How light competition between plants affects their response to climate change
2014
Loon, Marloes P. | Schieving, Feike | Rietkerk, Max | Dekker, Stefan C. | Sterck, Frank | Anten, Niels P. R.
How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO₂ concentration, and modeled the extent to which local plant–plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO₂ and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO₂ increase. When CO₂ elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO₂ on leaf area index (LAI) well within the range of observed effects obtained by Free air CO₂ enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change.
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