Trait-based plant ecology: some history and some future

Since around the year 2000, trait-based ecology has become self-aware as a strand of research within ecology. How did this happen? What is trait-based ecology now? And where might it go in future? This paper offers selective answers to those questions. We first outline the history leading up to the emergence of trait-based plant ecology during the 1990s. Second, we assess briefly what has been achieved up to mid-2020s. Third, we discuss two challenges (among many) for trait-based plant ecology over the next 25 yr. One is about the boundaries of species ranges along temperature gradients. Some of these boundaries may be decided by thermal tolerance, others by biotic interactions such as competition or pathogens. How can we identify which applies to which species? Which traits, feasible to measure across many species, might help with this? A second major challenge is about the global zonation of vegetation physiognomy or biome types. How well can we explain this in terms of traits, and from first principles, meaning via eco-evolutionary models for why different trait values should be competent and competitive in different settings? First-principle rules for how ecosystems are constructed should be central to ecology as a discipline.