河北坝上地区植被覆盖演化特征及其风险评估

Evolution Trend of Vegetation Coverage and Its Risk Assessment in the Bashang Region in Hebei Province

坝上地区作为京津冀阻滞风沙入侵的生态屏障和水源涵养地,是构筑首都经济圈生态安全,维持地方经济、社会和环境协调发展的重要保障。基于MODIS NDVI遥感数据,采用趋势线性分析、稳定性分析、变标度极差分析等数理方法,反演2005—2015年坝上地区植被覆盖时空演变趋势和稳定性,在此基础上预测植被演化趋势并进行风险评估。结果表明：（1）11 a间坝上地区植被覆盖度区域差异性比较明显,整体表现为从坝西到坝东依次递增的空间分布特征。（2）坝上地区植被覆盖度极显著改善区域和显著改善区域的面积最大,占研究区总面积的65.89%,未显著改善区域占32.28%,退化区域占1.82%。（3）坝上地区植被覆盖稳定性整体表现为东高西低。高稳定度区域和较高稳定度区域占比最大,为61.32%,中稳定度区域占24.35%,低稳定度和较低稳定度的区域占14.33%。（4）坝上地区未来植被覆盖持续改善区域占59.48%,潜在退化占38.67%,持续退化占1.04%,潜在改善占0.82%。

As an ecological barrier for preventing the invasion of wind-blown sand and a major water source in Beijing,the Bashang region in Tianjin and Hebei Province is significant for constructing the ecological security in capital economic circle and for achieving the coordinated development of the economy,society and environment. In this study,the MODIS NDVI remote sensing data were analyzed,and the spatiotemporal change of vegetation coverage in the Bashang region during the period of 2005-2015 was identified. The analysis methods used in the study included the linear regression,coefficient of variation,R/S analysis and other mathematical methods. The results are as follows：（1） The regional difference of vegetation coverage was obvious in the Bashang region over the past 11 years,and the vegetation coverage increased from the west to the east;（2） Area of the regions with the very significant improvement and significant improvement of vegetation coverage was the largest and occupied 65. 89% of the total study area. Areas of the regions with insignificant improvement of vegetation coverage and with vegetation degeneration occupied 32. 28% and 1. 82% respectively;（3） The holistic stability of vegetation coverage was high in the east but low in the west. The area of the regions with high stability and relatively high stability of vegetation coverage was the largest and occupied 61. 32%. The areas of the regions with medium stability and relatively low stability of vegetation coverage occupied 24. 35% and 14. 33% respectively;（4） In the future,the areas of the regions with continuous improvement of vegetation coverage,potential vegetation degeneration,continuous vegetation degernation and potential improvement of vegetation coverage would occupy 59. 48%,38. 67%,1. 04% and 0. 82%respectively.