长江口滩涂种青效果影响因素分析

Analysis of factors affecting vegetation restoration on tidal flats in Yangtze River Estuary

在气候变化和人类活动的双重压迫下,长江口滩涂正面临动力侵蚀及生物入侵等威胁,为此上海市在淤涨滩涂进行了多次人工种青,以期恢复其湿地生境。其中,横沙和南汇东滩促淤区的种青成效显著,但南汇嘴和杭州湾南竹港出海闸外侧区域滩涂种青却效果不佳。总结了影响长江口种青植被——芦苇和海三棱藨草存活和扩散的主要因素,包括滩涂高程、水体盐度等关键阈值,并对种青的成功和失败案例进行了分析。研究表明:人工种青应选择在高程和盐度合适的淤涨光滩上开展,同时还需考虑水文动力条件和滩涂底质的影响。近年来实施的人工种青基本实现了湿地营造的预期目标。

Tidal wetlands are important environmental resources and land reserves,providing ecosystem functions including disaster prevention and mitigation,water purification,carbon storage and beach sequestration.Stressed by climatic and human activity disturbances,the tidal flats in the Yangtze River Estuary are threatened by coastal erosion and biological invasions.To this end,multiple artificial vegetation restorations have been carried out on the tidal flats within the Yangtze River Estuary.Hengsha and Nanhui east tidal flat have achieved remarkable effectiveness,while the restoration did not succeed on the tidal flat outside Nanhuizui and Nanzhugang of Hangzhou Bay.This study summarizes the main factors affecting the survival and dispersal of the restored vegetations,reeds and Scirpus mariqueter,including the key thresholds of bed elevation and salinity,and analyzes the cases of vegetation restoration.The results show that it is better to carry out the artificial vegetation restorations on silting mudflat and take hydrodynamic conditions and bottom sediment of the tidal flat into account.Following this guiding,we have succeeded in vegetation restoration on tidal flats in recent years.