Species pools and differential performance generate variation in leaf nutrients between native and exotic species in succession

<ol> <li class="line" id="line-5"> A central aim of invasion biology has been to identify key functional differences between native and exotic species to determine which traits may be responsible for invasion success and impacts. There are two primary ways that differences may exist between native and exotic species&mdash;the traits of the local species pools may differ, or the way that the traits interact with their environment may differ. </li> <li class="line" id="line-7"> We explored leaf nutrient concentrations as functional traits that directly link to plant metabolic processes by sampling healthy, mature leaves from 119 native and exotic taxa across a wide range of successional statuses in New Jersey, USA. Leaf nutrient concentration data (carbon, calcium, magnesium, nitrogen, phosphorus, potassium) were paired with long&hyphen;term community dynamics from the Buell&ndash;Small Succession Study to evaluate abundance&hyphen;weighted trait values over succession for native and exotic species. </li> <li class="line" id="line-9"> After accounting for differences across growth forms, there were minimal differences in foliar nutrients based on plant origin, with only lower leaf carbon and higher leaf potassium in exotic species. However, these differences were not sufficient to generate overall differences between native and exotic species in a multivariate analysis. In contrast, the successional trajectories of the abundance&hyphen;weighted trait values for most leaf nutrients differed strongly between native and exotic plants. While this pattern may be partially attributable to variation in the species pool for carbon and potassium, successional processes generated differential sorting, suggesting underlying differences in how the same traits function in native and exotic assemblages. </li> <li class="line" id="line-11"> <i> Synthesis </i> . These results suggest that both variation in the species pool and variation in the successional selection of plant traits can generate functional differences between native and exotic plants. Assessments of trait differences between native and exotic species will require information on traits and plant performance to unambiguously link traits to function in dynamic plant communities. </li></ol>