Spatiotemporal Dynamics of Vegetation Net Primary Productivity on the Zoige Plateau from 2000 to 2019 and Its Relationship with Climate Factors

Based on annual MODIS–NPP data and monthly temperature and precipitation data from 2000 to 2019, the temporal and spatial variation characteristics of vegetation NPP and its relationship with climate factors in Zoige Plateau were analyzed by means of univariate linear regression and partial correlation analysis. The results showed that the average annual NPP of vegetation in Zoige Plateau was 366.55 gC/(m²·a), with a trend of higher in the east and lower in the west; the average vegetation NPP increased at a rate of 1.66 gC/(m²·a) from 2000 to 2019, and the area of vegetation NPP increased was 95.75% of the whole plateau. The average annual NPP of vegetation was different among different ecosystem types, forest ecosystem > wetland ecosystem > grassland ecosystem; the interannual growth rate is also different, wetland ecosystem > grassland ecosystem > forest ecosystem. There was a weak negative correlation between vegetation NPP and precipitation in the Zoige Plateau, indicating that precipitation was not the dominant climate factor affecting NPP in the Zoige Plateau; the variation of vegetation NPP in Zoige Plateau was mainly affected by temperature, which was the main driving factor of NPP variation in Zoige Plateau. In addition, it was found that maximum temperature and minimum temperature had different effects on vegetation NPP in Zoige Plateau, and the effect of maximum temperature on vegetation NPP in Zoige Plateau was more significant.