海州湾鱼类β多样性变化

Variation in the β diversity of fish species in Haizhou Bay

海州湾海域渔业资源丰富,但近年来由于过度捕捞、环境污染的影响,渔业资源严重衰退。为了解海州湾鱼类β多样性的时空变化规律,本研究根据2011年、2013—2019年在海州湾海域进行的8个航次秋季渔业资源底拖网调查数据,采用Chao和自助法两种非参数统计方法,估算调查海域的鱼类物种丰富度,并采用Sorenson和Cody指数等多种β多样性的度量方法,计算了鱼类物种β多样性。海州湾海域调查共捕获鱼类94种,鱼类物种数和β多样性均在近年间呈现波动下降趋势。利用K均值聚类将调查站位按20 m等深线划分为组Ⅰ (<20 m)和组Ⅱ (>20 m),进一步的β多样性空间差异分析表明,组Ⅱ的β多样性呈现相对明显的下降趋势,而组Ⅰ无明显变化;两组间Cody替代性指数随时间降低,而Sorenson相似性指数略有升高,表征了深水区与浅水区β多样性的变化趋势有着显著差别。研究结果表明海州湾海域的鱼类群落呈现生物同质化趋势,该趋势的出现可能与过度捕捞、环境变化等原因有关。本研究旨在为渔业资源的养护、海洋保护区的建设提供科学依据。

Species diversity is one of the most important characteristics of biological communities and an important factor affecting the function and stability of ecosystems.The variation in diversity has been a topic of great interest in ecological research for many years,whereasβdiversity,an important aspect of species diversity,has been studied in terrestrial ecosystems and freshwater ecosystems more than in marine ecosystems.Haizhou Bay is a traditional fishing ground in the Yellow Sea and historically has had rich fishery resources.However,the fishery resources in Haizhou Bay have seriously declined in recent years due to overfishing,environmental pollution,and human activities.The purpose of this study was to understand the temporal and spatial variation inβdiversity of the fish species in Haizhou Bay to provide a scientific basis for the conservation of fishery resources and the construction of protected marine areas.The data in this study were collected from fishery resource surveys conducted in Haizhou Bay in the autumn of 2011 and 2013–2019 using bottom trawl.Non-parametric methods,including the Chao’s and Bootstrap approaches,were used to estimate the number of fish species,namely species richness,in the entire area of Haizhou Bay and in each sampling station.On this basis,βdiversity was calculated according to the additive principle with a variety of measurement methods,including Sorenson’s index and Cody’s index,which reflects the similarity of species composition between the two groups and the substitutability between groups,respectively.To evaluate the spatial variation inβdiversity,survey stations were divided into two groups along the 20 m isobath roughly by K-Means Cluster.The results of this study showed that the richness andβdiversity of the fish species in Haizhou Bay decreased significantly in recent years,the Cody’s index decreased,and the Sorenson’s index increased slightly.The result reflected biotic homogenization in the marine ecosystem and it also indicated a remarkable difference in the trend ofβdiversity between deep water and shallow water.The decline in biodiversity has become a common phenomenon,which is closely related to human activities,especially long-term overfishing.In addition,environmental factors,especially the rise of sea water temperature,also contribute significantly to biotic homogenization.In summary,our research indicated that the abundance andβdiversity of the fish species in Haizhou Bay decreased substantially from 2011 to 2019,and these changes were associated with the life history of fish species and their adaptability to the environment.These changes were also closely related to human activities,such as overfishing,environmental pollution,habitat destruction,and the water temperature increase caused by climate change.The driving mechanism remains to be further explored.In-depth studies onβdiversity are helpful for understanding the fluctuation of marine fish communities,managing and protecting fishery resources,and providing a reference for constructing marine protected areas,which have great significance to the sustainable use of fishery resources and the protection of biodiversity.