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

摘要: It seems intuitive that species diversity promotes functional diversity. For example, more plant imply diverse leaf chemistry and thus kinds of food for herbivores. Here we argue the evolution trait variance challenges this view. We show trait-based eco-evolutionary processes force to evolve narrower breadths in tightly packed communities, their effort avoid competition with neighboring species. This effect is so strong as reduce overall space coverage, overhauling expected positive relationship between species- Empirical data from Galapagos land snail communities proved consistent claim. As a consequence, species-poor may misjudge species-rich ones, vice versa.