长江口及邻近水域的生物多样性变化趋势分析

Tendency of the Biodiversity Variation Nearby Changjiang Estuary

从长江口及邻近水域的生物多样性变化及导致生物多样性变化的相关环境因子来剖析长江口及邻近水域的生态环境变化趋势。长江口及邻近水域的生物多样性比较丰富，近 20 a 来在人类活动影响下，长江河口区和冲淡水区浮游生物和底栖生物的物种大幅减少；优势浮游生物的生物量增加，部分种类异常增殖发生赤潮，底栖生物生物量明显减少；群落结构趋向简单，表现为单种优势，生物多样性下降。影响长江口及邻近水域生物多样性的原因包括自然因素和人为因素，近 20 a 来生物多样性的降低主要归咎于人类的开发活动，不合理排污导致的富营养化对浮游生物的多样性丧失起重要作用，水利工程建设及滩涂围垦使海洋生物栖息地片段化，单调化，加速了生物多样性的降低。

Based on the biodiversity and related environmental factors, the tendency of ecology and environment nearby Changjiang estuary is analyzed. The biodiversity of plankton and benthos nearby Changjiang estuary is abundant at present, but the species number of plankton and benthos has decreased dramatically as compared with 20 years ago, the biomass of dominant plankton has increase and some species tend to form a bloom. The biomass of benthos decreases visibly, the community structure of plankton and benthos becomes symplified and the biodiversity lower. The natural factors and human activities both influence the biodiversity of the Changjiang estuary, and the fall of biodiversity for the past decades is mainly due to the latter. The eutrophication induced by unreasonable wastewater discharging plays on important role in the decrease of biodiversity, the engineering works along Changjiang river and around Changjiang estuary and beach land inning simplify and damage the habitat of benthos, thus accelerating the decrease of biodiversity.