Spatiotemporal characteristics and influencing factors of net primary production from 2000 to 2021 in China.

Abstract

With the rapid development of remote sensing, variously high temporal and spatial resolution products of different sensors were gradually applied aspects of researches, which could achieve rapid and low-cost monitors of terrestrial environment. It was meaningful to analyze the latest and long-term changes of net primary production (NPP), which could reflect the human-induced effects on ecological environment. In our study, we used Sen's slope and Mann-Kendall test to analyze the spatiotemporal changes of NPP. Then, we used fluctuation model and Moran model to reveal the stability and clusters of NPP, respectively. Next, we quantitatively analyzed NPP changes in the perspectives of land use types and provinces. Finally, we used geographically weighted regression (GWR) model to analyze effects of different factors on NPP. The result showed that NPP presented significant increase in most areas of China from 2000 to 2021. Especially, Loess Plateau showed obvious NPP increase. Meanwhile, "high-high" cluster of NPP difference were mainly distributed in the ecological policies-influenced areas. The slope in 5-15° has the highest growth trend, and the slope > 25° has the slowest growth trend. Cropland, forests, and shrub revealed an obvious improvement of NPP, which indicated afforestation and intensive farmed played a key role. Temperature, precipitation, population density, and elevation had significant effects on NPP (p < 0.05) in 2000, 2011, and 2021. The degree of effects of human activities was gradually increase in GWR model. In this scenario, related ecological policies had vita influencing on NPP improvement. Our study could provide a help for monitor of ecological environment and government policies.