Spatio-temporal differentiation of vegetation net primary productivity in Henan Province as well as its driving factors

The net primary productivity (NPP) of vegetation, exhibiting regional differentiation, serves as a crucial parameter for determining the carbon source/sink of ecosystems. Based on the MOD17A3HGF, topography, and human activity data, this study delved into the spatio-temporal differentiation of vegetation NPP in Henan Province from 2010 to 2020 and its response to driving factors using methods like the gravity center model, trend analysis, and the geographical detector model. Moreover, it revealed the explanatory power and interactions of the driving factors. The results are as follows: ① Temporally, the vegetation NPP from 2010 to 2020 displayed a slightly fluctuating upward trend, averaging 424.89 gC·m^-2·a^-1. Its gravity center exhibited significant temporal differentiation, with the average center of gravity closer to the geometric center. ② Spatially, the vegetation NPP values increased from the northeast to the southwest and were dominated by median values (300~600 gC·m^-2·a^-1). ③ In terms of influencing factors, the vegetation NPP showed a higher correlation with precipitation compared to temperature. Moreover, it first increased and then decreased with an increase in altitude and slope. The areas with altitudes below 200 m and slopes less than 2° contributed the most to NPP in the study area. The vegetation NPP on sunny slopes was higher than that on shady slopes. In the case of land use changes, the shift to arable land plays a significant role in the increase of total NPP. ④ The geographical detection results indicate that precipitation exhibited the highest explanatory power for changes in vegetation NPP. The two-factor interactions all showed an enhanced relationship, with the q value of precipitation ∩ longitude being the highest. These findings provide data support for ecological protection and high-quality development of Henan Province.