Hu Zhi, Wang Huanjiong, Dai Junhu, Ge Quansheng, Lin Shaozhi
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2022 May 18;13:830573. doi: 10.3389/fpls.2022.830573. eCollection 2022.
Spring warming could induce earlier leaf-out or flowering of temperate plant species, and decreased chilling in winter has a delaying effect on spring phenology. However, the relative contribution of the decreased chilling and increased forcing on spring phenological change is unclear. Here, we analyzed the experimental data for 14 temperate woody species in Beijing, China and quantified the forcing requirements (FR) of spring phenology and chilling sensitivity (the ratio of the FR at the low chilling condition to the FR at the high chilling condition) for each species. Furthermore, using species-specific functions between the amount of chilling and FR, we established a phenological model to simulate the annual onset dates of spring events during the past 69 years (1952-2020) and in the future (2021-2099) under RCP 4.5 and RCP 8.5 climate scenarios. We also developed a novel method to quantitatively split the predicted phenological change into the effects caused by changes in forcing and those caused by changes in chilling. The results show that the FR of spring events decreased with the increase in the amount of chilling, and this relationship could be described as an exponential decay function. The basic FR (the FR at the high chilling condition) and chilling sensitivity varied greatly among species. In the 1952-2020 period, the advancing effect of increased forcing was stronger than the effect of chilling, leading to earlier spring events with a mean trend of -1.96 days/decade. In future climate scenarios, the spring phenology of temperate species would continue to advance but will be limited by the decreased chilling. The species with lower chilling sensitivities showed stronger trends than those with high chilling sensitivities. Our results suggested that the delaying effect of declining chilling could only slow down the spring phenological advance to a certain extent in the future.
春季变暖可能会促使温带植物物种提前展叶或开花，而冬季寒冷程度的降低对春季物候有延迟作用。然而，寒冷程度降低和促成因素增加对春季物候变化的相对贡献尚不清楚。在此，我们分析了中国北京14种温带木本植物的实验数据，并量化了每种植物春季物候的促成需求（FR）和寒冷敏感性（低寒冷条件下的FR与高寒冷条件下的FR之比）。此外，利用寒冷量与FR之间的物种特异性函数，我们建立了一个物候模型，以模拟过去69年（1952 - 2020年）以及未来（2021 - 2099年）在RCP 4.5和RCP 8.5气候情景下春季事件的年度开始日期。我们还开发了一种新方法，将预测的物候变化定量分解为由促成因素变化引起的影响和由寒冷变化引起的影响。结果表明，春季事件的FR随着寒冷量的增加而降低，这种关系可以用指数衰减函数来描述。基本FR（高寒冷条件下的FR）和寒冷敏感性在物种间差异很大。在1952 - 2020年期间，促成因素增加的推进作用强于寒冷的作用，导致春季事件提前，平均趋势为-1.96天/十年。在未来气候情景中，温带物种的春季物候将继续提前，但会受到寒冷程度降低的限制。寒冷敏感性较低的物种比寒冷敏感性高的物种表现出更强的趋势。我们的结果表明，寒冷程度下降的延迟作用在未来只能在一定程度上减缓春季物候的提前。
