东海南部海区生态系统结构与功能的模型分析

Ecological modeling on structure and functioning of southern East China Sea ecosystem

关键词:  生态通道模型  东海南部海区  生态网络分析  生态系统成熟度

Key words:  Ecopath with Ecosim  Southern East China Sea  Network analysis  Ecosystem maturity

摘要:

根据1999~2002年间对东海南部海区的渔业资源和生态环境进行调查后所获得的数据和资料，应用Ecopath with Ecosim 5.1软件构建了该海区生态系统的生态通道模型，基于该模型对生态系统结构特征进行了量化分析。生态通道模型由20个功能组构成，基本覆盖了东海南部海区生态系统能量流动的主要过程。分析结果表明，东海南部海区生态系统各功能组的营养级为1.00~4.23，能量流动主要由6个整合营养级构成，营养级I的利用效率颇为低下，大量初级生产力未进入更高层次的营养流动，造成生态系统下层营养流动的“阻塞”。 鲹科鱼类、沙丁鱼、鳀科鱼类和其他小型鱼类的生产量较高，占鱼类总生产量的85.6%，而其他大中型肉食性鱼类的生产量都较低。混合营养分析表明，在能量从低级向高层次转化的食物网中，底层功能组起关键作用。反映系统成熟度的指标，包括较高的净初级生产力（NPP）和净初级生产力/呼吸（NPP/R），以及较低的连接指数（CI）、系统杂食指数（SOI）和Finn’s循环指数（FCI）等，均表明该海区处在一个“幼态化”的生态系统。

Abstract:

An exploited ecosystem of the southern East China Sea in 1999~2002 was described by means of an ecopath mass-balance model with the aim of characterizing its function and structure. This application included some complexities added to the general modeling methodology due to the high biodiversity of the East China Sea and the multispecies nature of the fishery, and the difficulties of working with fishing data which are usually irregularly or imprecisely collected. The model comprised 20 functional groups including primary producers, the main species of benthic, demersal and pelagic invertebrates, fishes and non-fish vertebrates and detritus. Results showed that the functional groups were organized into six trophic levels with the highest levels corresponding to the top predators, shark and rays. The system was dominated by the pelagic fraction, where sardines and anchovy prevailed in terms of fish production, biomass and catches. Detritus and detritivorous groups also played key roles in the ecosystem. Considering Odum's theory of ecosystem development, the ecosystem was placed on a low developmental stage with high net primary production (NPP), net primary production/total respiration (NPP/R) and lower connectance index (CI), system omnivory index (SOI) and finn's cycling index (FCI).