Unchanged carbon balance driven by equivalent responses of production and respiration to climate change in a mixed‐grass prairie
- Co‐Innovation Center for Sustainable Forestry in Southern China College of Biology and the Environment Nanjing Forestry University Nanjing Jiangsu Province 210037 China, Department of Microbiology &, Plant Biology University of Oklahoma 101 David L. Boren Blvd. Norman OK 73019 USA
- Department of Microbiology &, Plant Biology University of Oklahoma 101 David L. Boren Blvd. Norman OK 73019 USA
- Department of Geography University of California Santa Barbara CA 93106 USA
- Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China
- Key Laboratory of Forestry Intelligent Monitoring and Information Technology Research of Zhejiang Province Zhejiang A&,F University Lin'an Zhejiang 311300 China
Responses of grassland carbon (C) cycling to climate change and land use remain a major uncertainty in model prediction of future climate. To explore the impacts of global change on ecosystem C fluxes and the consequent changes in C storage, we have conducted a field experiment with warming (+3 °C), altered precipitation (doubled and halved), and annual clipping at the end of growing seasons in a mixed‐grass prairie in Oklahoma, USA , from 2009 to 2013. Results showed that although ecosystem respiration ( ER ) and gross primary production ( GPP ) negatively responded to warming, net ecosystem exchange of CO 2 ( NEE ) did not significantly change under warming. Doubled precipitation stimulated and halved precipitation suppressed ER and GPP equivalently, with the net outcome being unchanged in NEE . These results indicate that warming and altered precipitation do not necessarily have profound impacts on ecosystem C storage. In addition, we found that clipping enhanced NEE due to a stronger positive response of GPP compared to ER , indicating that clipping could potentially be an effective land practice that could increase C storage. No significant interactions between warming, altered precipitation, and clipping were observed. Meanwhile, we found that belowground net primary production ( BNPP ) in general was sensitive to climate change and land use though no significant changes were found in NPP across treatments. Moreover, negative correlations of the ER / GPP ratio with soil temperature and moisture did not differ across treatments, highlighting the roles of abiotic factors in mediating ecosystem C fluxes in this grassland. Importantly, our results suggest that belowground C cycling (e.g., BNPP ) could respond to climate change with no alterations in ecosystem C storage in the same period.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0004601
- OSTI ID:
- 1401408
- Journal Information:
- Global Change Biology, Journal Name: Global Change Biology Journal Issue: 5 Vol. 22; ISSN 1354-1013
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English