐term Spartina alterniflora invasion simplified soil seed bank and regenerated community in a coastal marsh wetland

Abstract

The coastal wetland is easily invaded by alien species due to locating in the land and sea transitional area. As a potential driving regeneration force, the soil seed bank is vital to the community restoration and species diversity protection. To reveal the long‐term Spartina alterniflora invasion impact on the soil seed banks and regenerated communities, we investigated the seed banks under the different vegetation types (S. alterniflora, Phragmites australis, Scirpus mariqueter, ruderal and unvegetated site) and soil depths (0–5 and 5–10 cm) in the coastal salt marsh wetland, Chongming island, eastern China. The results showed that the soil seed bank richness and species density under different vegetation types were higher than the aboveground vegetation, and those of 0–5 cm seed banks were higher than 5–10 cm, except for the unvegetated site. The species richness and S. alterniflora seed proportion in the seed banks under S. alterniflora communities (S.AS) were lower and larger respectively than those of other sites. The species composition between S.AS and the aboveground communities showed high similarity with aggregation phylogenetic structures in two soil depths. The seed bank variations at 0–5 and 5–10 cm depths were interpreted 3.03% and 2.25% by the aboveground communities, while 4.92% and 5.55% were interpreted by the soil microbial biomass. The SEM model explained 98.1% and 91.8% of the seed banks richness at the 0–5 cm depth and 5–10 cm depth, respectively, and explained 98.8% and 46.1% of the seed banks species density at the 0–5 cm depth and 5–10 cm depth, respectively. The aboveground vegetation biomass and abundance directly affected the 0–5 cm seed banks richness and species density, while its height and biomass only affected the 5–10 cm seed banks species density. The 0–10 cm soil depth microbial biomass indirectly affected the 0–5 cm seed banks richness and species density, while affected the 5–10 cm seed banks richness. Soil physical and chemical properties only indirectly affected the 0–5 cm seed banks species density. The results provided a reference for the ecological evaluation of the impacts of S. alterniflora invasion into the coastal salt marsh wetland of eastern China, and guidance for the protection and restoration of the native plant communities.

The spatial overlapping regulated by nitrogen promotes the Spartina alterniflora potential regenerated invasion in coastal wetlands

“…The transformation of environmental conditions by S. alterniflora and symbiotic species is a key step to consolidate the results of invasion (Ning et al 2019;Shang et al 2015). The soil seed bank structure under S. alterniflora community in Dongtan wetland was highly similar to that of aboveground community, indicating that the soil seed bank had similar environmental requirements with aboveground vegetation, which ensured the potential dominant status of S. alterniflora in the community formed by soil seed bank (Jia, et al 2022).…”

“…The special environment of Dongtan coastal wetland be beneficial to the survival and maintenance of native species (P. australis, Scirpus mariqueter and Scirpus triqueter, etc.) community, and the soil seed bank has made great contributions to community stabilization (Jia et al 2022). Although the invasion of alien species has been widely studied (Nie et al 2023), the exact way of seed dispersal and its related effects are still unclear.…”

Perspectives of invasive alien species management in China

“…The soil seed bank plays a vital role in community restoration and species diversity protection. Jia et al (2023) discovered that soil seed banks potentially played important roles in the restoration of depredated coastal salt marsh wetlands. These results provide valuable insights for evaluating the ecological impacts of S. alterniflora invasions in eastern China's coastal salt marsh wetlands and offer guidance for the protection and restoration of native plant communities.…”