退耕还林(草)过程中陕北地区NDVI时空变异及其驱动因子的地理探测  

Spatio-temporal variation of NDVI and geographical detection of its driving factors in the‘Grain for Green’project in northern Shaanxi

作　　者：尚雪 何钊全 张铜会 SHANG Xue;HE Zhaoquan;ZHANG Tonghui(Network and Information Center,Yan'an University,Yan'an 716000,China;School of Life Sciences,Yan'an University/Yan'an Key Laboratory of Ecological Restoration,Yan'an 716000,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]延安大学网络信息中心,延安716000 [2]延安大学生命科学学院/延安市生态恢复重点实验室,延安716000 [3]中国科学院西北生态环境资源研究院,兰州730000

出　　处：《生态科学》2022年第1期66-76,共11页Ecological Science

基　　金：国家自然科学基金项目(41371053,30972422,51669034,51809224);国家重点研发计划(2017YFC0506706,2017YFC0504704);陕西省教育厅重点实验室项目(20JS150);博士科学研究启动项目(205040305)。

摘　　要：地表植被作为生态环境变化的敏感因子,对维持区域生态稳定性具有重要作用。基于退耕还林(草)生态工程实施过程中2000-2019年陕北地区的MODIS NDVI数据,结合地形、地貌、气候、土壤和植被等环境因子,探究NDVI时空变异特征,并运用地理探测器模型对植被NDVI影响因子及其影响程度进行探测,最终确定主要环境因子对NDVI的驱动机制。结果表明:(1)2000-2019年陕北地区中高和高植被覆盖区面积分别增加了25.64%和11.74%,植被覆盖状况整体良好;NDVI空间分布差异显著,其中,东南丘陵沟壑区植被覆盖度较高,西北风沙区以及城镇建设用地区域植被覆盖度较低;(2)陕北地区植被NDVI主要受年降水量和干燥度指数的影响,其解释力均大于45%;植被类型、≥10℃积温、地貌类型和坡度的解释力在15%-35%之间;土壤类型、年均温、高程和坡向的解释力均小于10%;(3)各环境因子对陕北地区NDVI变化的影响存在相互增强和非线性增强的协同交互关系。结果揭示的中高和高植被覆盖区面积的显著增加、影响NDVI的主要驱动因子年降水量和干燥度指数的适宜阈值以及它们之间交互增强的驱动机制,能够为陕北地区生态脆弱区生态环境修复提供理论支撑和辅助决策。As a sensitive factor of ecological environment change, surface vegetation plays a vital role in maintaining regional ecological stability. Based on MODIS NDVI data of northern Shaanxi from 2000 to 2019 in the ‘Grain for Green’ project, through combination of environmental factors, such as topography, geomorphology, climate, soil and vegetation, the spatio-temporal variation characteristics of NDVI were explored, and the influence factors of NDVI and its influence degree were detected by using the geographical detector model for determining the driving mechanism of the main environmental factors on NDVI. The results showed that:(1) the area of medium and high vegetation coverage in northern Shaanxi increased by 25.64%, 11.74%, from 2000 to 2019, respectively. Significant difference of the spatial distribution of NDVI occurred, among them, the vegetation coverage was higher in the southeast hilly and gully region, and was lower in the northwest wind-sand region and urban construction land area.(2) NDVI of vegetation in northern Shaanxi was mainly affected by annual precipitation and dryness index, of which explanatory power exceeded 45%. The explanatory power of vegetation type, accumulated temperature of ≥10 ℃, geomorphic type and slope was from15% to 35%. The explanatory power of soil type, annual average temperature, elevation and slope direction was less than 10%.(3) Tahe influence of various environmental factors on NDVI of vegetation in northern Shaanxi was mutually enhanced and was non-linear enhanced. Therefore, the significant increase in the area of medium and high vegetation coverage, the appropriate threshold of the main driving factors(annual precipitation and dryness index) affecting NDVI, and the driving mechanism of their interaction enhancement revealed in our study can provide theoretical support and auxiliary decision-making for ecological environment restoration in the ecological fragile areas of northern Shaanxi.

关 键 词：植被NDVI 地理探测器 时空变化 驱动力 陕北地区 

分 类 号：S157.2[农业科学—土壤学]