Evaluation of the Control Effect of Spartina alterniflora Based on eDNA: Biodiversity Responses to Plowing, Flooding and Mowing

The Yancheng National Nature Reserve for Rare Birds in Jiangsu Province is a vital coastal tidal wetland reserve. However, the invasive species Spartina alterniflora has caused significant ecological damage to its ecosystem. Therefore, controlling S. alterniflora and evaluating biodiversity restoration are of critical ecological importance. In this study, we implemented a combination of cutting, flooding, and plowing to suppress S. alterniflora in the reserve. Subsequently, eDNA technology was employed to sample and analyze fish and zooplankton communities. Community structure recovery was quantified using Shannon, Simpson, and Pielou indices. Biodiversity indices revealed distinct restoration patterns: plowed sites showed the poorest recovery of zooplankton and fish communities, while cut sites demonstrated optimal biodiversity restoration. Flooded sites exhibited intermediate but still significant recovery. The successful application of eDNA metabarcoding in this study underscores its value as a robust tool for assessing aquatic biodiversity restoration. While our results reveal treatment-specific recovery patterns, they also emphasize two critical research directions: first, the necessity for long-term monitoring of S. alterniflora management outcomes, and second, the importance of expanding taxonomic coverage to fully evaluate ecosystem recovery.