2000—2020年鄂尔多斯市植被NDVI变化格局及归因分析

处于农牧交错区的鄂尔多斯市生态系统较为敏感,为探究全球气候变化以及人类活动对鄂尔多斯市生态系统的影响,利用MOD13Q1 NDVI数据以及同期气象数据,分析了鄂尔多斯市2000—2020年植被NDVI变化特征,并利用偏相关分析法以及残差驱动力分析法对引起植被NDVI变化的气候和人为因素进行了分析。结果表明:(1)21年来鄂尔多斯市植被NDVI总体呈现上升趋势,植被改善明显,全市68.66%的区域植被NDVI得到改善,西南部改善幅度小于东北部;(2)鄂尔多斯市植被NDVI与气候因子偏相关性存在明显的地区差异,植被NDVI与降水的偏相关性较高,降水与温度共同影响的区域约占总面积的2.27%;(3)鄂尔多斯市植被受到人类活动与气候的共同影响,21年来人类活动对鄂尔多斯市植被NDVI变化起到主导作用,其平均贡献率为82.67%,气候变化对植被NDVI生长的影响主要体现在降水因素上。人类对鄂尔多斯市的植被影响具有两面性,城市建设对植被的生长起到制约作用,生态工程的实施则有利于植被的生长;(4)2000—2020年鄂尔多斯市以NDVI表征的植被覆盖度的增加与人类活动密不可分,但是同时鄂尔多斯地区气候条件对植被生长有很大的限制作用,实施生态工程中要切实注意到气候变化所带来的影响,切不可盲目扩大生态工程,对于毛乌素沙地等地区植被需要实行人工保护,使其形成稳定生态系统。

Analysis on Change Pattern and Attribution of Vegetation NDVI in Ordos City from 2000 to 2020

The ecological system of Ordos City, located in agro-pastoral ecotone, is more sensitive. In order to explore the impact of global climate changes and the human activities on the ecosystem of Ordos City, we used MOD13Q1 NDVI, meteorological data, the partial correlation analysis and residual driving force analysis methods to analyze the change characteristics and driving force for vegetation NDVI of Ordos City from 2000 to 2020. The results show that:(1)the vegetation NDVI of Ordos City had shown an overall upward trend in the past 21 years, and the vegetation had improved significantly; the vegetation NDVI of 68.66% of the city had been improved, and the improvement rate of vegetation in the southwest was smaller than that in the northeast;(2)there were obvious regional differences in the partial correlation between vegetation NDVI and climatic factors in Ordos City; the partial correlation between vegetation NDVI and precipitation was relatively high, and the area affected by precipitation and temperature together accounted for about 2.27% of the total area;(3)the vegetation of Ordos City was affected by both human activities and climate change; in the past 21 years, human activities played a leading role in the change of vegetation NDVI in Ordos City with an average contribution rate of 82.67%; the main influence of climate change on the growth of vegetation NDVI was the precipitation; the impact of humans on the vegetation of Ordos City had two sides; urban construction restrict the growth of vegetation, and the implementation of ecological projects was conducive to the growth of vegetation;(4)from 2000 to 2020, the increase of vegetation coverage represented by NDVI in Ordos City was inseparable from human activities, but at the same time, the climatic conditions in the Ordos region had a great restrictive effect on the growth of vegetation; when implementing ecological projects, we must pay attention to the impact of climate change, and must not blindly expand ecological projects; the vegetation in areas such as the Mu Us desert needs to be artificially protected to form a stable ecosystem.