陕西省耕地转移对生态系统服务价值的影响

Effects of cultivated land transition on ecosystem service value in Shaanxi Province of China

基于效用最大化理论构建土地利用转移的经济学分析框架,利用1990—2015年4期的遥感数据,探讨在生态修复工程以及城镇扩张双重背景下陕西省耕地转移对生态系统服务价值的影响机制。研究发现:陕西省耕地主要向经济刺激下的城乡建设用地和生态修复政策驱动下的生态用地转化。城镇扩张对生态系统服务价值具有显著的负向影响,但其边际效应是林草覆盖率的函数;随着退耕还林工程的实施,林草覆盖率的增加可弥补城镇扩张带来的生态系统服务价值损失;当林草覆盖率达到83.7%时,城镇扩张不会对生态系统服务产生影响,此时为退耕还林工程实施的临界水平。2017年陕西省林草覆盖率为68.83%,在保证基本农田不减少的条件下,今后仍需进一步扩大退耕还林规模,以保证区域生态安全并满足生态文明建设的需要。

This study developed a panel threshold model to examine the impact of cultivated land transition due to urban expansion and ecological restoration project on ecosystem service value,according to the economic analysis framework based on land use/land cover change derived from remote sensing data of 1990-2015 in Shaanxi Province.Cultivated land transition has moved in two opposite directions driven by urban expansion and ecological restoration policy.Urban expansion affects negatively and significantly on ecosystem service value,but its marginal effect is a function of the rate of forest and grassland coverage.With the implementation of the Grain for Green project,forest and grassland coverage increase can make up for the loss of the ecosystem service value caused by urban expansion.The rate of forest and grassland coverage is captured by the panel threshold model,which indicates that when this rate reaches 87.3%,urban expansion has no significant impact on the ecosystem service value.In 2017,the rate of forest and grassland coverage in Shaanxi Province was 68.83%.Therefore it is essential for the province to further expand the scale of returning farmland to forest(grass)to ensure regional ecological security and meet the needs of ecological civilization construction while ensuring that the basic farmlands remain unchanged.