Abstract

Belowground bud banks mediate several critical processes in grassland ecosystems under global climate change. However, the functions of belowground bud bank along large-scale climatic gradients have rarely been reported. This study focused on the temperature and moisture transects at the regional scale to study the spatial pattern of belowground bud banks in grasslands of northern China, with purpose of examining: (1) whether the effects of temperature and moisture factors on belowground bud banks were similar; and (2) whether the effects of climate factors on bud density and diversity were similar. Results showed that bud banks had stronger linear relationships with factors in the zonal transect than those in the meridional transect; for bud densities, temperature-related factors along the zonal transect were major determinants, and the maximum annual snow depth (MAS) contributed the most to the total bud density, whereas bud bank diversity was significantly related to moisture factors along the meridional transect, but showed no significant relationships with any factors along the zonal transect. Our study demonstrated that temperature factors were better determinants of bud density, while moisture factors were better determinants of bud diversity at the regional scale. The MAS was the major factor in determining bud bank density, with a higher density in the colder region. These results are crucial for understanding the mechanisms underlying population regeneration and community dynamics under global climate change.