水热条件和人类活动对山西省植被覆盖变化的影响

基于山西省1999—2010年的SPOT Vegetation数据及气象资料,运用Sen趋势度+Mann—Kendall法、残差分析法和相关分析法,对山西省近12a植被覆盖的时空变化进行了分析,探讨了水热条件与人类活动对植被覆盖变化的影响。从年际变化来看,1999—2010年山西省生长季植被NDVI呈现显著上升趋势,其增加速率为0.199 4/a;从空间格局来看,大部分地区NDVI有增加趋势,其中极显著增加的区域占72.94%,主要分布在山西省的黄土丘陵沟壑区及山区;NDVI减少区域极小,仅占0.21%,呈不均匀零星分布。降水量与生长季NDVI的相关性较高,从整体上呈现出由北向南逐渐减少的特点,其中98.54%的区域呈正相关关系;此外,气温与生长季NDVI的相关性较低,平均相关系数仅为-0.415。人类活动对山西省植被覆盖变化的正面和负面作用并存,但正影响远大于负影响,说明近年来退耕还林草以及水土流失治理的生态效益正在显现。

Influence of Hydrothermal Condition and Human Activities on Dynamics of Vegetation Coverage in Shanxi Province

Base on the SPOT Vegetation and meteorological data from 1999 to 2010, the spatial and temporal variations of vegetation cover in Shanxi Province were analyzed by the methods of Sen+Mann-Kendall, residual analysis and correlation analysis to discuss the effects of hydrothermal condition and human activities on dynamics of vegetation coverage. The results showed that, from the perspective of the interannual variation, the vegetation coverage in Shanxi Province presented a significant increasing trend and the growth rate reached 0.199 4/a during 1999-2010. From the perspective of the spatial pattern, the NDVI had an increasing trend in most of the study area. The significant increasing areas located mainly in the loess hilly-gully region and mountains in Shanxi Province, which accounted for 72.94%; the areas where the NDVI reduces ws distributed sporadically, which only accounts for 0.21%. The change of vegetation coverage had great correlation with precipitation, and on the whole, it showed an obvious feature that gradually reducing from north to south, among them, the areas where the correlation coefficient was positive accounts for 98.54%; besides, the change of vegetation coverage had little correlation with temperature, and the average correlation coefficient was only -0.415. In addition, the impact of human activities on the vegetation cover change in Shanxi Province was double-edged sword, but positive influence was far greater than negative effect, which indicates that returning the grain plots to forestry and soil erosion controlling brought an important ecological benefit role in recent years.