基于条件风险价值的两阶段随机规划模型在草地生态系统恢复中的应用--以三江源区为例

A conditional value-at risk-based two-stage stochastic programming model for grassland ecosystem restoration——A case study for the three-river source

以三江源草地生态系统为例,构建了基于条件风险价值的两阶段随机规划模型,通过综合考虑环境需求、水土流失、治理成本等若干因素,对三江源区4个州的超载畜牧面积、草地修复面积进行优化分析,对超载带来的损失、修复带来生态效益增加及成本增加进行了核算,为三江源区的生态恢复与管理提供了理论依据.本文的优化分析结果表明,草地超载畜牧面积以及由此带来的损失随着随机水平的增加而减少.此外,三江源区的生态经济收益将随着风险因子值增加而减少,决策者所持风险态度对生态恢复方案的制定起着决定性影响.优化结果有助于决策者在经济效益与系统风险之间进行权衡,建议将减少牲畜总量作为草地恢复和治理的主要目标,同时发展生态畜牧业以促进草地生态与畜牧业协调发展.同时,建议相关地区进一步完善畜牧业生态补偿机制,协调好地区经济发展与生态系统保护之间的关系.

Taking three-river source grassland ecosystem as an example,a conditional value-at risk-based two-stage stochastic programming model was proposed for grassland ecosystem restoration.Overload area and restoration area of grassland ecosystem in the three-river source region can be optimized with consideration of environmental requirements,soil erosion and restoration cost.Loss of overload,increased ecological benefit and additional cost of restoration can be evaluated,which will provide theoretical basis for grassland ecosystem restoration and management in three-river source region.Results indicate that overload area and loss of overload will decrease with the stochastic level increase.The total ecological benefit of grass ecosystem will decrease with risk level decrease,indicating that risk attitudes of decision-makers play a decisive role in developing sustainable ecological management schemes.The obtained results can be helpful for decision makers to balance the conflicts between ecological benefit and system risk.Reducing the total amount of livestock should be taken as the main goal of grassland ecosystem restoration and management,while ecological stockbreeding should be developed to promote sustainable development of grassland ecosystem and livestock.Besides,compensation mechanism in related areas should be refined to coordination the relationships between economic development and ecosystem conservation.