生态文明建设下退耕还湿必要性与成效分析——基于博弈和模糊评价视角

Necessity and Effect of Returning Farmland to Wetland:An Analysis Based on Game Theory and Fuzzy Evaluation

退耕还湿既是生态文明建设的要求,又是人们对美好环境向往的时代需求。以退耕还湿的必要性和成效为研究基点,通过主体利益博弈和模糊综合评判来阐明该工程的推行选择和效益发展。政府和农户利益博弈的结果是双方反复博弈后最终会以群体高比例达成最优均衡战略[服从,补偿],从主体层面表明退耕还湿具有必要性;运用AHP-Fuzzy模型对20个具有代表性的湿地因子从经济、社会、生态3方面效益对三江平原湿地进行综合评价,得出各效益最大隶属度分别是3、4、3,综合效益最大隶属度为3,处于潜力发展期,表明退耕还湿的实施有成效,具有较好的发展前景。最后,针对两种方法和结果,给出了相应结论及相关建议。

Returning farmland to wetland is required,both to build an ecological civilization and to meet the demand of people for a beautiful environment.In recent years,implementing the“returning farmland to wetland”policy has buffered the reduction of wetland area and promoted recovery of wetland function.In order to better promote this policy,we analyzed the necessity and effectiveness of returning farmland to wetland based on game theory and fuzzy evaluation.A game using a replicator dynamic framework to model evolution and prestige-biased learning was developed with the government and farmers as players.Participant strategies evolved over repeated rounds of the game and an optimal strategy for the group was eventually selected.The Fuzzy Analytic Hierarchy Process(AHP)model used to evaluate outcomes was based on 20wetland indices representing economic,social and ecological benefits.Sanjiang Plain wetland was selected as the research object,and the fuzzy AHP model was used to evaluate the benefits of policy implementation.The government and farmers were able to reach an Evolutionarily Stable Strategy(ESS)through learning and making adjustments as they played round after round of the game.Eventually the optimal equilibrium strategy,using a combination of compensation(carrots)and punishment(sticks),was attained by a high proportion of the participants.The results of the game indicated that returning farmland to wetland was necessary.The accrual of economic,social and ecological benefits,according to the fuzzy AHP model,showed that the maximum membership of each benefit was 3,4,and 3,respectively,and the maximum membership of the comprehensive benefit was 3.The increase in social benefits after returning farmland to wetland was significant and began to accrue immediately.The economic and ecological benefits were moderate because these benefits accrue over extended periods of time.Overall,the prospect is good for returning farmland to wetland and the policy could be effective.To increase the chances for effective policy implementation,we offer three recommendations:(1)increase the level of compensation and the severity of punishment,(2)establish a profit-loss accounting system to promote long-term cooperation,and(3)promote the development of social benefits,such as recreation/education facilities at newly recovered wetlands.The methods developed in this study,the replicator dynamic game with fuzzy AHP evaluation of benefits,have excellent potential for objectively and effectively implementing the policy of returning farmland to wetland.