A trait-based ecosystem model suggests that long-term responsiveness to rising atmospheric CO2 concentration is greater in slow-growing than fast-growing plants

作者：Ali Ashehad A; Medlyn Belinda E^*; Crous Kristine Y; Reich Peter B

来源：Functional Ecology, 2013, 27(4): 1011-1022.

DOI：10.1111/1365-2435.12102

• carbon dioxide
• nitrogen uptake
• relative growth rate
• species traits

1. Atmospheric carbon dioxide concentration (C-a) has a direct and measurable effect on plant growth. However, it does not affect all plant species equally, which could lead to shifts in competitive dominance of species in ecosystems. %26lt;br%26gt;2. We used a dynamic plant carbon-nitrogen model to systematically examine how species traits affect the long-term C-a responsiveness of C-3 plants when growing as established mono-cultures in the field. The model was tested against responses of 7 C-3 herbaceous species growing in a free-air C-a enrichment (FACE) experiment (BioCON) in Minnesota, USA. %26lt;br%26gt;3. Model simulations showed that several species traits affected the C-a response strongly, giving rise to a number of testable hypotheses about interspecific differences in responsiveness to C-a. The largest responses to rising C-a were obtained for species with low carbon-use efficiency (net primary production: gross primary production ratio), low foliar carbon allocation, low stomatal conductance, low instantaneous photosynthetic nitrogen use efficiency and low specific leaf area. %26lt;br%26gt;4. In general, our model predicted that, for established plants growing in resource-limited field conditions, species with slow growth rates would be most responsive to elevated C-a. This prediction was supported by data from the BioCON experiment. %26lt;br%26gt;5. Our model also predicts that, for young plants growing in non-resource-limited conditions, species with high growth rates will be most responsive to elevated C-a. This difference in species ranking under different resource availabilities is largely explained by the indirect effects of C-a on leaf area. Leaf-area feedbacks favour fast-growing species the most during leaf-area expansion, but following stand maturation they favour slow-growing species the most. %26lt;br%26gt;6. These results imply that species that respond strongly to elevated C-a in short-term (nonresource-limited) glasshouse experiments are unlikely to also be the most responsive in resource-limited field conditions, and therefore that we cannot directly extrapolate from glasshouse experiments to predict which species will be most responsive to elevated C-a in the long term.

• 出版日期2013-8