Data from: The ecological importance of intraspecific variation

Human activity is causing wild populations to experience rapid trait
change and local extirpation. The resulting effects on intraspecific
variation could have substantial consequences for ecological processes and
ecosystem services. Although researchers have long acknowledged that
variation among species influences the surrounding environment, only
recently has evidence accumulated for the ecological importance of
variation within species. We conducted a meta-analysis comparing the
ecological effects of variation within a species (intraspecific effects)
with the effects of replacement or removal of that species (species
effects). We evaluated direct and indirect ecological responses, including
changes in abundance (or biomass), rates of ecological processes and
changes in community composition. Our results show that intraspecific
effects are often comparable to, and sometimes stronger than, species
effects. Species effects tend to be larger for direct ecological responses
(for example, through consumption), whereas intraspecific effects and
species effects tend to be similar for indirect responses (for example,
through trophic cascades). Intraspecific effects are especially strong
when indirect interactions alter community composition. Our results
summarize data from the first generation of studies examining the relative
ecological effects of intraspecific variation. Our conclusions can help
inform the design of future experiments and the formulation of strategies
to quantify and conserve biodiversity.