Response of ecosystem carbon exchange to warming and nitrogen addition during two hydrologically contrasting growing seasons in a temperate steppe
Response of ecosystem carbon exchange to warming and nitrogen addition during two hydrologically contrasting growing seasons in a temperate steppe
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温带草原两个水文对比生长季节生态系统碳交换对变暖和氮添加的响应
DOI：
10.1111/j.1365-2486.2008.01807.x
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发表时间：
2009-06
影响因子：
11.6
通讯作者：
Shuli Niu
中科院分区：
文献类型：
--
作者：
Jianyang Xia;Shiqiang Wan;Shuli Niu
在全球未来气候模式预测中，一个仍然存在的很大的不确定性来源是生态系统碳（C）循环对气候变化的反馈。我们在一个温带草原进行了增温和施氮的野外操控实验。
A large remaining source of uncertainty in global model predictions of future climate is how ecosystem carbon (C) cycle feedbacks to climate change. We conducted a field manipulative experiment of warming and nitrogen (N) addition in a temperate steppe in northern China during two contrasting hydrological growing seasons in 2006 [wet with total precipitation 11.2% above the long‐term mean (348 mm)] and 2007 (dry with total precipitation 46.7% below the long‐term mean). Irrespective of strong intra‐ and interannual variations in ecosystem C fluxes, responses of ecosystem C fluxes to warming and N addition did not change between the two growing seasons, suggesting independence of warming and N responses of net ecosystem C exchange (NEE) upon hydrological variations in the temperate steppe. Warming had no effect on NEE or its two components, gross ecosystem productivity (GEP) and ecosystem respiration (ER), whereas N addition stimulated GEP but did not affect ER, leading to positive responses of NEE. Similar responses of NEE between the two growing seasons were due to changes in both biotic and abiotic factors and their impacts on ER and GEP. In the wet growing season, NEE was positively correlated with soil moisture and forb biomass. Negative effects of warming‐induced water depletion could be ameliorated by higher forb biomass in the warmed plots. N addition increased forb biomass but did not affect soil moisture, leading to positive effect on NEE. In the dry growing season, NEE showed positive dependence on grass biomass but negative dependence on forb biomass. No changes in NEE in response to warming could result from water limitation on both GEP and ER as well as little responses of either grass or forb biomass. N addition stimulated grass biomass but reduced forb biomass, leading to the increase in NEE. Our findings highlight the importance of changes in abiotic (soil moisture, N availability) and biotic (growth of different plant functional types) in mediating the responses of NEE to climatic warming and N enrichment in the semiarid temperate steppe in northern China.
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影响因子：
6.1
作者：
E. Zavaleta;M. Shaw;N. Chiariello;Brian D. Thomas;E. Cleland;C. Field;H. Mooney
通讯作者：
E. Zavaleta;M. Shaw;N. Chiariello;Brian D. Thomas;E. Cleland;C. Field;H. Mooney
影响因子：
5.5
作者：
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影响因子：
3.7
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影响因子：
11.6
作者：
J. Welker;J. Fahnestock;G. Henry;Kevin W. O'Dea;R. Chimner
通讯作者：
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影响因子：
10.1
作者：
Keesing, F
通讯作者：
Keesing, F