Data and code from: Similar trait-based successional assembly in native and introduced plants despite species pool differences

What drives the composition of invaded communities and the local abundance
of introduced species are key questions in ecology. Community-assembly
theory provides a useful framework for addressing these questions.
Specifically, the environmental filtering model of community assembly
predicts that a species’ presence and abundance in a community depends on
the interaction between its functional traits and the local environmental
filters. However, for introduced species, larger-scale dispersal and
introduction-related filters may restrict their regional trait pool. Here
we tested  this framework using long-term data from 50+ years of
old-field vegetation succession. We asked whether native and introduced
plant assemblages followed the same trait-based assembly rules. We also
asked whether local functional dissimilarities between the two can be
explained by regional species pool differences, a possibility that has
rarely been addressed. We found strong similarities in the assembly
processes of native and introduced plants. Average height and seed mass of
both groups increased over time, consistent with previous studies of
old-field succession. Moreover, the two showed similar trait-abundance
relationships. While there were also some differences, particularly in
their trait-incidence relationships, these differences appeared to be
minor.Further, we identified species pool constraints on introduced
species, and found that the exotic species pool was biased towards early
successional traits. Lastly, we found that highly invasive exotic species
were also likely to deviate from the expected trait-abundance
relationship, suggesting a link between the two. These results suggest
that introduced species generally follow the same assembly rules as native
species. They also indicate that species pool differences can result in
local functional composition differences, even when the two groups follow
the same assembly rules. Moreover, there may be a link between species
invasiveness and deviation from assembly rules, which, if further
confirmed, provides a potential method of identifying strong invaders.