Response of net primary productivity to precipitation exclusion in a savanna ecosystem

FOREST ECOLOGY AND MANAGEMENT

卷:429

Article

Jin, Yanqiang^1,5  Li, Jing^1,5  Liu, Chenggang²  Liu, Yuntong¹  Zhang, Yiping¹  Song, Qinghai¹  Sha, Liqing¹  Chen, Aiguo³  Yang, Daxin³  Li, Peiguang⁴ 

[1] Chinese Acad Sci, CAS Key Lab Trop Forest Ecol, Xishuangbanna Trop Bot Garden, Menglun 666303, Peoples R China

[2] Chinese Acad Sci, CAS Key Lab Trop Plant Resources & Sustainable Us, Xishuangbanna Trop Bot Garden, Menglun 666303, Peoples R China

[3] Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Yuanjiang Savanna Ecosyst Res Stn, Yuanjiang 653300, Peoples R China

[4] Chinese Acad Sci, Yantai Inst Coastal Zone Res, Yellow River Delta Ecol Res Stn Coastal Wetland, Yantai 264003, Peoples R China

[5] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

关键词: Carbon accumulation;    Drought;    Litterfall;    Plant functional types;    Savanna;   

DOI  :  10.1016/j.foreco.2018.07.007

来源: Elsevier

【 摘 要 】

Declines in precipitation are expected to affect plant performance and ecosystem carbon uptake. The response of ecosystem productivity to declines in precipitation and potential underlying mechanisms have been well studied in many biomes; however, little is known about the role of declines in precipitation and the involved mechanisms in savanna ecosystems. In a 4-year field precipitation manipulation experiment, we simulated four levels of precipitation exclusion (control, 30%, 50% and 70%) to assess the effects of declines in precipitation on net primary productivity (NPP) in a savanna ecosystem in southwestern China. NPP was strongly correlated with soil water content during the experimental period. Precipitation exclusion significantly decreased the NPP of the entire vegetation including trees, shrubs, perennials and litterfall but significantly increased the NPP of annuals. Our results suggested that precipitation exclusion can reduce the productivity of savannas and that plant functional types differ in sensitivity to precipitation exclusion. These findings imply that future declines in precipitation in savanna regions may negatively impact carbon accumulation and may induce shifts in plant functional types to buffer the effects of declines in precipitation on productivity and stabilize ecosystem function in savannas.

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