不同土地利用方式下的七里海湿地临界评价研究

在"湿地临界"概念的基础上,定性分析了湿地利用与保护的平衡状态,探讨了不同利用方式下的湿地临界的研究步骤,并从基于耕地和河蟹养殖地两种土地利用方式入手,对七里海湿地临界进行了评价。研究表明,通过建立湿地临界模型,从经济效益评价和生态效益的评估入手,对湿地资源利用与保护进行临界分析,可以较好的反映湿地利用的临界状态;采用该方法,七里海湿地耕地利用的年净收益为9 5941.42元/hm2,净损耗为18 072.75元/hm2,临界效益(△B)值为77 868.67元/hm2;养殖河蟹的年净效益为21 622.68元/hm2,净损耗为2 0274元/hm2,△B值为1 348.68元/hm2,说明在目前的社会经济发展水平下,耕地和养殖河蟹两种利用方式尚未超出开发利用的临界准则,七里海湿地仍然具有开发潜力。

Assessment on Critical Criteria of Qilihai Wetland for Different Exploitation

Based on the concept of"wetland criticality",the qualitative analysis was made in this paper to research on wetland exploitation and reservation optimization,and then the research procedures on the critical criteria of different kinds of used wetland.On the basis of the analyses of the use of cultivated land and the farming of river crab,the paper makes an assessment on criteria of Qilihai Wetland.The theory of exploitation and preservation of Qilihai Wetland means that the net marginal earnings of wetland should not be less than the net marginal losses when wetland is exploited.It can be defined as the equilibrium of utilization and reservation.This theory consists of ecological criteria,economical criteria and social criteria.Ecological criteria means that the basic constraint of economical and social criterion is usually seen as the dynamic constraint.The three aspects are not independent but interactive and restricted mutually,so they form an entirety that should not be separated.This passage also made a preliminary study of utilization and protection criticality of Qilihai Wetland from the perspective that the wetland was used as cultivation and raising crabs.By estimating the value of ecosystem service,the outcome of earnings and losses were calculated by means of the analysis on compatibility of each ecosystem service.The result showed that the way to establish a critical model of wetland and the analysis of economical benefit and ecological benefit could reflect the situation of wetland(utilization of critical situation by analyzing the criticality of wetland used and reserved resource).The net earnings of farmland were 2 231 798.42 yuan/hm2 and the net losses were 18 072.75 yuan/hm2,so the value of ΔB,which was the criteria of exploitation and preservation limitation,was 2 213 725.67 yuan/hm2.The net earnings of crab were 21 622.68 yuan/hm2 and the net losses were 20 274 yuan/hm2,so the value of ΔB,was 1 348.68 yuan/hm2.The preliminary study showed that Qilihai Wetland,exploited as cultivation and raising crab,is not overstepped under the circumstances of current social and economic development and Qilihai Wetland could be exploited potentially in the future.