池塘养殖(青虾)生态系统服务价值的系统动力学模型

生态服务价值的评估在近10 a来受到广泛关注,但大多基于静态评估框架,缺少动态分析。研究运用系统动力学的原理和方法,分析了青虾池塘养殖生态系统服务价值评估系统的内部结构,描绘了因果关系图及流图,建立了相应的系统动力学模型,初步预测不同决策方案下食物供给、固碳、释放氧气价值和富营养化环境成本在30 a内的变化趋势,结果表明:①无论采取何种决策,若系统外部环境不变,生态系统净服务价值的供给趋于稳定;②在池塘养殖生态系统中,释放氧气和固定二氧化碳等非市场价值是生态系统服务价值重要稳定的来源;③青虾养殖中投资变动在短期内往往会造成水产品市场价值的大幅波动,长期里则因投入的增加而增加,但增加率逐渐减少,最终达到稳定值;④在当前条件假设和环境参数的约束下,模型模拟结果与实测结果基本一致。

System Dynamic Modeling on the Valuation of Ecosystem Services in Oriental River Prawn(Macrobrachium nipponense) Aquaculture Ponds

Valuation on ecosystem services has been paid much more attention by researchers,decision-makers and the public in the last ten years.However,most current studies are still based on static evaluation framework,dynamic assessment has been scarcely used.In this paper,using the principle and method of system dynamics,the internal structure of pond aquaculture system evaluation of oriental river prawn(Macrobrachium nipponense) is analyzed and its causality and flow chart diagram is given.Then,the mathematical model of aquaculture system is developed with differential equations and simulated with computer,the trend of changes in 30 years about the value of food provision,O2-emission,carbon fixation and costs of eutrophication at different aquaculture strategies has been forecasted.The result shows that: 1) Regardless of any strategy to be adopted,if the external environment of a system can not change,the supply of net value per year of ecosystem services will be stable.2) Non-market value including O2-emission and carbon fixation is an important and stable source of the value of ecosystem services.3) In a short period,the change of investment on oriental river prawn aquaculture will result in large fluctuations of the market value of the prawn,but in a long time,with the increase of investments,the market value of the prawn will increase,but the rate of the increment will reduce to zero.4) On the constraint of assumptions and environments,the outcome of simulations basically accords with the result of actual measurement.