Gyuri Barabas (University of Linköping, Sweden)

Title: The evolution of trait variance creates a tension between species and functional diversity

Abstract: It seems intuitively obvious that species diversity begets functional (trait) diversity: the more plant species there are, the more varied their leaf chemistry will be; more species of crops provide more kinds of food; etc. In this talk I argue that the evolution of trait variance challenges this view. In a trait-based eco-evolutionary model, I show that when species richness is low, individual species evolve large trait variation, while in species-rich communities species avoid competition by evolving narrow trait breadths. This effect can be so strong that those communities with more but narrower species will cover a smaller fraction of the available trait space than those with fewer but intraspecifically more variable ones. The expected positive relationship between species and functional diversity is thus overhauled, a result which proved extremely robust to changes in model setup and parameterization. I finish by presenting and discussing empirical data consistent with this claim.