DOI: 10.5061/dryad.512p5
title: Data from: Trait-mediated community assembly: distinguishing the signatures of biotic and abiotic filters

description: Conflicting hypotheses predict how traits mediate species establishment
 and community assembly. Traits of newly establishing individuals are
 predicted to converge, or be more similar to the resident, preexisting
 community, when the biotic or abiotic environment favors a single best
 phenotype, but are predicted to diverge when trait differences reduce
 competitive interactions. We tested these competing hypotheses using
 transplant seedlings in an old-field environment, and assessed the
 contribution of inter- and intra-specific transplant trait variation to
 community-level patterns. Using a soil moisture gradient and resident
 plant removals, we determined when traits of newly-establishing plants
 converge or diverge from the resident community by calculating community
 weighted mean traits for transplant and resident communities. We saw
 evidence of environmentally- and competitively-driven trait shifts that
 resulted in both trait convergence and divergence from the resident
 community, whose traits reflect the combined effects of both drivers. Leaf
 dry matter content (LDMC) of transplants diverged in the presence of
 competition, whereas plant height and stem-specific density (SSD) showed
 the opposite pattern, converging with the resident community in their
 presence. Specific leaf area (SLA) shifted with competition but did not
 reflect resident community SLA. All transplant traits were influenced by
 soil moisture, often in an interaction with competition, indicating that
 the strength of convergence or divergence is contingent on the abiotic
 environment. Intraspecific differences in transplant traits among
 treatments were evident in three of four traits; intraspecific height and
 SLA trends mirrored transplant community-level trends, whereas
 intraspecific shifts in SSD were distinct from community-level trends. Our
 study shows competition between plant species may cause traits of newly
 establishing plants to converge with the resident community, as frequently
 as it selects for trait divergence. These opposing effects of competition
 suggest that it plays a pervasive role in both intraspecific and
 species-level trait differences among communities.
description: Functional trait
 dataFunctional trait data
 for transplants and individuals of the resident community within blocks.
 Blocks consisted of a “no competition plot”, a “competition plot”, and a
 control plot of the resident community and varied in their soil moisture.
 The traits measured include specific leaf area, leaf dry matter content,
 height, stem specific density, and plant biomass. All traits were measured
 at the end of the growing season. See the README file and description of
 Methods in the paper for metadata.16_01_2017_Traitdata.csvRelative abundance of established communityRelative abundance of species within the control, resident community plot. Values were used to weight the per-individual biomass in our calculations of community weighted means. See the README file for metadata.16_01_2017_relative_abundance_of_established_community.csv