Tropical forest responses to increasing atmospheric CO2: current knowledge and opportunities for future research
Journal Publication ResearchOnline@JCUAbstract
Elevated atmospheric CO₂ concentrations (cₐ) will undoubtedly affect the metabolism of tropical forests worldwide; however, critical aspects of how tropical forests will respond remain largely unknown. Here, we review the current state of knowledge about physiological and ecological responses, with the aim of providing a framework that can help to guide future experimental research. Modelling studies have indicated that elevated cₐ can potentially stimulate photosynthesis more in the tropics than at higher latitudes, because suppression of photorespiration by elevated cₐ increases with temperature. However, canopy leaves in tropical forests could also potentially reach a high temperature threshold under elevated cₐ that will moderate the rise in photosynthesis. Below ground responses, including fine root production, nutrient foraging and soil organic matter processing, will be especially important to the integrated ecosystem response to elevated cₐ. Water use efficiency will increase as cₐ rises, potentially impacting upon soil moisture status and nutrient availability. Recruitment may be differentially altered for some functional groups, potentially decreasing ecosystem carbon storage. Whole-forest CO₂ enrichment experiments are urgently needed to test predictions of tropical forest functioning under elevated cₐ. Smaller scale experiments in the understorey and in gaps would also be informative, and could provide stepping stones towards stand-scale manipulations.
Journal
Functional Plant Biology
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Volume
40
ISBN/ISSN
1445-4416
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Issue
6
Pages Count
21
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Publisher
CSIRO Publishing
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EISSN
N/A
DOI
10.1071/FP12309