In this post, Qianxin Jiang, a Ph.D. student from Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, discusses and shares her published paper in Journal of Plant Ecology, “Species asynchrony maintains community stability under different warming conditions.”

Why study the effects of warming in different seasons?

Global warming is an established fact, but an often-overlooked detail is that not all seasons are warming at the same rate. In cold and ecologically fragile regions like the Tibetan Plateau, winters are warming much faster than summers, a phenomenon known as "asymmetric seasonal warming", which is becoming increasingly common. Most past warming experiments simulated consistent, year-round warming, which doesn't fully reflect the true natural process. We know that the low temperatures and snow cover of winter are key factors shaping the alpine grassland ecosystem. So, what happens when the coldest season is no longer so cold? Will ecosystem stability—its ability to maintain function in the face of environmental fluctuations—be enhanced or weakened? To solve this puzzle, we established an 8-year field manipulative experiment in the heart of the Tibetan Plateau to directly compare the different effects of "winter warming" versus "year-round warming" on the community stability of alpine grasslands.

What are the findings of this study?

Our study found that at the macroscopic community level, the alpine grassland demonstrated surprising resilience. Neither winter warming nor year-round warming significantly altered the species richness or stability of the entire community. This stability was primarily maintained by "species asynchrony"—that is, different species respond to environmental changes at different times or intensities, and their compensatory, fluctuating dynamics collectively maintain the stability of the total community biomass.

However, the story becomes more complex when we look deeper inside the community. We found that winter warming significantly enhanced the stability of dominant species (the most abundant species in the community). The mechanism behind this is that winter warming promoted the growth of grasses while suppressing the growth of forbs. This compensatory dynamic of "one rises, one falls" stabilized the total biomass of the dominant species group. Year-round warming, in contrast, significantly reduced the stability of common species (those with intermediate abundance). This is likely because the sustained pressure of warming and drought disrupted the internal compensatory balance among common species, leading to greater fluctuations in their biomass.

This study shows that even if the overall stability of an ecosystem appears unchanged, the fate of different abundance groups within it may have already undergone profound shifts.

Some views on ecological research

This study reminds us that when investigating the impacts of global change on ecosystems, we cannot be satisfied with macroscopic, averaged conclusions. Nature's changes are often subtle and complex, and the real story may be hidden at different ecological levels—the community might seem stable, but the dynamics of dominant and common species could already be drastically different. The charm of ecology lies in going into the field, using long-term observation and elaborate experimental designs to uncover these patterns hidden beneath the surface. For the Tibetan Plateau, the dominant grass species are the main food source for the livestock that local pastoralists depend on. Therefore, understanding how winter warming stabilizes these key species through inter-species interactions is not just an interesting scientific question; it also has significant practical implications for the region's sustainable development.

About the author

Qianxin Jiang

I am a Ph.D. candidate at the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, under the supervision of Prof. Juntao Zhu. My primary research focuses on the responses of grassland ecosystem structure and function to global change. For three consecutive years, I conducted growing-season observations and plant community surveys at the Naqu National Observation and Research Station for Alpine Grassland Ecosystems in Tibet. I also participated in multiple scientific expeditions and sampling campaigns at other sites, including Bange and Nam ucuo. My current research investigates how community assembly processes contribute to the structural and functional changes in grassland ecosystems under extreme precipitation events.

If you are interested in more details about the story, please read our paper “Qianxin Jiang, Juntao Zhu*, Peili shi, Yunlong He, Yangjian Zhang, Jun Yan, Wendong Xie, Ning Zong*, Ge Hou, Ruonan Shen and Jiahe Zheng. Species asynchrony maintains community stability under different warming conditions” published in Journal of Plant Ecology (https://doi.org/10.1093/jpe/rtae037).