黄河三角洲潮间带及近岸浅海大型底栖动物物种组成及长周期变化

黄河三角洲湿地是渤海重要的生态功能区, 在生物多样性保护与生态功能恢复方面发挥着重要作用。为系统研究该区域内大型底栖动物群落物种组成及时空分布, 作者在该区域典型潮间带和近岸浅海(5 m以浅水域)布设11个断面, 分别于2016年8月和11月, 2017年5月、8月和11月进行3个季节取样。结果显示: 黄河三角洲潮间带和邻近海域共发现大型底栖动物187种。其中, 潮间带分布119种, 近岸浅海分布99种。黄河三角洲潮间带和近海大型底栖动物物种组成均具有明显的时空差异。与历史资料相比, 黄河三角洲潮间带和近岸浅海大型底栖动物物种组成发生了明显变化, 动物个体呈小型化趋势。总体表现为自20世纪90年代末至今, 个体大的甲壳动物和软体动物经济类群逐渐被个体小且经济价值较低的多毛类、双壳类和甲壳动物取代。引起上述变化的原因复杂, 主要驱动力包括黄河来水量与输沙量的减少、人类活动(过度捕捞、开发力度加大)和互花米草(Spartina alterniflora)入侵。

Species composition and long-term variation of macrobenthos in intertidal zone and offshore areas of the Yellow River Delta

The Yellow River Delta wetlands play a major role in protecting the biodiversity and ecological function of the Bohai Sea. To understand the species diversity and spatial-temporal dynamics of macrobenthic community in this region, five surveys were carried out in intertidal zone and offshore areas in August and November 2016, May, August and November 2017, respectively. Results showed that 187 macrobenthic species were identified in surveyed areas, of which, 119 species were found in the intertidal zone and 99 in offshore areas. Obvious variation was found in the spatio-temporal distribution pattern of species composition. Compared to historical records, individuals of certain species presented a miniaturization trend in body size. The dominant species composition also has undergone an obvious change from large-sized crustacean and mollusc species toward small-sized polychaete, bivalve and crustacean species. Possible factors responsible for these changes are complex, including a decrease of water inflow and sediment transport by the Yellow River combined with human activities (overfishing and increasing exploitation) and other factors, e.g., salinity decrease and the invasion of Spartina alterniflora happened in the Yellow River Delta.