天山新疆段及南北麓草地植被覆盖度时空变化特征研究

Research on Temporal and Spatial Variation Characteristics of Grassland VegetationCoverage in the Xinjiang Section of Tianshan Mountains

天山草地分布面积广阔,不仅是新疆畜牧业发展的主要支撑,也在维护生态安全方面具有重要贡献。为了解天山新疆段草地植被覆盖度的动态特征与变化趋势,以2001-2020年MODIS NDVI产品为主要数据源,采用像元二分模型估算植被覆盖度,运用转移矩阵和趋势分析法研究其变化特征,并利用地理探测器模型分析驱动因素。结果表明,研究区草地多年平均植被覆盖度在0.34~0.42波动,主要以中低、中植被覆盖度为主,各等级植被覆盖度大致呈西部高覆盖东部低覆盖的分布特征;从变化趋势来看,研究区草地植被覆盖度总体上有上升趋势,盆地周围覆盖度增加、中部山区其变化基本稳定,增加和基本稳定的区域面积占总面积的10.41%和89.16%;从地理探测器运行结果来看,单因子作用解释最大的是降水量,q为18%,当降水量与海拔交互作用时对研究区草地植被覆盖度的影响更为明显。研究结果可为天山草地生态安全保护与质量评估提供参考依据。

The grassland of the Tianshan Mountains is widely distributed.It is not only the main support for the development of animal husbandry in Xinjiang,but also an important contribution to the maintenance of ecological security.In order to understand the dynamic characteristics and change trends of grassland vegetation coverage in Xinjiang section of the Tianshan Mountains,this study used MODIS NDVI products from 2001 to 2020 as the main data sources,estimated vegetation coverage by using pixel dichotomous model,studied its change characteristics by using transfer matrix and trend analysis method,and analyzed driving factors by using geo-detector model.The results showed that the annual average vegetation coverage of the grassland in the study area fluctuated between 0.34 and 0.42,and the vegetation coverage of each grade was mainly in medium and low levels,with the distribution characteristics of high coverage in the west and low coverage in the east.From the change trend,the coverage of grassland vegetation in the study area generally had an upward trend.The coverage around the basin increased,and the change of vegetation coverage in the central mountainous area was basically stable.The increased and basically stable regional areas accounted for 10.41%and 89.16%of the total area.According to the results of the operation of the geographic detector,the precipitation was the largest explanation of the single factor effect,and the q value was 18%.When the precipitation interacted with the altitude,the impact on the grassland vegetation coverage in the study area was more obvious.The results of this study provides a reference for ecological security protection and quality assessment of the Tianshan Mountains grassland.