基于Ecopath模型的七连屿礁栖性生物的生态承载力分析

生态承载力评估是开展生物资源增殖放流, 维持珊瑚礁生态系统健康的基础和前提。本文基于2019年渔业资源和生态环境的综合调查数据, 构建了七连屿珊瑚礁海域生态系统的生态通道(Ecopath)模型, 分析和探讨了相关功能组增殖放流的生态承载力。结果显示, 七连屿珊瑚礁海域生态系统各功能群营养级范围为1.00~3.81; 生态系统的总能量转化效率为13.45%; 生态系统以牧食食物链占据主导地位, 直接来源于初级生产者的能流占比为57%。系统总初级生产量/总呼吸量为2.54; 总初级生产量/总生物量为19.07; 系统连接指数和系统杂食性指数分别为0.36和0.22, 表明当前七连屿珊瑚礁海域生态系统的成熟度和稳定性偏低, 系统对于外界的干扰抵抗能力较弱。在未改变七连屿珊瑚礁生态系统结构和功能的前提下, 各功能组中珊瑚、双壳类和植食性鱼类的生态承载力分别为25.09~53.77t•km^-2、2.55~39.95t•km^-2和4.89~17.94t•km^-2, 因此仍具有较大的增殖空间。珊瑚礁鱼类群落的最大生态承载力同珊瑚礁无脊椎动物群落的增殖密切相关, 在未来的珊瑚礁渔业管理中应从生态系统整体结构的角度综合考虑增殖放流的方法设计。

Analysis of ecological carrying capacity of reef organisms in Qilianyu Islands based on Ecopath model

Ecological carrying capacity assessment is the basis and premise for reef organisms of maintaining the health of coral reef ecosystem. Based on the survey data of the fishery resources and ecological environment in 2019, we developed an Ecopath model of the Qilianyu Islands coral reef ecosystem in the South China Sea. The ecological carrying capacities of some functional groups were analyzed by using the Ecopath model. The results show that the coral reef ecosystem was dominated by the grazing pathway, and the proportion of total energy flow originating from primary producers was 57%. Overall, the ratio of total primary productivity to total respiration was 2.54, and the ratio of total primary productivity to total biomass was 19.07. The connectance index and system omnivory index were 0.35 and 0.18, respectively. Outputs of the Ecopath model show that the maturity and stability of the coral reef ecosystem of the Qilianyu Islands were relatively low, and the ecosystem had weak resistance to external disturbances. Under the condition of stable ecosystem construction and sustaining the ecosystem, the ecological carrying capacities of functional groups of coral, bivalve and phytophagous fish were 25.09~53.77 t•km^-2, 2.55~39.95 t•km^-2 and 4.89~17.94 t•km^-2, respectively; their biomass still has a large growth space. The maximum ecological carrying capacity of coral reef fish communities was closely related to the multiplication of coral reef invertebrate communities. In the future of coral reef fishery management, the system design of stock enhancement should be considered from the perspective of the overall structure of the ecosystem.