三峡库区植被覆盖时空变化特征及归因分析

Spatiotemporal Variation Characteristics and Impact Factors of Vegetation Coverage in the Three Gorges Reservoir Area

采用趋势分析探讨了三峡库区植被NDVI(Normalized Difference Vegetation Index)时空变化格局及与海拔的关系;通过Mann-Kendall检验对NDVI变化的突变点进行了识别;通过相关分析明确了区域NDVI与气候、人文因素间的关联性和驱动分区.结果表明:(1)2000~2019年区域NDVI均值呈波动上升趋势,空间分布异质性明显,且随海拔上升呈先增加后略微降低的趋势;(2)2000~2008年NDVI增加趋势较明显,2009年以后放缓;(3)以气候为主要影响因素的区域仅占研究区面积的8.9%,人类活动是区域NDVI变化的重要因素.其中,退耕还林等生态工程具有正向作用,城镇化对经济发展起着负向作用,亟需采取相应措施以实现区域经济-生态系统良性互动.

Trend analysis was used to explore the spatial and temporal patterns of vegetation normalized difference vegetation index(NDVI) in the Three Gorges Reservoir Area(TGRA) and its relationship with elevation.Through Mann-Kendall test, the mutation points of NDVI change was identified.The correlation and its driving partition of regional NDVI and climate, human factors were clarified.The results show that:(1) From 2000 to 2019,the average NDVI in the TGRA showed a rising trend of fluctuation, and its spatial distribution heterogeneity was obvious, which shows a increase first and then decrease slightly with regional elevation rising;(2) The increasing trend of NDVI was obvious from 2000 to 2008,and its growth rate slowed down after 2009;(3) Areas where climate was the main factor affecting NDVI accounted for 8.9% of the total research area, whereas human activities were the primary factor influencing NDVI changes.Among them, ecological projects such as returning farmland to forests have a positive effect, while urbanization and economic development have a negative effect.It is urgent to take corresponding measures to realize the benign interaction between the regional economy and the ecosystem.