Abstract: Plant phenology is a sensitive indicator of ecosystem responses to global change, yet how phenological responses vary among developmental stages, environmental contexts, and plant functional strategies remains poorly resolved in grasslands. We conducted a meta-analysis of 1,004 observations extracted from 67 publications to quantify the effects of warming, precipitation change, and nitrogen (N) addition on five phenological stages: green-up date (GUD), flowering date (FLD), fruiting date (FRD), reproductive onset date (RD), and senescence date (SD). Warming was associated with significant shifts across several stages, advancing GUD (-2.657 ± 0.004 d), FLD (-3.314 ± 0.002 d), and FRD (-1.871 ± 0.002 d), while delaying SD (1.300 ± 0.002 d). RD showed no significant overall response to warming. The magnitude of warming-related GUD advancement varied with mean annual temperature (slope = -0.02201), mean annual precipitation (slope = -0.00024), and experimental duration (slope = -0.03301). Increased precipitation advanced GUD (-2.039 ± 0.016 d) and FLD (-1.370 ± 0.005 d), whereas decreased precipitation and N addition produced limited overall shifts but stronger context dependence. Phenological responses also differed among life-history and bud-position groups: significant early-season relationships were more frequently detected in perennials and geophytes, whereas annuals and chamaephytes showed more stage-specific reproductive or late-season relationships. Reproductive responses varied more strongly along climatic gradients than early-season responses. Together, these findings show that grassland phenological responses are stage-, context-, and strategy-dependent and support incorporating developmental stage and plant strategy into future phenological predictions.

Key words: global change, grassland phenology, life history, bud position, environmental gradients, meta-analysis