中国城市生态效率测定及其时空动态演变

Measurement and temporal-spatial dynamic evolution of urban eco-efficiency in China

基于2003—2015年间我国285个地级及以上城市的面板数据,运用超效率SBM模型测算我国城市生态效率,在时间对比分析和空间相关性分析的基础上,构建传统和空间马尔可夫链转移概率矩阵,对城市生态效率的时空演变格局进行对比分析,并探讨城市生态效率时空动态演变特性。实证结果显示:(1)在时间演变过程中,城市生态效率整体上呈现逐渐上升走势,城市生态向集约型转变取得一定的成效,中西部生态效率较高的城市的增量多于东部城市,中西部城市生态效率提升显著,而东部城市生态效率整体上出现下降。(2)全局Moran’sⅠ指数值均为正,即我国城市生态效率在空间分布上呈显著的正相关性,并表现出空间集聚特性,近邻效应显著。(3)将城市生态效率划分为4个相邻但不相互交叉的完备区间,传统的马尔可夫链转移概率矩阵显示,城市生态效率向高水平方向转移的趋势显著,城市生态效率的演变具有维持原有状态的稳定性,且较难实现跨越式转移。(4)引入空间滞后的空间马尔可夫链转移概率矩阵显示,地理区位背景对城市生态效率时空演变转移的影响显著,在空间分布上具有波动性的集聚现象,相邻城市之间生态效率的影响是相互的,且在空间上呈现集聚的格局,生态效率较高城市带动邻近城市生态效率向上转移的可能性更大,具有正向溢出效应,呈现出"高者恒高、低者仍低、高带动低、低抑制高"的俱乐部趋同现象。最后,分析当前研究存在的不足及改进的方向,并提出相关启示和建议,包括出台更加严格的资源环境政策、加强城市生态合作与交流、借鉴邻近生态效率高的城市生态环境管理经验等。

Based on the panel data of 285 prefecture level cities and above in China from 2003 to 2015,the super efficiency model(SBM)has been used to measure the urban eco efficiency.Based on the time comparison analysis and spatial correlation analysis,the temporal spatial evolution pattern of urban eco efficiency has been analyzed by constructing traditional and spatial Markov chain transition probability matrix,and then this paper discusses its dynamic evolution characteristics.The results show that:①The urban eco efficiency shows a gradual upward trend as a whole,and it has achieved some success through shifting to intensive mode during the time evolution process.The amount of cities with higher eco efficiency in the central and western regions increased more than those in the eastern cities,which means that the urban eco efficiency of central and western cities increased significantly,while the overall urban eco efficiency of eastern cities decreased.②The global Moran’s I index values are positive,which means the spatial distribution of urban eco efficiency shows a significant positive correlation,and shows spatial clustering characteristic with significant neighbor effect.③This paper divides four adjacent but not intersect complete ranges based on the urban eco-efficiency.As the traditional Markov chain transition probability matrix shows that,the trend of urban eco-efficiency transferred to high level is remarkable,and its evolution had the stability to maintain with the original state,which is difficult to achieve the leap forward transfer.④The spatial Markov chain transition probability matrix introduced into spatial lag shows that,the geographical location background has a significant effect on the temporal spatial evolution of urban eco efficiency,and has a fluctuating clustering phenomenon in spatial distribution.The influence of eco efficiency among adjacent cities is mutual and presents an agglomeration pattern in space,and the higher eco efficiency city drives the nearby cities to upward transfer more likely to have a positive spillover effect,showing a‘club convergence’phenomenon of‘high constant high,low still low,high drive low,low restraint high’.Finally,this paper also analyzes the shortcomings and direction of improvement in current research,and put forward relevant policy suggestions,including more stringent resource and environment policies,strengthening urban ecological cooperation and exchange,drawing on the experience of urban ecological environment management with higher eco-efficiency in neighboring cities and so on.