State Key Laboratory of Estuarine and Coastal Research, Institute of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, 200241, Shanghai, China.
State Key Laboratory of Estuarine and Coastal Research, Institute of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, 200241, Shanghai, China; Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station (Ministry of Education & Shanghai Science and Technology Committee), 202162, Shanghai, China.
J Environ Manage. 2020 Jul 15;266:110631. doi: 10.1016/j.jenvman.2020.110631. Epub 2020 Apr 24.
The invasive plant Spartina alterniflora presents a serious threat to the saltmarsh ecosystems in the Yangtze Estuary. Various measures have been implemented to control S. alterniflora and restore the natural saltmarshes in this area. However, many saltmarsh restoration activities often fail partly because of recursions of this invasive plant. In this study, we investigated the re-invasion of S. alterniflora in a restored saltmarsh in the Chongming Dongtan National Nature Reserve by analysing the aspects of seed arrival, retention, germination, and establishment, to better understand the potential factors that may influence the re-invasion of restored saltmarshes. The results showed that 1) tidal currents dispersed the seeds from the possible source area to the restored saltmarsh and adjacent mudflat. The spatio-temporal dynamics of arrived seeds were shown to vary greatly depending on the intertidal geomorphology, vegetation, and hydrodynamic processes. 2) Seed retention in the re-invaded area was shown to be greatly influenced by burial depth, and moderate sedimentation rates provided safe sites for the retention of arrived seeds. 3) Only when both the burial depth and inundation duration below certain thresholds, the retained seeds could germinate and establish in the recipient habitats successfully. The results from this study highlight that control efforts and the management of S. alterniflora should not only focus on the re-invaded areas of restored saltmarshes, but also on the possible source areas of re-invasive species.
互花米草是一种入侵植物，对长江口盐沼生态系统构成严重威胁。为了控制互花米草并恢复该地区的自然盐沼，已经采取了各种措施。然而，许多盐沼恢复活动往往会失败，部分原因是这种入侵植物的再次入侵。在这项研究中，我们通过分析种子到达、保留、萌发和建立的各个方面，研究了崇明东滩国家级自然保护区恢复盐沼中互花米草的再次入侵情况，以更好地了解可能影响恢复盐沼再次入侵的潜在因素。结果表明：1）潮流将种子从可能的源区扩散到恢复的盐沼和相邻的泥滩。到达种子的时空动态变化很大，取决于潮间带地貌、植被和水动力过程。2）再入侵区域的种子保留受埋藏深度的影响很大，适度的沉积速率为到达种子的保留提供了安全场所。3）只有当埋藏深度和淹没持续时间低于一定阈值时，保留的种子才能在受纳生境中成功萌发和建立。本研究结果表明，控制工作和互花米草的管理不仅应集中在恢复盐沼的再入侵区域，还应集中在可能的再入侵物种源区。
