Chinese scientists explore alpine ecosystem carbon cycling responses to climate change

XINING -- Chinese scientists have proposed new insights into how alpine ecosystem carbon cycling may respond to long-term climate change via a long-term study of plant phenological events in alpine grasslands, according to the Northwest Institute of Plateau Biology (NWIPB) of the Chinese Academy of Sciences.

This joint study explored the roles of plant phenology in the response of plant productivity to decadal climate warming and cooling over a period lasting 15 years, the NWIPB said.

Jointly conducted by researchers at the NWIPB and multiple universities and institutions across China, the study has been published in the Journal of Ecology.

Climate change is expected to intensify over the coming decades. It is potentially leading substantial impacts on above-ground net primary productivity (ANPP), a key indicator of ecosystem functioning and carbon sequestration, according to Zhang Zhenhua, a researcher at the NWIPB.

Previous studies have shown that warming significantly alters carbon cycling processes, such as photosynthesis, respiration and decomposition, which can jointly regulate ANPP.

Focusing on the alpine ecosystem and global climate change, the joint research team conducted the study aimed at tracing the long-term effects of climate change, particularly those associated with the cooling phases, which remain largely understudied due to the challenges of experimental implementation.

The study was based on a 15-year continuous observation at an experimental platform at the national field scientific observation and research station of the alpine grassland ecosystem in Haibei Tibetan Autonomous Prefecture, northwest China's Qinghai Province.

Researchers systematically monitored the dynamics of ANPP and analyzed its response mechanisms, combined with high-frequency plant phenology and community productivity formation dynamics.

The study results indicated that, after 15 years, ANPP of this alpine ecosystem had increased under warming but decreased under cooling. However, only the warming effect intensified over time, whereas the cooling effect showed no detectable temporal trend.

It is worth noting that both warming and cooling effects on ANPP were integrated by early-season phenology. The promoting effect of warming on ANPP gradually intensified over time, while the inhibitory effect of cooling did not show significant time dependence, Zhang said.

"The key finding of this study is that phenological changes in the early growing season play a significant role in regulating the response of ANPP to temperature changes," Zhang added.

Findings of the study demonstrated that changes in plant phenological events mediate the impacts of decadal climate warming and cooling on ANPP in alpine grasslands.

"This study enhances our understanding of how temperature variations influence plant functional traits and thereby regulate ecosystem functions. In subsequent research, we will examine the effects of changes in plant diversity and functional traits on ecosystem stability across various climate scenarios," Zhang said.