Shifts in plant respiration and carbon use efficiency at a large-scale drought experiment in the eastern Amazon

D. B. Metcalfe, P. Meir, L. E. O. C. Aragao, R. Lobo-do-Vale, D. Galbraith, R. A. Fisher, M. M. Chaves, J. P. Maroco, A. C. L. da Costa, S. S. de Almeida, A. P. Braga, P. H. L. Goncalves, J. de Athaydes, M. da Costa, T. T. B. Portela, A. A. R. de Oliveira, Y. Malhi, M. Williams

Research output: Contribution to journalArticlepeer-review

Abstract

P>The effects of drought on the Amazon rainforest are potentially large but remain poorly understood. Here, carbon (C) cycling after 5 yr of a large-scale through-fall exclusion (TFE) experiment excluding about 50% of incident rainfall from an eastern Amazon rainforest was compared with a nearby control plot.

Principal C stocks and fluxes were intensively measured in 2005. Additional minor components were either quantified in later site measurements or derived from the available literature.

Total ecosystem respiration (R-eco) and total plant C expenditure (PCE, the sum of net primary productivity (NPP) and autotrophic respiration (R-auto)), were elevated on the TFE plot relative to the control. The increase in PCE and R-eco was mainly caused by a rise in R-auto from foliage and roots. Heterotrophic respiration did not differ substantially between plots. NPP was 2.4 +/- 1.4 t C ha-1 yr-1 lower on the TFE than the control. Ecosystem carbon use efficiency, the proportion of PCE invested in NPP, was lower in the TFE plot (0.24 +/- 0.04) than in the control (0.32 +/- 0.04).

Drought caused by the TFE treatment appeared to drive fundamental shifts in ecosystem C cycling with potentially important consequences for long-term forest C storage.

Original languageEnglish
Pages (from-to)608-621
Number of pages14
JournalNew Phytologist
Volume187
Issue number3
DOIs
Publication statusPublished - 2010

Keywords

  • Amazon rain forest
  • carbon cycling
  • carbon dioxide
  • carbon use efficiency
  • drought
  • gross primary productivity
  • net primary productivity
  • partitioning
  • ABOVEGROUND LIVE BIOMASS
  • NET PRIMARY PRODUCTION
  • MOIST TROPICAL FOREST
  • BELOW-GROUND CARBON
  • RAIN-FOREST
  • CLIMATE VARIABILITY
  • SOIL EMISSIONS
  • NITROUS-OXIDE
  • GAS-EXCHANGE
  • NITRIC-OXIDE

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