[Spatio-temporal Dynamics of Vegetation Net Primary Productivity and Its Response to Climate Change and Human...

Amid rapid global changes， understanding how vegetation productivity responds to climate change and human activities has attracted considerable scientific interest. However， research focusing on arid and ecologically fragile regions remains limited. Advancing studies in this area is important for a deeper understanding of carbon source-sink dynamics in arid ecosystems. Xinjiang， as one of China's typical arid and ecologically fragile regions， is also an area with significant changes in vegetation productivity. Using long-term （2001-2022） MODIS net primary productivity （NPP） data， this study applied Theil-Sen Median trend estimation， Mann-Kendall test， stability analysis， and residual analysis to assess vegetation NPP trends in Xinjiang and their responses to climate change and human activity. The validity of the residual method was further evaluated via partial correlation analysis. The results showed that from 2001 to 2022， vegetation NPP in Xinjiang （expressed in C） exhibited a significant increasing trend at a rate of 0.84 g·（m²·a）^-1 （P<0.05）. Approximately 33.4% of the vegetated area exhibited significant increases， primarily located around oases in the Tarim Basin， as well as the Tianshan and Altai Mountains. The primary drivers of increased NPP in Xinjiang were either human activities alone or their combined effects with climate change. The impact of climate change on NPP growth was relatively minor， contributing less than 20% in areas covering 52.34% of the vegetated region. In contrast， in 72.6% of vegetated regions in Xinjiang， human activities contributed more than 60% to the NPP increase. Partial correlation results indicated that the residual method was effective in isolating the influence of anthropogenic activities. The findings highlight the significant role of human activities in enhancing vegetation productivity in Xinjiang and comparable arid ecosystems.