Comparative analysis of long-term trends and climate sensitivity of spring phenology across forests, shrublands, and grasslands in the middle–high latitudes of the Northern Hemisphere

Climate change is profoundly reshaping terrestrial ecosystems, and the start of the growing season (SOS) serves as a key indicator for understanding ecosystem dynamics and climate-driven responses. However, the climate sensitivity of the SOS across vegetation types and its temporal evolution remain insufficiently understood. Here, we integrated multi-source remote sensing data, including the GIMMS-3G+ (Global Inventory Modeling and Mapping Studies, 3rd Generation V1.2) NDVI dataset from 1982 to 2022, to investigate the spatiotemporal dynamics and climate sensitivity of the SOS in forests, shrublands, and grasslands across the middle–high latitudes of the Northern Hemisphere. The SOS advanced significantly overall (−1.9 days per decade), with the strongest trend in shrublands (−2.94 days per decade), followed by forests (−1.68 days per decade), while grasslands remained largely stable (+0.02 days per decade). Shrublands showed the highest but declining temperature sensitivity, grasslands exhibited a moderate and increasing sensitivity, and forests maintained the lowest and most stable sensitivity. These results reveal distinct adaptive strategies among vegetation types under global warming and underscore the need to consider vegetation-specific and regional differences in ecological management to enhance ecosystem stability and carbon sequestration.