环境胁迫下的西沙珊瑚礁生态系统多情景模拟与动态仿真研究

Dynamic simulation study and multi-scenario simulation of coral reef ecosystem based on environmental stres

本文以西沙生态监控区为研究区域,综合考虑西沙珊瑚礁生态系统与环境变化的多重反馈关系,运用系统动力学方法构建了西沙珊瑚礁生态系统动力学模型,并选取长棘海星暴发、海水温度、海水pH和陆源沉积四种环境因子,设置基础模拟、单因子扰动、双因子扰动和多因子扰动四种典型干扰情景,分析西沙珊瑚礁生态系统的整体演化过程。结果表明:(1)系统动力学对西沙珊瑚礁生态系统反馈机制的模拟和诊断,为分析珊瑚礁生态系统整体演化过程提供了一种可行性的方法;(2)基础情景模拟表明在外界条件保持不变情况下,40年间珊瑚面积年均下降率为4.8%,珊瑚礁存在退化风险;(3)在叠加海水温度、海水pH和陆源沉积三类环境调控因子时,单一移除长棘海星对扭转西沙珊瑚礁生态系统退化趋势并不明显,应在移除长棘海星的基础上,综合考虑海水温度、海水pH和陆源沉积等胁迫因子,共同保护和修复西沙受损珊瑚礁;(4)多因子扰动下珊瑚礁生态系统退化的速度和规模远大于单因子扰动和双因子扰动,系统演化更加复杂。研究结果可为西沙珊瑚礁生态系统的动态演化提供借鉴,也为后续西沙珊瑚礁生态系统的诊断和修复奠定基础。

Taking Xisha ecological monitoring area as an example,the multiple feedback effects of coral reef ecosystem and environmental changes were analyzed.The system dynamics method was used to construct a dynamic model of the Xisha coral reef ecosystem.The four environmental factors were selected including the eruption of crown-of-thorns starfish,ocean temperature,ocean pH and terrestrial deposition.The basic simulation,single-factor disturbance,double-factor disturbance,and multi-factor disturbance were set up.The overall evolution process of Xisha coral reef ecosystem was investigated.The results showed that:(1)The system dynamics simulation and diagnosis of the feedback mechanism of the Xisha coral reef ecosystem provided a feasible method for analyzing the overall evolution process of the coral reef ecosystem;(2)The basic scenario simulation showed that the external conditions remained unchanged under the circumstances,and the average annual decline rate of coral area in the past 40 years was 4.8%,and the coral reefs were at a risk of degradation;(3)When the three environmental control factors of sea temperature,sea pH,and terrestrial sediment were superimposed,the single removal of crown-of-thorns starfish could reverse the Xisha coral reef.The ecosystem degradation trend was not obvious.On the basis of effective implementation of the removal of long thorn starfish,the three major environmental stress factors of sea temperature,sea pH and terrestrial sediment should be considered comprehensively to jointly protect and repair the damaged coral reefs of Xisha;(4)The degradation rate and scale of the coral reef ecosystem under multi-factor disturbance were far greater than the single with factor disturbance and two-factor disturbance,and the system evolution was more complicated.The research results provided a reference for the dynamic evolution of coral reef ecosystem and lay the foundation for subsequent diagnosis and restoration of coral reef ecosystem.