Being led by Sichuan University, a team of researchers from Sun Yat-sen University; Zhejiang A & F University; Université du Québec à Chicoutimi, Canada; Florida State University, Tallahassee, FL, USA, published in Nature Climate Change a research paper entitled “Leaf Senescence Exhibits Stronger Climatic Responses During Warm than During Cold Autumns” on July 6. The paper reveals the response mechanism of autumn phenology change-- leaf senescence in time of global warming. SCU's Lei Chen is the first author and one of the corresponding authors. Zhiyong Liu of Sun Yat-sen University and Jianquan Liu of Sichuan University are co corresponding authors, and Sichuan University is the first work unit.
The growth and development of trees, such as germination, leaf expansion, flowering, leaf discoloration, will show periodic laws with the cycle of climate change in the four seasons of the year. These are called phenological phenomena. Climate change caused by global temperature rise greatly affects tree phenology, leading to the advance of spring phenology (germination, leaf expansion, flowering).
“A warmer world could extend the growing seasons for plants. Changes in spring phenology have been studied, yet autumn phenology remains poorly understood. Using >500,000 phenological records of four temperate tree species between 1951 and 2013 in Europe, we show that leaf senescence in warm autumns exhibits stronger climate responses, with a higher phenological plasticity, than in cold autumns, indicating a nonlinear response to climate. The onset of leaf senescence in warm autumns was delayed due to the stronger climate response, primarily caused by night-time warming. However, daytime warming, especially during warm autumns, imposes a drought stress which advances leaf senescence. This may counteract the extension of growing season under global warming. These findings provide guidance for more reliable predictions of plant phenology and biosphere–atmosphere feedbacks in the context of global warming.” (Abstract)
Climatic responses of leaf senescence of four temperate tree species in Europe during 1951–2013.
These findings help people better understand the complexity of plant phenology changes in autumn in the context of global climate change, and help develop new vegetation models to predict the impact of climate change on forest ecosystems in the future.
In addition, Nature Climate Change published in the same issue a research paper entitled "Light Limitation Regulates the Response of Autumn Terrestrial Carbon Uptake to Warming" by Yao Zhang et al. of Columbia University, which reported the effect of light on photosynthetic carbon assimilation in the context of global warming.
It is worth mentioning that Nature Climate Change also published a review article entitled “Autumn Greening in a Warming Climate", which gave a detailed interpretation and comments on the above two studies. These two independent studies have shown that warming climate can change the autumn phenology, and the temperature rise delays leaf senescence in autumn, which means that the dormancy period of vegetation is shortened. A shortened dormancy period may weaken the adaptability of vegetation to environmental change, which has a significant impact on ecology. For example, vegetation will be more vulnerable to extreme climate (drought, high temperature, frost, etc.).
Article links：https://www.nature.com/articles/s41558-020-0820-2
https://www.nature.com/articles/s41558-020-0806-0
Link to the review article: https://doi.org/10.1038/s41558-020-0852-7
