Infodoc : Sciences, Techniques et Culture

Functional diversity is a key driver of ecological performances within ecosystems. However, the determinants of functional diversity at the species level are still poorly studied. To tackle this question, we studied the relative contributions of genetic background and environmental conditions to the emergence of wood, leaf and architecture traits in eleven tree species of Colombian dry forests. We show that different populations in these species present remarkable genetic differences, that they inhabit locations of clearly distinguishable soil and climate conditions, and that individuals of distinct populations occupy separate locations of the trait space. Fitting linear mixed models involving the effects of both climate and genetics show that genetic models consistently out perform e[...]

Functional diversity is a key driver of ecological performances within ecosystems. However, the determinants of functional diversity at the species level are still poorly studied. To tackle this question, we studied the relative contributions of genetic background and environmental conditions to the emergence of wood, leaf and architecture traits in eleven tree species of Colombian dry forests. We show that different populations in these species present remarkable genetic differences, that they inhabit locations of clearly distinguishable soil and climate conditions, and that individuals of distinct populations occupy separate locations of the trait space. Fitting linear mixed models involving the effects of both climate and genetics show that genetic models consistently out perform environmental models for all theme asured response traits, and that models including interaction terms between environmental and genetic parameters present an even higher explanatory power than genetic models for wood traits and specific leaf area. Automatic selection of the variables using Aikiko Information Criterium (AIC) of the different variables shows that genetic variables are mostly involved in the explanation of wood and architecture traits across the different species, that genetic and environmental variables are equally involved in the explanation of specific leaf area, and that our explanatory variables have limited explanatory power over the dry matter contents of the leaves. Finally, we show that the standardized size of genetic and genetic/environment interaction terms is considerably larger than the effect size of soil and climate terms across all the measured traits and for a majority of species. Altogether, our results show that genetic background is the main determinant of the assessed functional traits within the species of interest, and that the involvement of environmental parameters looks to be mediated by their interaction with genetic terms. These result indicate that genetic variability is themain determinant of functional diversity at the species level.