基于Ecopath模型的长江口生态系统结构与功能分析

A preliminary analysis of the ecosystem structure and function of the Yangtze Estuary based on Ecopath model

依据2020年春季(5月)和秋季(11月)2次长江口渔业资源和生态环境调查数据,构建长江口生态系统Ecopath模型,分析了长江全面禁渔前夕,长江口水域生态系统的结构和能量流动特征。模型共包括龙头鱼、凤鲚、刀鲚、舌鳎、浮游动物食性鱼类、底栖生物食性鱼类、游泳生物食性鱼类、杂食性鱼类等17个功能组,基本覆盖了长江口生态系统能量流动过程。结果表明,长江口生态系统营养级集中在1.000~4.438,龙头鱼营养级最高,其他鱼类营养级集中在2.907~3.768,分布较广;底栖生物、软体动物和虾蟹类的营养级集中在2.365~2.826。长江口生态系统各营养级的能量流动分布主要集中在营养级Ⅰ~Ⅱ中,来自营养级Ⅰ的能量流动在系统总能量流动中占比最高。长江口生态系统的能量流动以牧食食物链传递为主。与过去相比,2020年长江口生态系统总初级生产量/总呼吸量(TPP/TR)较高,连接指数(CI)与系统杂食指数(SOI)有所上升,但仍小于1,表明长江口生态系统仍不成熟,总体处于发育阶段。

Based on the survey data of the Yangtze Estuary fishery resources and ecological environment survey in spring(May)and autumn(November)in 2020,the Ecopath model of the Yangtze Estuary ecosystem was established to analyze the ecosystem structure and energy flow characteristics of the Yangtze Estuary before the total fishing ban of the Yangtze River.The model consisted of 17 functional groups,including Harpadon nehereus,Coilia mystus,Coilia nasus,tongue sole,zooplankton feeding fish,benthic feeding fish,swimming feeding fish and omnivorous fish,which basically covered the energy flow process of the Yangtze Estuary ecosystem.The results showed that the trophic level of the Yangtze Estuary ecosystem ranged from 1.000 to 4.438,with the highest trophic level of Harpadon nehereus and the trophic level of other fish ranging from 2.907 to 3.768,which was widely distributed.The trophic levels of benthos,molluscs,shrimp and crabs were concentrated from 2.365 to 2.826.The energy flow distribution of each trophic level in the Yangtze Estuary ecosystem mainly concentrated in trophic levelⅠtoⅡ,and the energy flow from trophic level I accounted for the highest proportion of the total energy flow in the system.The energy flow of the Yangtze Estuary ecosystem was mainly transferred by the grazing food chain.Compared with the past,TPP/TR value of the Yangtze Estuary ecosystem in 2020 was higher,while CI value and SOI value increased,but were still less than 1,indicating that the Yangtze Estuary ecosystem was still immature and in the development stage.