Warming advanced leaf senescence in alpine plants through advancing leaf emergence and increasing soil drought

Plant autumn phenology, including leaf senescence, plays an important role in regulating growing season length, productivity and ecosystem carbon cycling. However, there is still uncertainty about the mechanisms driving the timing and duration of leaf senescence under climate warming and precipitation change. Here, we used 1800 phenological records (the onset, end and duration of leaf senescence) of 10 common species monitored during a 3‐year experiment on climate warming and precipitation manipulation in alpine meadows on the eastern Tibetan Plateau to research how plant autumn phenology responds to climate change and the underlying mechanisms. We found that warming overrides precipitation manipulation in advancing the onset and end of leaf senescence, but the duration of leaf senescence was almost unchanged. Increased soil temperature, soil drought and advanced leaf emergence due to warming regulate the autumn phenology response to warming. Specifically, warming advanced the onset of leaf senescence at the community and different functional group levels by advancing leaf emergence. While warming also advancing the end of leaf senescence at the community level and forbs by advancing leaf emergence and increasing soil drought. Synthesis . Our results suggest that leaf senescence in alpine herbaceous plants will occur earlier than currently expected under a warming climate, implying that the warming‐induced delay in autumn senescence in alpine ecosystems may be overestimated or even reversed. Moreover, this finding emphasizes the important roles of spring phenology and soil drought in regulating autumn phenology in response to climate warming.