J* E* C* N* U* N* S* ›› 2026, Vol. 2026 ›› Issue (3): 134-147.doi: 10.3969/j.issn.1000-5641.2026.03.011

• Biodiversity and Ecological Responses • Previous Articles     Next Articles

Evolution of biodiversity in the Doulonggang estuary coastal wetland, Yancheng, China

Haixia WEN1,2, Qing HU3, Zhanghua WANG1,2, Xiaolin MA1,2,*()   

  1. 1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
    2. Zhejiang Zhoushan Island Ecosystem Field Scientific Observation and Research Station, East China Normal University, Shanghai 200241, China
    3. Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
  • Received:2025-03-19 Accepted:2026-03-02 Online:2026-05-25 Published:2026-05-27
  • Contact: Xiaolin MA E-mail:xlma@sklec.ecnu.edu.cn

Abstract:

Coastal wetlands play an important role in the ecosystem. However, human activities such as pond aquaculture can alter their landscape patterns and biodiversity in the ecosystems. Environmental DNA (eDNA) technology can effectively reconstruct past biological communities and evaluate changes in biodiversity. In the present study, a sediment core was obtained from a wetland at the Doulonggang estuary in Yancheng, Jiangsu Province. By analyzing eDNA in the sediments and historical remote sensing images, in addition to performing 210Pb dating, the present study comprehensively explored how land use change affected biodiversity in the 2008–2023 period. 210Pb dating and historical remote sensing data showed that the sedimentary records included three phases of land use, including natural wetland (2008–2015), aquaculture ponds (2015–2019), and wetland restoration (2019–2023). eDNA in the sediments indicated that in the natural wetland phase, terrestrial herbaceous plants (26.69%~37.90%) and a brackish water community prevailed. In the aquaculture pond phase, the proportions of aquatic arthropods (such as Calanoida) and algae surged sharply, reflecting the ecological simplification caused by the artificial aquaculture system. In the wetland restoration phase, the proportion of diatoms (Bacillariophyta) increased to 89.04%, and the terrestrial herbs recovered gradually, indicating ecosystem restoration. The α-diversity index further confirmed that species diversity and evenness were the lowest when the area became an aquaculture pond in 2015 and then recovered gradually. The Bray-Curtis similarity index showed that there were significant differences in the biological composition among the three phases, with the main difference attributed to the proportion of diatoms. Therefore, this study shows that the ecological restoration project has enabled the wetland biological composition at the Doulonggang estuary to recover toward a natural wetland state. However, restoration of the ecosystem lags behind the landscape change, and long-term monitoring is necessary to promote the complete ecological restoration of the wetland. This study contributes to a deeper understanding of the dynamic change process of coastal wetland ecosystems under the interference of human activities and provides a scientific basis for ecological restoration and management of tidal flat wetlands.

Key words: coastal wetland, environmental DNA, land use, biodiversity, reclamation, ecological restoration

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