Spatiotemporal changes of Gross Primary Production in the Yellow River Basin of China under the influence of climate-driven and human-activity

Yellow River Basin of China is an important ecological reserve. However, the spatiotemporal patterns of Gross Primary Production (GPP) in the Yellow River Basin of China are unclear from interannual, seasonal and vegetation-type perspectives. The interactive effects of temperature, precipitation, leaf area index and evapotranspiration on GPP and the climate-driven and human -activity contributions to GPP remain unclear. This study uses solar-induced chlorophyll fluores-cence GPP data as indicator. Spatiotemporal characteristics of GPP are explored in the Yellow River Basin of China during 2001-2020 from interannual, seasonal and vegetation-type per-spectives. Geodetector and Terrestrial ecosystem model are introduced to dissect the driving mechanisms of GPP under the interaction of multiple factors and to clarify the contributions of climate-driven and human-activity to GPP. The results show a general upward trend of GPP in the Yellow River Basin of China during 2001-2020. However, GPP in local areas where climate change and human activity are intense show a rapid decline, especially in large and medium-sized cities with human settlements. The ranking of single factors driving GPP is leaf area index> precipitation> evapotranspiration> temperature, and the explanatory power for GPP spatial heterogeneity after multi-factor interaction shows nonlinear enhancement. The positive climate -driven effect on GPP is concentrated in the grassland of the Qinghai Tibet Plateau and Qilian Mountains in the west of the Yellow River Basin. The positive human-activity effect on GPP is mainly manifested through crops, concentrated in the southeastern farming region, showing significant seasonal variations. This study provides a theoretical basis for the ecological protec-tion and sustainable development of the Yellow River Basin in China.

Automated summary

This study explores the spatiotemporal patterns of Gross Primary Production (GPP) in the Yellow River Basin of China from interannual, seasonal, and vegetation-type perspectives using solar-induced chlorophyll fluorescence GPP data. The results show a general upward trend of GPP in the Yellow River Basin during 2001-2020, but intensive climate change and human activity lead to a rapid decline in local areas, especially in large and medium-sized cities. The driving factors of GPP rank as leaf area index>precipitation>evapotranspiration>temperature, and the explanatory power for GPP spatial heterogeneity is nonlinearly enhanced after multi-factor interaction. Climate-driven effects on GPP are concentrated in the grassland of the western region, while human-activity effects are mainly manifested through crops in the southeastern farming region with significant seasonal variations. This study provides a theoretical basis for the ecological protection and sustainable development of the Yellow River Basin in China.