Impacts of experimentally imposed drought on leaf respiration and morphology in an Amazon rain forest

Research output: Contribution to journalArticle


P>1. The Amazon region may experience increasing moisture limitation over this century. Leaf dark respiration (R) is a key component of the Amazon rain forest carbon (C) cycle, but relatively little is known about its sensitivity to drought. 2. Here, we present measurements of R standardized to 25 degrees C and leaf morphology from different canopy heights over 5 years at a rain forest subject to a large-scale through-fall reduction (TFR) experiment, and nearby, unmodified Control forest, at the Caxiuana reserve in the eastern Amazon. 3. In all five post-treatment measurement campaigns, mean R at 25 degrees C was elevated in the TFR forest compared to the Control forest experiencing normal rainfall. After 5 years of the TFR treatment, R per unit leaf area and mass had increased by 65% and 42%, respectively, relative to pre-treatment means. In contrast, leaf area index (L) in the TFR forest was consistently lower than the Control, falling by 23% compared to the pre-treatment mean, largely because of a decline in specific leaf area (S). 4. The consistent and significant effects of the TFR treatment on R, L and S suggest that severe drought events in the Amazon, of the kind that may occur more frequently in future, could cause a substantial increase in canopy carbon dioxide emissions from this ecosystem to the atmosphere.


  • Dan Metcalfe
  • Raquel Lobo-do-Vale
  • Manuela M. Chaves
  • Joao P. Maroco
  • Luiz E. O. C. Aragao
  • Yadvinder Malhi
  • Antonio L. Da Costa
  • Alan P. Braga
  • Paulo L. Goncalves
  • Joao De Athaydes
  • Mauricio Da Costa
  • Samuel S. Almeida
  • Catherine Campbell
  • Vaughan Hurry
  • Mathew Williams
  • Patrick Meir
External organisations
  • University of Oxford
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Geography


  • tropical forest, climate change, moisture deficit, leaf dark, respiration, night-time foliar carbon emissions, specific leaf area, leaf area index, through-fall exclusion experiment
Original languageEnglish
Pages (from-to)524-533
JournalFunctional Ecology
Issue number3
Publication statusPublished - 2010
Publication categoryResearch
Externally publishedYes