Our knowledge of the relationship between vegetation rain use efficiency (RUE) and precipitation is critical for predicting potential responses of grassland ecosystems to changing precipitation regimes. However, a generalized pattern of RUE along the precipitation gradient is still unavailable. Here we examined RUE variations in both Tibetan and global grasslands across precipitation gradients, using actual measurements obtained from a regional survey and a global dataset. RUE in Tibetan grasslands exhibited a unimodal pattern across the precipitation gradient, with an increasing trend in dry alpine steppe and a decreasing trend in mesic alpine meadow. RUE in alpine steppe was lower than in alpine meadow, largely due to their differences in species richness, soil texture and soil carbon content. The RUE of Tibetan grasslands was lower than global grasslands but displayed a similar trend with precipitation, suggesting the generality of a unimodal RUE pattern across diverse grassland types across broad precipitation gradients.
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