Projects per year
Abstract / Description of output
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.
Keywords / Materials (for Non-textual outputs)
- tropical forest
- climate change
- moisture deficit
- leaf dark respiration
- night-time foliar carbon emissions
- specific leaf area
- leaf area index
- through-fall exclusion experiment
- SOIL CO2 EFFLUX
- TROPICAL FOREST
- DARK RESPIRATION
- PLANT RESPIRATION
- EASTERN AMAZONIA
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- 4 Finished
6/12/02 → 5/12/03
Grace, J., Malhi, Y. & Meir, P.
1/07/00 → 30/06/02