城镇化进程对沙漠化逆转趋势影响的动态计量分析——以宁夏盐池县为例

Dynamic Econometric Analysis of the Relationship between Urbanization and Desertification Reversal Trend:a case of Yanchi,Ningxia,China

以典型沙漠化逆转区宁夏盐池县为例,对2003—2013年城镇化与沙漠化逆转趋势进行综合测度,利用ADF单位根检验、Granger因果检验、脉冲响应函数及方差分解模型就城镇化进程对沙漠化逆转趋势的动态影响进行分析。结果表明:(1)2003年以来,盐池县城镇化水平逐步提高,沙漠化逆转综合指数基本保持在0.3以上。(2)作为人文驱动因素,城镇化综合水平虽不直接对沙漠化逆转趋势产生作用,但其分量指标却对沙漠化逆转趋势及逆转压力的产生、状态的表现和响应的形成产生冲击。(3)从长期预测来看,沙漠化逆转趋势及分量指标受自身冲击的影响随时间的推移而逐渐减小,城镇化对沙漠化逆转的解释能力正在逐步提升,人口迁移、经济增长、社会进步和城镇化发展对逆转趋势、压力、响应和状态的冲击影响分别维持在78%、58%、13%和9%的水平上。未来盐池县城镇化的发展应当以人口城镇化、经济城镇化作为关键突破点,以促进农户非农生计的可持续性,提高城镇化对生态环境的促进作用。

There was complex relationship between urbanization subsystem and ecological environment subsystem in different regions and different phases.This paper explores the interactive process and quantitative mechanism of urbanization and desertification reversal trend during 2003-2013 in Yanchi,a typical area of desertification reversed of Ningxia,China.The paper measures the comprehensive level and dimension of urbanization and desertification reversal with entropy method,examines causal relationships between sub-indexes with ADF stationary test and Granger causality test,and analyzes the dynamic process during 2003-2013 with impulse response and variance decomposition of VAR model.Results showed that：（1）The urbanization level in Yanchi had been gradually increasing since 2003,meanwhile the desertification reversal index remained at more than 0.3.（2）The comprehensive index of urbanization did not directly affect the desertification reversal trend,but its component indicators impacted the desertification reversal trend,pressure,status and response.（3）The explanatory power of urbanization to desertification reversal was gradually improving.Population migration,economic growth,social progress and urbanization development impact on desertification reversal trend,pressure,state,response were maintained at the level of 78%,58%,13%and 9%,respectively.As an effective way to improve the ecological environment of inland arid area,the population urbanization and society urbanization should be regarded as the key breakthrough to enhance the urbanization＇s positive effect to ecological environment in Yanchi County.