Abstract: Despite much recent progress, our understanding of plant phenology response to climate change remains incomplete. In particular, how and to what extent climate warming affects the vegetative and reproductive phenology of different plant functional groups in northern grassland ecosystems remains largely unexplored. Here, we compiled data of 1758 observations from 25 individual studies and carried out a meta-analysis of plant phenology in relation to temperature changes across a range of plant species and functional groups in northern China. We show that climate warming tended to extend the duration of reproductive phenology while having no effect on the duration of vegetative phenology. We also identified specific temperature sensitivities for different phenological stages: 1.73 days °C⁻¹ for budding, −3.38 days °C⁻¹ for leaf spreading and 0.56 days °C⁻¹ for yellow withered stage, respectively. Notably, warming resulted in earlier leaf spreading in shrubs and semi-shrubs, but caused a delay in the budding time of sedges. In terms of reproductive phenology, temperature sensitivity was −1.73 days °C⁻¹ for flowering time, −2.53 days °C⁻¹ for fruit ripening and −0.11 days °C⁻¹ for fruit shedding, respectively. Warming advanced the flowering and fruit repining time of all functional groups except for legumes. Our results indicate that elevated temperatures advanced reproductive phenology and extended its duration in northern grasslands, while showing no impact on vegetative phenology. Our findings demonstrate the differential responses of different functional groups to warming, highlighting the diverse growth strategies and adaptation of grassland plants in a warming world.

Key words: Climate change, grassland, reproductive phenology, vegetative phenology, plant functional groups