黄土高原植被覆被时空动态及其影响因素

为探究黄土高原植被覆被时空分布与动态变化及其与气候和人类活动的响应机制，基于趋势分析、偏相关性分析和残差分析等方法，利用2000—2015年黄土高原MODND1T/NDVI植被遥感数据、同期气象数据及ESA CCI-LC植被覆被分类数据，根据气候和人为因素对植被覆盖变化的驱动贡献，(1)分析了黄土高原NDVI分布格局、变化趋势及其驱动因素。结果表明：(1)黄土高原NDVI由西北向东南呈递增趋势，具有明显空间异质性分布特征。16年间NDVI呈显著增加趋势，平均递增速率0.010 2/a,波动范围介于0.54～0.71。(2)黄土高原NDVI变化趋势与降水有较强相关性，两者偏相关系数为0.53。(3)黄土高原不同季节NDVI均呈整体增长趋势，春季NDVI与降水呈显著正相关关系，降水是决定春季所有植被类型覆盖变化的最直接因素。(4)残差分析表明，人类活动对黄土高原NDVI的波动影响较大，是黄土高原植被覆盖变化的重要驱动因素。综上，黄土高原16年间植被覆被明显增加，降雨是黄土高原植被生长发育的主要限制因素，人类活动通过退耕还林等生态修复措施对黄土高原植被覆被带来明显改善。

Temporal and Spatial Dynamics of Vegetation Cover on the Loess Plateau and Its Influencing Factors

MODND1T/NDVI vegetation remote sensing data, contemporaneous meteorological data, and ESA CCI-LC vegetation cover classification data from 2000 to 2015 were used to investigate the spatial and temporal distribution and dynamic changes of vegetation cover on the Loess Plateau and its response mechanism to climate and human activities. The Loess Plateau's NDVI distribution patterns, change trends, and their driving variables were spatialized and studied based on the contributions of climatic and anthropogenic factors to changes in vegetation cover. The results showed that:(1)the NDVI of the Loess Plateau increased from the northwest to the southeast, with clear spatially uneven distribution characteristics; the NDVI during the past 16 years demonstrated a substantial upward trend, with a mean rate of increase of 0.010 2/a and a variation range of 0.54 to 0.71;(2)with a partial correlation coefficient of 0.53, the NDVI trend of Loess Plateau was highly connected with precipitation;(3)the NDVI of the Loess Plateau increased in all seasons, and the NDVI of spring was strongly and positively linked with precipitation, with precipitation being the greatest direct influence in determining the cover changes of all vegetation species in spring;(4)the residual analysis revealed that human activities had a significant effect on the fluctuation of NDVI in the Loess Plateau, which was a key driver of vegetation cover change in the Loess Plateau. In summary, the Loess Plateau's vegetation cover had increased significantly over the last 16 years, and precipitation is the main limiting factor for the Loess Plateau's vegetation growth and development. Through ecological restoration measures such as ‘Grain for Green', human activities have significantly improved the vegetation cover of the Loess Plateau.