海草床种子扩散过程及种子库形成机制研究进展

海草是唯一一类可以完全生活在海水中的高等被子植物，具有重要的生态服务功能和巨大的经济价值。但受气候变化和人类活动的双重影响，海草床退化趋势日益严峻。海草床生态系统受到外界胁迫后的稳定性和恢复能力很大程度上依赖于有性繁殖即种子繁殖，当胁迫造成海草死亡等不可逆转的伤害时，通过沉积物种子库能够进行种群维持和自我更新，因此研究海草种子扩散过程及种子库形成机制对海草生态系统稳定性的维持具有重要意义。综述了海草生活史类型、种子繁殖特征、种子扩散过程及影响因素、种子库形成机制等。在此基础上总结了目前研究存在的几方面不足和未来展望：1)不同环境胁迫条件对海草有性繁殖努力的影响研究；2)海草种子二次扩散的影响因素和扩散机制研究；3)沉积物沉降和再悬浮对种子扩散和截留的影响研究；4)环境因素变化下种子库的潜在分布和海草适宜生境预测与模拟。本研究以期为海草床生态系统的保护恢复研究提供理论参考。

A review on seed dispersal process and mechanism of seed bank formation of seagrass meadows

Seagrasses are the only higher angiosperms fully living in marine environments, which have important ecosystem service functions and enormous economic value. However, in recent years, the structure and function of seagrass ecosystems have been threatened by multiple global stressors caused by human activities and climate change, resulting in the continuous degradation of seagrasses. The stability and resilience of the seagrass ecosystem under external stress depend highly on its sexual reproduction, i.e., seed reproduction. When stressors cause irreversible damage to seagrasses, population maintenance and self-renewal could occur through sediment seed banks. Therefore, it is crucial to study the dispersal processes of seeds and the mechanism of seed bank formation, which play a key role in maintaining seagrass ecosystem stability. This paper reviews the life-history types, seed reproductive characteristics, seed dispersal processes and their influencing factors and seed bank formation of seagrass. On the basis of these understandings, we further proposed that future studies should focus on: 1) sexual reproductive efforts of seagrass under different environmental stress conditions; 2) the influencing factors and mechanism of secondary dispersal of seagrass seeds; 3) the influence of sediment deposition and resuspension on seed dispersal and retention processes; 4) prediction and simulation of the potential distribution of seagrasses and suitable habitat of seed bank under changing environments. This study is expected to provide theoretical references for the protection and restoration of seagrass meadow ecosystems.