[Spatiotemporal Evolution Characteristics and Driving Mechanisms of Vegetation NEP in Northeast China Based on MODIS-NPP].

As a crucial ecological security barrier and carbon sink functional zone in China， the spatiotemporal evolution of vegetation net ecosystem productivity （NEP） in Northeast China holds significant implications for achieving the "dual-carbon" goals. In this study， NEP was calculated using MODIS-NPP data and meteorological data from 2001 to 2023. Combined with the Theil-Sen slope， Mann-Kendall test， and Hurst index， the spatiotemporal dynamics and future trends of NEP were revealed. Additionally， its driving mechanisms were analyzed using a ridge regression model and optimal parameter Geodetector. The results showed that： ① During the study period， the average NEP reached 234.19 g·m-2， with a significant increase at a rate of 3.43 g·（m2·a）-1 （P<0.05）， peaking at 286.60 g·m-2 in 2022. ② Spatially， NEP presented a pattern of "high in the surrounding areas and low in the central region，" with forested areas such as the Greater Khingan Range and Changbai Mountains being high-value regions. ③ In the future， NEP will continue to increase in 79.31% of the study area （H=0.52）. ④ Population density had the largest relative contribution rate to the temporal variation of NEP （27.68%）， followed by precipitation （24.65%）. The positive and negative contributions of all factors were concentrated in the range of -0.01 to 0.015 g·（m2·a）-1. Land use， population density， and precipitation mainly showed positive effects， while the absolute contributions of average temperature and maximum temperature were negative. ⑤ Multi-factor coupling analysis indicated that land use type had the highest explanatory power for the spatial differentiation of vegetation NEP， while the two-factor interaction between precipitation and maximum temperature had the highest explanatory power for the spatial heterogeneity of NEP， highlighting the synergistic influence of natural conditions and human activities. This study provides a scientific basis for regional carbon sink management and ecological restoration and is of great significance for local resource development and utilization as well as carbon trading.