青藏高原不同季节植被NPP空间分异的定量归因

对人类活动量化中考虑区域生态条件的差异，基于季节尺度，利用潜在NPP与实际NPP计算HAII,选取植被类型、高程、坡度等7个自然因子与HAII进行空间分异探测分析，以更细的季节尺度揭示多因子的影响规律。结果表明：在描述青藏高原人类活动对植被NPP的空间分异影响方面，HAII的解释力与显著性均优于人类活动值，其解释力最高为0.714。在多因子影响植被NPP空间分异方面，自然与人为因子均表现出明显季节差异，夏季人类活动解释力最高，春、秋季减弱，冬季则主要受自然因子影响。其中，坡度、温度、法向直射辐射量与散射辐射量在春、秋、冬季表现出单一的驱动影响，植被生存条件较好的夏季，因子出现明显拐点，降水因子的限制阈值随季节变化。因子交互作用中，人类活动、降水、气温及植被类型4个因子之间产生的交互作用是影响青藏高原NPP的主要驱动力。综合人类活动及多个自然因子，在青藏高原植被生态工程建设中，需主要考虑人类活动、降水、气温及植被类型4个因子，各季节主导因子不同。在干旱少雨地区，人类活动应被重点考虑。研究结果可为不同植被生境条件下的区域提供生态系统管理的参考依据。

Quantitative Attribution of Spatial Variability of NPP in Different Seasons of Qinghai-Tibet Plateau

The human activity impact index (HAII) was calculated based on the potential NPP and the actual NPP. Seven natural factors, such as vegetation type, elevation and slope, were further selected and analyze the spatial differentiation combined with HAII, so as to reveal the influence rules of multiple factors at a more detailed seasonal scale. The results showed that the explanatory power and significance of HAII were better than that of human activities in describing the spatial differentiation of vegetation NPP in the Qinghai-Tibet Plateau. In terms of the spatial differentiation of NPP affected by multiple factors, both natural factors and man-made factors showed obvious seasonal differences. The explanatory power of human activities was the highest in summer, weakened in spring and autumn, and was mainly affected by natural factors in winter. Among them, slope, temperature, normal direct radiation and scattered radiation showed a single driving influence in spring, autumn and winter, in summer when vegetation living conditions were better, the factors appeared obvious inflection point, precipitation factor limit threshold changed with the season. In the interaction of factors, the interaction among human activities, precipitation, temperature, and vegetation types was the main driving force which affect NPP in the Qinghai-Tibet Plateau. Combining HAII and multiple natural factors, in the construction of vegetation ecological engineering on the Qinghai-Tibet Plateau, four factors (human activities, precipitation, temperature, and vegetation type) should be mainly considered, and the dominant factors were different in different seasons. In arid and rainless areas, human activities should be given priority. The study aims to provide a reference basis for regional ecosystem management in areas under different vegetation habitat conditions.