Spatiotemporal dynamics and driving factors of net primary productivity in Asian terrestrial ecosystems

Net Primary Productivity (NPP) serves as a critical indicator for assessing terrestrial ecosystem quality and characterizing carbon sequestration capacity. Utilizing a long-term NPP remote sensing inversion dataset, this study systematically uncovers the spatiotemporal evolution patterns of vegetation NPP in Asia through historical trend analysis, identification of mutation nodes, ecological stability assessment, multi-scale periodic feature analysis, and sustainability forecasting. The combined driving effects of topographical constraints, climate variability, and human activities are quantitatively examined using structural equation modeling (SEM), elucidating the multifactorial synergistic impact on vegetation productivity. The main findings are: (1) Temporally, Asian vegetation NPP exhibits a fluctuating upward trend with a principal cycle of approximately 20 years, marked by two distinct rise-decline transitions during the study period. (2) Spatially, a clear southeast-high/northwest-low differentiation pattern is observed, with significant NPP increases in East Asian monsoon regions and South Asian agricultural zones, contrasted by declines in tropical rainforests (notably in the Malay Archipelago) and eastern Mongolian grasslands. (3) Persistence analysis indicates that 53 % of vegetated areas exhibit random NPP variability, 4 % maintain stable conditions, and only 2 % (mainly in South and East Asian croplands) show sustained growth potential. A trend reversal from negative to positive is noted in 27 % of the regions (e.g., Malay Archipelago and eastern Mongolia), while 12 % of cropland-dominant areas may face growth stagnation or decline. (4) Driver quantification demonstrates climate factors exert the strongest explanatory power (total effect: 0.38), while topography generates complex influences through direct negative (-0.14) and indirect positive (0.04) effects. Human activities (total effect: 0.06) are primarily driven by synergistic GDP-population growth. These findings provide a scientific foundation for evaluating Asian ecosystem services and guiding regional carbon cycle management under global change scenarios.