Understanding the impact of plant competition on the coupling between vegetation and the atmosphere

Abstract

Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation functioning and associated atmospheric interactions. Our aim was to investigate how the coupling between vegetation and atmosphere is influenced by plant competition. Though included in some coupled vegetation-atmosphere models, little attention has been paid to systematically study the impact of plant competition in determining the evolution of surface and atmospheric variables. We used a coupled vegetation-atmosphere model and included a new representation of plant competition. We compared the model results with diurnal data from Ameriflux Bondville site over a growing season. Including competition improved LAI (Leaf Area Index) and net ecosystem exchange of CO 2 (NEE) predictions; if competition was not considered, there were strong deviations from observations. Remarkably, competition increased LAI while it reduced whole stand photosynthesis, resulting in a less negative NEE. Finally, independent of competition, latent heat flux, surface temperature, specific humidity, and atmospheric CO 2 are well reproduced by the model. Only the sensible heat flux was overestimated, mainly due to the imbalance in the surface energy balance that can lead to lower measured sensible heat fluxes. Sensitivity analysis showed that the importance of plant competition on model outcomes increases with more nitrogen and water availability and may differ between soil types. We thus quantified the potential effect of plant competition in a coupled vegetation-atmosphere system and showed that it strongly influences this system, and therefore, we propose that competition should be considered in more vegetation-atmosphere models.

Tragedies and Crops: Understanding Natural Selection To Improve Cropping Systems

“…For instance, using this approach it was shown that EGT models realistically predicted elevated CO 2 effects on crop structure and functioning (including atmospheric feedback) as found in field-applied elevated CO 2 experiments [52,53].…”

Impact of Future Warming and Enhanced [CO2] on the Vegetation‐Cloud Interaction

“…Examples are uncertainties related to the development in canopy structure (e.g., increase in leaf area index; Anten et al, 2004) or leaf thickness and nitrogen allocation (Bezemer et al, 1998). Furthermore, when genotypic responses of plants to climate change are considered, the vegetation distribution might be affected through natural selection (Van Loon et al, 2015). As most plant species respond differently to atmospheric perturbations, regional or even continental changes in the surface energy balance might occur that have a strong effect on the land-atmosphere interactions.…”

Plant–plant interactions mediate the plastic and genotypic response ofPlantago asiaticato CO2: an experiment with plant populations from naturally high CO2areas

“…For example, game theoretical models predicted that selection might favour plants with more leaf area or that grow taller than would be needed for maximized production (Anten, 2002;Falster and Westoby, 2003). In addition, a game theoretical model, which assumed that the best competitors will prevail under elevated [CO 2 ], gave better predictions of measured LAI and photosynthesis and net ecosystem productivity in elevated [CO 2 ] experiments than models that assume that plants with the inherent highest photosynthesis will prevail (Van Loon et al, 2014, 2015. Together with the findings reported here, this also suggests that competition strongly mediates plant adaptations to elevated [CO 2 ] and this may have important consequences for future species distribution and vegetation functioning.…”

“…For instance, a study that included competition through natural selection (i.e. game theoretical principles) accurately predicted the LAI, net photosynthesis and stomatal conductance of soybean stands grown at elevated [CO 2 ] obtained in free air carbon dioxide enrichment (FACE) experiments, and this prediction was much better than a model that did not consider these interactions (Van Loon et al, 2014, 2015. However, the role of plant-plant interactions in mediating vegetation responses to elevated [CO 2 ] is still poorly understood (Bazzaz and McConnaughay, 1992;Song et al, 2009).…”