PPP模式：乡村环境治理中多元主体共生的新选择

推进美丽乡村建设、补齐乡村环境治理短板是全面建成小康社会的硬任务， PPP模式的引入为乡村环境整治提供了新途径。以共生理论为基础引入演化博弈分析框架，对不同场景下乡村环境治理的三方（地方政府、社会资本、村民）共生条件进行探索，并结合现实案例检验基本结论，结果发现：PPP模式高度依赖政府的有效治理，特别是各级政府的有效监管对达成多方共生非常关键；政府的有效监管、社会资本守约的交易成本和村民在环保治理过程中受益是三方共生的基础，而设计合理的惩罚机制可以减少政府失职和资本方的违约动机，博弈结果将趋于三方共生。同时发现，在监管缺失的情况下，社会资本守约和村民参与恒不成立；村民参与环境治理取决于参与的净收益，与受到的政府奖励无关。由此，可以通过改革乡村治理方式、加强政府有效监管、采取第三方定价和构建风险补偿机制、以村民受益为核心加快乡村组织建设、发挥村民主体作用等措施，不断推进乡村环境的治理。

PPP Model: A New Choice for the Coexistence of Multiple Subjects in Rural Environmental Governance

Promoting the construction of beautiful countryside and supplementing the shortcomings of rural environmental governance are the hard tasks of building a well-off society in an all-round way. The introduction of the PPP model provides new options for rural environmental improvement. This article based on the evolutionary game analysis framework, and the symbiosis theory, analyzes the symbiotic conditions of the three parties (local government, social capital, villagers) in rural environmental governance in different scenarios, and tests the basic conclusions with realistic cases. The research suggests that the PPP model is not a panacea, and is highly dependent on the effective governance of the government, and the effective supervision of governments at all levels is especially critical to achieving multi-party symbiosis. Tripartite symbiosis needs to be based on effective government supervision, reduction of the cost of non-compliance with social capital, and benefits to villagers. Also, designing a reasonable punishment mechanism can reduce government inaction and social capital breaches. The evolutionary result will tend to be tripartite symbiosis. Under the circumstances, the compliance of social capital and the permanent participation of villagers are not established; the participation of villagers in environmental governance depends on the net income of participation and has nothing to do with the government rewards received. On this basis, we put forward suggestions for reform of governance methods, improvement of supervision, and for the introduction of third-party pricing and risk compensation mechanisms in order to accelerate the construction of rural organizations and to implement village democracies for rural environmental governance.