Data and code for: Functional traits mediate individualistic species-environment distributions at broad spatial scales while fine-scale species’ associations remain unpredictable

Ecological communities are structured by a diverse set of processes acting
at different spatial scales. In plant communities, assembly processes like
ecological sorting, limiting similarity, and stochastic events are all
expected to influence plant distributions and co-occurrence patterns. We
assembled a data set describing the distribution of 139 herbaceous plant
species within and among 257 forest stands in Wisconsin (USA) to elucidate
the spatial scales at which these assembly processes operate. Analyses of
these data in conjunction with detailed information about environmental
conditions, plant functional traits, and phylogenetic relationships
provided new insights into the scale-dependent drivers of plant community
assembly in temperate forest understories. Traits like leaf height,
specific leaf area, and seed mass all influenced individualistic plant
distributions along landscape-scale gradients in soil texture, soil
fertility, light availability, and climate while phylogenetic
relationships did not predict species-environment relationships. These
findings point to the importance of trait-mediated ecological sorting in
shaping individualistic plant distributions at broad spatial scales.
Contrary to our expectations about the importance of limiting similarity
at local scales, neither functionally similar nor phylogenetically related
herbs segregated among microsites within forest stands. We hypothesize
strong ecological sorting among forest stands coupled with stochastic
fine-scale interactions among species appear deterministic, niche-based
assembly processes at local scales.