Predrought and Its Persistence Determined the Phenological Changes of Stipa krylovii in Inner Mongolia

Clarifying the response of plant phenology to drought duration is helpful for accurately interpreting and predicting carbon sinks in ecosystems. Based on different phenological periods dominant species Stipa krylovii monthly, seasonal, semiannual time scale typical steppe Inner Mongolia from 1983 2018, results revealed that (1) start growing season (SOS) was characterized by an advance–delay–advance pattern, heading stage (HOS), flowering (FOS), end (EOS) all showed consistent advanced trends, which provided additional insight into conclusions previous studies found SOS arid semiarid regions. (2) The mechanism timing not consistent. Among mechanism, delayed because January–February at scales but April scales. HOS/FOS June–July scales, EOS August–September (3) More importantly, SOS, HOS, FOS, were affected predrought its persistence, effects greater closer occurred. (4) At monthly scale, droughts January, June, August critical affecting HOS/FOS, EOS, while seasonal February, June–July, September EOS. this study enrich our understanding how affects periods, providing a basis improving models.