In our latest Insight, Dr Fangyue Zhang (Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences,) talks about her new paper, Differential responses of ecosystem carbon flux components to experimental precipitation gradient in an alpine meadow, why this work is important and what got her in to ecology.

---

About the research

What’s your paper about?

This paper is about how ecosystem carbon processes respond to altered precipitation regimes, especially extreme precipitation events, which will become more severe and frequent in the coming decades with global climate change.

More specifically, it’s about how different components of the net ecosystem exchange (e.g., carbon uptake vs. release, plant vs. microbe respiration, aboveground vs. belowground plant respiration) change under extreme precipitation events, and if they have similar or different sensitivity to precipitation gradients.

 

What’s the background behind your paper?

In our paper, we conducted a precipitation gradient experiment with six levels to examine the responses of net ecosystem exchange (NEE) and its components to precipitation changes in an alpine meadow.

 

Precipitation amount has been proven to determine NEE in grassland. According to prediction models, the relationship between precipitation levels and NEE should not be linear. Recognizing these nonlinear responses is essential for reducing uncertainties toward the prediction of ecosystem carbon cycling in response to climate change, particularly under extreme conditions. But until now, few experimental precipitation studies have been conducted to simulate precipitation gradient changes or imposed extreme levels of precipitation to explore the nonlinear responses of NEE and its components.

Considering how carbon allocation varies toward aboveground versus belowground under precipitation changes, aboveground plant respiration and root respiration may have a different response to precipitation gradient as well. To date, ecologists have known little about the different responses of C flux components to precipitation changes, compared with the net primary productivity responses.

 

Who should read your paper (and why)?

Everybody, of course! This paper raises questions that could be interesting for ecologists interested in ecosystem carbon cycling response to climate change. Precipitation regimes are changing, particularly extreme precipitation events, which will become more severe and frequent in the coming decades on a global scale.

Our paper also contains information that could help environmental managers improve predictions of the global carbon cycle in the context of climate change.

 

Did you have any problems setting up the experiment?

Sure! Our experiment was carried out in an alpine meadow with the elevation of 3500 m. Altitude sickness and the tough environment make the experiment setup and field measurements very challenging. It took more than two weeks to mechanically inserted fiberglass sheets into the ground to a depth of 40 cm around each plot, in order to cut off the lateral movement of soil water.

 

How is your paper new or different from other work in this area?

One of the most innovative aspects of our work was the experimental design, with six precipitation treatments, including 1/12 annual precipitation (P), 1/4 P, 1/2 P, 3/4 P, P, and 5/4 P in the alpine meadow. We imposed extreme levels of precipitation by using combinations of water catchments and rainout shelters for the whole year round. We also compared the different sensitivity of components of net ecosystem exchange (such as plant respiration, microbe respiration, aboveground respiration and root respiration), which has received far less attention before.

 

 

Now that this paper has been published, what’s the next step in this field?

This article focused on alpine meadow in the Tibetan Plateau because it is particularly vulnerable to climate changes. But we do not know yet if the response pattern that we found in our study also applies to other ecosystem types. More field experiments with extremity gradients should be designed, with combinations of extreme duration in different ecosystem types. These experiments can help to advance our understanding of how extreme climate sensitivity varies across a broad range of terrestrial ecosystems. Rather than traditional site-based experiments, coordinated distributed drought networks can help to improve our understanding at regional and global scales.

 

About The Author

 

How did you get involved in ecology?

 

Ever since I was a child, I have been fascinated by the natural world. I prefer working outdoors to staying in the office. I chose ecology as my major when I was a postgraduate student. At that time my research was focused on short-term effects of CO₂ elevation and nitrogen deposition on carbon cycling in a mid-subtropical forest. The field experiment and the surprising findings ignited my passion for ecology. And I continued to study ecology during my PhD.

What is the best thing about being an ecologist?

The field work and keeping in contact with nature.

What is the worst thing about being an ecologist?

As an ecologist, the worst thing is seeing someone misunderstand or misuse the concept of “ecology”.

What would you like to do next?

Continue the field measurement and learn new statistical methods for data analyses.