Community-level root trait, environmental data and R codes.xlsx

To explore how community-level root quantity and quality traits vary across environmental gradients, we focus on two representative grassland regions in northern China: the Inner Mongolian Plateau (IMP, temperate grassland) and the Tibetan Plateau (TP, alpine grassland). During the peak growing season (July–September) in 2018, we selected 10 sampling sites free from human disturbances (such as grazing and mowing) along east–west transects within each region: the IMP (112.15°–123.51°E, 43.55°–45.11° N, elevation ~140–1,300 m) and the TP (80.15°–95.45°E, 31.38°–32.48° N, elevation > 4000 m), resulting in 20 sites in total (Fig. S1 and Table S1). The distance between two adjacent sites was approximately 100 km. These sites encompassed diverse climatic conditions, soil properties, and vegetation types. Using root cores, we quantified community-level root quantity traits (mass, length, area, nitrogen per land area) and quality traits (length, area, nitrogen per root mass and tissue density) across 20 grasslands on the Inner Mongolian Plateau (IMP) and the Tibetan Plateau (TP) in China. Specifically, root quantity traits include total root mass (RMA), root length (RLA), root area (RAA), and root nitrogen content per unit land area (RNA). Root quality or efficiency traits include the community-level values of mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD), root nitrogen concentration (RN). Climatic and soil variables (0–30 cm depth) were used to determine the environmental effects on variation in community-level root traits.