Warming Effects on Ecosystem Carbon Fluxes Are Modulated by Plant Functional Types

Ji Chen, Yiqi Luo, Jianyang Xia, Kevin R. Wilcox, Junji Cao, Xuhui Zhou, Lifen Jiang, Shuli Niu, Katerina Y. Estera, Rujin Huang, Feng Wu, Tafeng Hu, Junyi Liang, Zheng Shi, Jianfen Guo, Rui Wu Wang

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

Despite the importance of future carbon (C) pools for policy and land management decisions under various climate change scenarios, predictions of these pools under altered climate vary considerably. Chronic warming will likely impact both ecosystem C fluxes and the abundance and distribution of plant functional types (PFTs) within systems, potentially interacting to create novel patterns of C exchange. Here, we report results from a 3-year warming experiment using open top chambers (OTC) on the Tibetan Plateau meadow grassland. Warming significantly increased C uptake through gross primary productivity (GPP) but not ecosystem respiration (ER), resulting in a 31.0% reduction in net ecosystem exchange (NEE) in warmed plots. The OTC-induced changes in ecosystem C fluxes were not fully explained by the corresponding changes in soil temperature and moisture. Warming treatments significantly increased the biomass of graminoids and legumes by 12.9 and 27.6%. These functional shifts were correlated with enhanced local GPP, but not ER, resulting in more negative NEE in plots with larger increases in graminoid and legume biomass. This may be due to a link between greater legume abundance and higher levels of total inorganic nitrogen, which can potentially drive higher GPP, but not higher ER. Overall, our results indicate that C-climate feedbacks might be closely mediated by climate-induced changes in PFTs. This highlights the need to consider the impacts of changes in PFTs when predicting future responses of C pools under altered climate scenarios.

Original languageEnglish (US)
Pages (from-to)515-526
Number of pages12
JournalEcosystems
Volume20
Issue number3
DOIs
StatePublished - Apr 1 2017
Externally publishedYes

Keywords

  • Tibetan plateau
  • aboveground biomass
  • climate change
  • ecosystem carbon fluxes
  • experimental warming
  • net ecosystem exchange
  • plant functional types
  • soil inorganic nitrogen

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Environmental Chemistry

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