【摘要】 乌珠穆沁草原是我国北方典型优良草原，承担着防风固沙的重要功能，是维护区域生态安全的关键屏障。为明确该地区草地植被情况，以东、西乌旗为研究区，基于MODIS13Q1数据，采用像元二分模型反演2000-2023年生长季植物覆盖度（FVC），结合Sen+MK趋势分析和偏相关分析法，揭示FVC时空变化特征及其对气候因子的响应。结果显示：（1）2000—2023年乌珠穆沁草原FVC多年平均值为55.92%，整体呈上升趋势，变幅为18.47%～69.44%，最低值、最高值分别出现在2007年和2012年；（2）空间上，FVC自西向东递增，整体呈改善趋势，改善区域广泛连片，退化区域集中于西乌珠穆沁旗（西乌旗）东部；（3）植被覆盖结构稳定，1级和2级植被累计占比常年超65%,3级植被年际波动显著（变幅1.01%～20.41%）,4、5级低覆盖植被占比常年低于18%;(4)FVC与降水整体呈显著正相关（正相关区域占88.53%），降水对植被生长具有明显促进作用，FVC与气温总体呈不显著相关（不显著相关区域占70.31%），气温升高对部分区域植被生长存在抑制效应，主要集中于东乌珠穆沁旗（东乌旗）东部及西乌旗大部分地区；（5）气候变化是FVC变化的主导因素，显著贡献区域占77.07%，人类活动贡献较弱，显著贡献区仅占3.08%，负贡献区占34.87%，主要分布于西乌旗中东部地区。更多还原

【Abstract】 The Ujinmqin Grassland is a typical high-quality grassland in northern China, playing a critical role in windbreak and sand fixation and serving as a key barrier for regional ecological security. To assess the vegetation conditions in this area, the study focused on East and West Ujinmqin Banners. Using MODIS13Q1 data and the pixel dichotomy model, the fractional vegetation cover(FVC) during the growing seasons from 2000 to 2023 was retrieved. Combined with Sen+Mann-Kendall(MK) trend analysis and partial correlation analysis, the spatiotemporal variation of FVC and its response to climatic factors were examined. The results are as follows.(1) From 2000 to 2023, the multi-year average FVC of the Ujinmqin Grassland was 55. 92%, showing an overall increasing trend, with values ranging from 18. 47% to 69. 44%. The minimum and maximum FVC occurred in 2007 and 2012, respectively.(2) Spatially, FVC increased from west to east, exhibiting an overall improvement trend, with improvement areas forming large contiguous patches, while degradation areas were concentrated in the eastern part of West Ujinmqin Banner.(3) The vegetation cover structure is relatively stable, with levels 1 and 2 vegetation consistently accounting for over 65% of the total area. Level 3 vegetation exhibits significant interannual fluctuations(ranging from 1. 01% to 20. 41%), while levels 4 and 5, representing lowcoverage vegetation, consistently account for less than 18% of the area.(4) FVC shows a significant positive correlation with precipitation overall(88. 53% of the area), indicating that precipitation strongly promotes vegetation growth. The correlation between FVC and temperature is generally not significant(70. 31% of the area), though rising temperatures inhibit vegetation growth in certain regions, mainly in the eastern part of East Ujinmqin Banner and much of West Ujinmqin Banner.(5) Climate change is the dominant factor driving FVC variation, with regions of significant contribution accounting for 77. 07%. Human activities play a relatively minor role, with areas of significant contribution only accounting for 3. 08%, while negative contribution regions account for 34. 87%, mainly distributed in the central and eastern parts of West Ujinmqin Banner.更多还原