期刊
FUNCTIONAL ECOLOGY
卷 33, 期 5, 页码 889-900出版社
WILEY
DOI: 10.1111/1365-2435.13300
关键词
alpine meadow; carbon fluxes; climate extremes; manipulative experiment; nonlinear response; precipitation gradient
类别
资金
- Ministry of Science and Technology of the People's Republic of China [2016YFC0501803]
- National Natural Science Foundation of China [31470528, 31625006]
Changes in precipitation have the potential to cause dramatic changes in ecosystem carbon (C) cycling; however, it remains unclear whether different components of the net ecosystem exchange (NEE) (e.g., C uptake vs. release, plant vs. microbe respiration, above-ground vs. below-ground plant respiration) have similar or differential sensitivity to precipitation gradients. We conducted a manipulative field experiment (from 2015 to 2017) 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 an alpine meadow to investigate the responses of the NEE components. Over the 3years, all C fluxes showed a nonlinear response to the precipitation gradients, except for root respiration. The most extreme drought treatment (1/12 P) caused strong reductions in NEE by 15.57%, gross primary productivity by 17.26% and ecosystem respiration by 19.05%, in contrast to the control. Plant respiration was more sensitive to precipitation change than microbe respiration, and above-ground plant respiration was more susceptible than below-ground respiration. Structural equation models revealed that the response of C fluxes under precipitation changes was primarily due to changes in the soil water content and above-ground net primary productivity. Our findings indicate that future precipitation changes, particularly extreme drought, will decrease ecosystem C fluxes with different magnitudes, leading to a consequent reduction of NEE. These emergent ecosystem properties are essential for the improved elucidation of carbon cycle dynamics and benchmarking models, to predict ecosystem responses to precipitation changes. A plain language summary is available for this article.
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