Trait-dependent diversification in angiosperms: Patterns, models and data

Variation in species richness across the tree of life, accompanied by the
incredible variety of ecological and morphological characteristics found
in nature, has inspired many studies to link traits with species
diversification. Angiosperms are a highly diverse group that has
fundamentally shaped life on earth since the Cretaceous and illustrate how
species diversification affects ecosystem functioning. Numerous traits and
processes have been linked to differences in species richness within this
group, but we know little about their relative importance and how they
interact. Here, we synthesized data from 152 studies that used
state-dependent speciation and extinction (SSE) models on angiosperm
clades. Intrinsic traits related to reproduction and morphology were often
linked to diversification but a set of universal drivers did not emerge as
traits did not have consistent effects across clades. Importantly, SSE
model results were correlated to dataset properties – trees that were
larger, older, or less well-sampled tended to yield trait-dependent
outcomes. We compared these properties to recommendations for SSE model
use and provide a set of best practices to follow when designing studies
and reporting results. Finally, we argue that SSE model inferences should
be considered in a larger context incorporating species' ecology,
demography and genetics.