Data from: Phenotypic selection in natural populations: what limits directional selection?

Studies of phenotypic selection document directional selection in many
natural populations. What factors reduce total directional selection, and
the cumulative evolutionary responses to selection? We combine two
datasets for phenotypic selection, representing more than 4600 distinct
estimates of selection from 143 studies, to evaluate the potential roles
of fitness trade-offs, indirect (correlated) selection, temporally varying
selection, and stabilizing selection for reducing net directional
selection and cumulative responses to selection. We detected little
evidence that trade-offs among different fitness components reduced total
directional selection in most study systems. Comparisons of selection
gradients and selection differentials suggest that correlated selection
frequently reduced total selection on size, but not on other types of
traits. The direction of selection on a trait often changes over time in
many temporally-replicated studies, but these fluctuations have limited
impact in reducing cumulative directional selection in most study systems.
Analyses of quadratic selection gradients indicated stabilizing selection
on body size in at least some studies, but provided little evidence that
stabilizing selection is more common than disruptive selection for most
traits or study systems. Our analyses provide little evidence that fitness
trade-offs, correlated selection or stabilizing selection strongly
constrain the directional selection reported for most quantitative traits.