北部湾北部生态系统结构与功能研究Ⅶ:基于Ecopath模型的营养结构构建和关键种筛选

Analysis of ecosystem structure and function in the northern Beibu Gulf Ⅶ: Nutrition structure and keystone species selection based on Ecopath with Ecosim

本研究根据2006—2007 年在北部湾北部(107?51′04″~109o56′07″E; 19?44′12″~21?27′46″N)我国领海一侧海域进行的4 个季度的生物调查数据, 运用Ecopath with Ecosim模型构建起北部湾北部生态系统食物网结构, 并对该海域生态系统中的关键种进行了探索性筛选。研究结果表明北部湾北部生态系统的有效营养级范围在1.00~4.03 之间, 其中营养级最高的是软骨鱼类。以碎屑、浮游植物及细菌为起点, 整个生态系统包括三条食物链。各功能组之间的混合营养效应值范围在–1.09 到0.54 之间, 其中61.60%的功能组彼此间存在竞争关系, 反映出北部湾北部生态系统中生物类群间存在较为复杂的竞争关系, 除碎屑外各功能组自身内部存在捕食和生存空间的竞争压力。北部湾北部浮游动物中的关键物种是肥胖软箭虫(Flaccisagitta enflata), 并且其也为整个生态系统中的关键种; 鱼类中的关键种为二长棘鲷(Paerargyrops edita),其关键度指数排在整个生态系统的第4 位; 另外浮游植物在整个生态系统中也具有很高的关键度, 其关键度排在整个生态系统中的第三位。本研究对该海域关键种的筛选对北部湾北部海域的营养动力学研究和渔业生产活动具有一定的理论研究和实践意义。

This study was based on the data of four surveys in the northern Beibu Gulf (107?51′04?~109?56′07?E; 19?44′12?~21?27′46?N) in 2006 and 2007, using Ecopath with Ecosim model to study the biological community structure and select thekeystone species in the northern Beibu Gulf. The results showed that the ecosystem trophic levels ranged from 1.00 to 4.03,and the highest trophic level was Elasmobranchs. There were three food chains with the origin of detritus, phytoplankton andbacteria. The mixed trophic impacts among the functional groups ranged from –1.09 to 0.54, and 61.60% species hadcompetitive relationship to each other. This result showed that there were complex competitions among the functional groups in the northern Beibu Gulf. In the end, with the keystone index of the Ecopath model, Flaccisagitta enflata was not only thekeystone specie of zooplankton but also the keystone specie among all the functional groups; Parargyrops edita had thehighest keystone index among fish functional groups, and the fourth highest keystone index among all the functional groups;phytoplankton had the third highest keystone index in the ecosystem. This research may provide certain reference for thetrophodynamics and fishery activities in the northern Beibu Gulf.