鄱阳湖生态经济区成立前后NDVI时空动态变化及其驱动因素

鄱阳湖生态经济区是中部地区正在加速形成的增长极之一,研究其植被变化特征可以为鄱阳湖生态经济区更合理的调控经济发展与生态保护提供支持。本研究基于2000-2017年MODIS NDVI,采用最小二乘法斜率探讨生态经济区成立前后NDVI时空变化特征,并借助相关性分析定量化研究气候因素和人为因素对NDVI变化的驱动作用。结果表明:生态经济区成立前(2000-2008年)和成立后(2009-2017年),区域植被覆盖整体均呈现增长趋势。生态经济区成立前NDVI变化趋势为0.05210 a^-1(P<0.05),成立后NDVI变化趋势为0.02510 a^-1(P<0.05),成立后NDVI增长出现放缓现象;空间上,成立前植被发生退化的区域主要分布在地级市和省会周围;成立后,省会和中心城市周围植被退化现象进一步加剧,同时湖区周围、区域北部以及南部农耕区植被也出现退化现象;在影响因素方面,在全区域尺度上,气候因素是NDVI变化的主导因素,气温对NDVI影响大于降水;在NDVI显著变化的区域,人类活动则是影响NDVI变化的主要因素;生态经济区成立前,城市化进程的加快是引起区域植被退化的主要人为活动因素,而生态经济区成立后,农耕区和湖区植被退化、非农建设用地占用其他类型土地、农村宅基地占用草地是区域植被退化的重要人为活动因素。

Spatial and temporal dynamics and its driving factors of vegetation cover before and after the establishment of Poyang Lake Eco-economic Zone

Poyang Lake Eco-economic Zone is one of the accelerating poles of growth in central China. Understanding vegetation changes will provide support for more reasonable regulation and control of economic development and ecological protection in the Eco-economic Zone. Based on MODIS NDVI from 2000 to 2017,we explored the temporal and spatial characteristics of NDVI before and after the establishment of the Eco-economic Zone by using the slope of least square method and quantitatively examined the effects of climate and human factors on NDVI changes by means of correlation analysis. The results showed that before(2000-2008) and after(2009-2017) the establishment of the Zone,the overall vegetation showed an increasing growth trend.The NDVI growth showed a trend of 0.052 10 a^-1(P<0.05) and 0.025 10 a^-1(P<0.05) before and after the establishment of the Eco-economic Zone,respectively. After the establishment of the Eco-economic Zone,the growth of NDVI slowed down. Spatially,vegetation degradation occurred around prefectural cities and the provincial capital before the establishment of Eco-economic Zone,which intensified after its establishment. Furthermore,after the establishment of the Zone,vegetation degradation expanded to area around the lake,northern region and southern farming areas. In terms of influencing factors,on the regional scale,climatic factors were the dominant factors for NDVI change,with the influence of temperature on NDVI being greater than that of precipitation. In areas where NDVI changed significantly,human activities were the main factors affecting NDVI changes. Before the establishment of the Eco-economic Zone,the acceleration of urbanization was the main human factor causing the regional vegetation degradation. After the establishment of the Eco-economic Zone,vegetation degradation in the farming and lake areas,non-agricultural construction land occupation of other types of land,and rural homestead occupation of grassland were important anthropogenic factors inducing regional vegetation degradation.