If traits responsible for resource use or host susceptibility to natural
enemies are not widely conserved, or if the sum of plant–soil
interactions remain neutral, relatedness may in fact be a poor
predictor of negative plant–soil feedback effects.
More than two decades of plant–soil feedback research have
generated sufficient number of studies to allow us to test the utility
of evolutionary history for predicting negative plant–soil feedback
effects. Here we present a formal meta-analysis of 329 experiments
which compared the growth response of plant species to soil
cultured by conspecifics relative to heterospecifics (133 plant
species in 276 unique pairwise interactions). For each pairwise
species interaction, we calculated Hedges’ d standardized mean
difference, where a negative effect size corresponds to a positive
plant response to heterospecific-cultured soil relative to conspecific-
cultured soil (i.e. a signal of negative plant–soil feedbacks).We
then extracted the phylogenetic distances between species pairs in
each experiment from a chronogram built using publicly available
data. We meta-regressed our calculated effect sizes on the
phylogenetic distance estimates by fitting a hierarchical Bayes
linear model that accounts for sampling dependence (e.g. same
conspecific control soils across multiple experiments), and hierarchical
dependencies (e.g. multiple experiments within the same
study) in the dataset (Stevens & Taylor, 2008). We estimated an