Coastal vegetation both mitigates the damage inflicted by marine disasters on coastal areas and plays an important role in the global carbon cycle (i.e., blue carbon). Nevertheless, detailed records of changes in coastal vegetation composition and diversity in the Holocene, coupled with climate change and river evolution, remain unclear. To explore vegetation dynamics and their influencing factors on the coastal area of the Bohai Sea (BS) during the Holocene, we present high-resolution pollen and sediment grain size data obtained from a sediment core of the BS. The results reveal that two rapid and abrupt changes in salt marsh vegetation are linked with the river system changes. Within each event, a recurring pattern – starting with a decline in Cyperaceae, followed by an increase in Artemisia and Chenopodiaceae – suggests a successional process that is determined by the close relationship between Yellow River (YR) channel shifts and the wetland community dynamics. The phreatophyte Cyperaceae at the base of each sequence indicate lower saline conditions. Unchannelized river flow characterized the onset of the YR channel shift, caused a huge river-derived sediment accumulation in the floodplain and destroyed the sedges in the coastal depression. Along with the formation of a new channel, lateral migration of the lower channel stopped, and a new intertidal mudflat was formed. Pioneer species (Chenopodiaceae, Artemisia) were the first to colonize the bare zones of the lower and middle marsh areas. In addition, the pollen results revealed that the vegetation of the BS land area was dominated by broadleaved forests during the Early Holocene (8500–6500 BP) and by conifer and broadleaved forests in the Middle Holocene (6500–3500 BP), which was followed by an expansion of broadleaved trees (after 3500 BP). The pollen record indicated that a warmer Early and Late Holocene and colder Middle Holocene were consistent with previously reported temperature records for East Asia. The main driving factors of temperature variation in this region are insolation, the El Niño–Southern Oscillation and greenhouse gases forcing.

中文翻译：

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渤海地区全新世植被动态对气候变化和水文过程的响应

沿海植被既减轻了海洋灾害对沿海地区造成的破坏，又在全球碳循环（即蓝碳）中发挥了重要作用。然而，尚不清楚全新世沿海植被组成和多样性的变化以及气候变化和河流演变的详细记录。为了探索全新世期间渤海沿海地区的植被动态及其影响因素，我们提供了从该地区沉积物核心获得的高分辨率花粉和沉积物粒度数据。结果表明，盐沼植被的两次快速和突变与河流系统的变化有关。在每个事件中，都有重复发生的模式-从莎草科的减少开始，然后是蒿的增加藜科和藜科–提出了一个演替过程，该过程由黄河（YR）河道转换与湿地群落动态之间的紧密关系决定。在每个序列的底部的莎草莎草科指示较低的盐条件。YR河道移动的开始是无渠道的河水流动，在洪泛区引起了巨大的河流沉积物堆积，破坏了沿海洼地的莎草。随着新河道的形成，下部河道的横向迁移停止了，并形成了新的潮间带滩涂。先锋物种（藜科，蒿）是第一个在低沼泽和中沼泽地区的裸露区域定居的人。此外，花粉结果表明，BS区域的植被主要由全新世早期（8500-6500 BP）的阔叶林和中全新世（6500-3500 BP）的针叶林和阔叶林控制。通过扩大阔叶树（3500 BP后）。花粉记录表明早新世和晚新世较温暖，中新世较冷与先前报道的东亚温度记录一致。该地区温度变化的主要驱动因素是日照，厄尔尼诺-南方涛动和温室气体强迫。