Human activities since the Industrial Revolution have triggered significant global changes. These global change factors(GCFs) are profoundly altering the N cycling, a crucial process for the productivity, structure, and functioning of terrestrial ecosystems. Understanding the interactions among GCFs is vital for accurately predicting future ecosystem dynamics and formulating effective conservation and management strategies.

Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences conducted a comprehensive meta-analysis to assess the main and interactive effects of four key GCFs, including elevated carbon dioxide(CO₂), increased nitrogen(N) deposition, climate warming, and precipitation shifts, on soil N pools and transformation rates across terrestrial ecosystems.

The findings demonstrate that individual GCF exerts varying influences on the soil N cycle. N addition and increased precipitation have the most significant positive effects on N pools and transformation rates, respectively. 

"Our analysis shows that the impact of N addition on the soil N cycle is generally amplified when combined with other GCFs,” explains DING Bangjing, the first author at the Wuhan Botanical Garden. 

While the majority of interactions among GCFs were found to be additive, the researchers also identified synergistic and antagonistic effects, underscoring the complexity of these interactions. 

"This study underscores the necessity of considering the integratve effects of multiple GCFs when assessing future ecosystem dynamics”, says Prof. LIU Wenzhi, the corresponding author.  "Integarting these interactions into Earth system models will significantly improve the accuracy of our predictions and allow for the development of more effective strategies to mitigate the impacts of global change on terrestrial ecosystems.”

Results have been published in Global Change Biology, titled “Additive Effects of Multiple Global Change Drivers on Terrestrial Nitrogen Cycling Worldwide”. This project was supported by the National Natural Science Foundation of China.

Interactive effects of given global change factor pairs on soil nitrogen cycling and the corresponding proportion of interaction types among individual observations (Image by WBG)