基于Ecopath模型的大亚湾海域生态系统结构与功能初步分析

大亚湾是位于广东省东部的重要经济活动区域,渔业资源捕捞和航道运输等行为改变了其生态系统结构和功能,因此,评估和可持续利用渔业资源需要计算该生态系统各功能组之间的相互作用。该研究通过Ecopath with Ecosim(EwE 6.4)软件,利用2012年大亚湾海域渔业资源调查数据将大亚湾生态系统划分为18个功能组和1个碎屑组,整体了解该生态系统能量流动、总体特征和各食物网结构。研究结果表明:大亚湾生态系统各营养级呈现金字塔结构,营养级范围在1~3.29级之间。食物链通道主要有2条,一条为牧食食物链,另一条为碎屑食物链。大亚湾生态系统营养级转换效率较低,生态系统总转换效率仅为8%。大亚湾生态系统总流量为6 249.573 t·(km~2·年)~(-1),系统总生产量为2 827.584 t·(km~2·年)~(-1),总净初级生产量为2 468.36 t·(km~2·年)~(-1),总初级生产量/总呼吸量(TPP/TR)为2.185,Finn循环指数(FCI)和平均能流路径(MPL)分别为4.8%和3.53,联结指数(CI)和系统杂食性指数(SOI)分别为0.324和0.174。综上,大亚湾生态系统食物网简单,稳定性较差,系统处于幼期阶段,亟须加强捕捞限制和资源环境保护。

Preliminary analysis of structure and function of Daya Bay ecosystem based on Ecopath model

Daya Bay,located in the eastern Guangdong Province,is an important economic region. Human activities such as fishing and waterway transportation have changed its ecological structure and function. Thus,assessment and sustainable utilization of fishery resources require study on the interaction among functional groups in the ecosystem. In the present study,Ecopath with Ecosim (EwE 6.4) software was applied to study the energy flow,general characteristics and food web structure in the whole ecosystem. Daya Bay has two main channels of food chain (grazing food chain and detritus food chain). The conversion efficiency among trophic levels in Daya Bay ecosystem was relatively low,the total energy transfer efficiency being just 8%. The total system throughput of the ecosystem was 6 249.573 t·(km2·year)-1. The total production was 2 827.584 t·(km2·year)-1. The total net primary production was 2 468.36 t·(km2·year)-1. The ratio of total primary productivity to total respiration (TPP/TR) was 2.185. Finn′s cycling index and the mean path length of the energy flow were 4.8% and 3.53,respectively. Connectance index and system omnivory index were 0.324 and 0.174,respectively. To sum up,the Daya Bay ecosystem is at an immature stage which has a simple food web,low maturity and poor stability. It is needed to enhance fishing restriction and improve environmental protection.