Data from: A case for the “Competitive exclusion – tolerance rule” as a general cause of species turnover along environmental gradients

Closely-related, ecologically-similar species often segregate their
distributions along environmental gradients of time, space, and resources,
but previous research suggests diverse underlying causes. Here, we review
reciprocal removal studies in nature that experimentally test the role of
interactions among species in determining their turnover along
environmental gradients. We find consistent evidence for asymmetric
exclusion coupled with differences in environmental tolerance causing the
segregation of species pairs, where a dominant species excludes a
subordinate from benign regions of the gradient, but is unable to tolerate
challenging regions to which the subordinate species is adapted.
Subordinate species were consistently smaller and performed better in
regions of the gradient typically occupied by the dominant species
compared to their native distribution. These results extend previous ideas
contrasting competitive ability with adaptation to abiotic stress to
include a broader diversity of species interactions (intraguild predation,
reproductive interference) and environmental gradients, including
gradients of biotic challenge. Collectively, these findings suggest that
adaptation to environmental challenge compromises performance in
antagonistic interactions with ecologically-similar species. The
consistency of this pattern across diverse organisms, environments, and
biomes suggests generalizable processes structuring the segregation of
ecologically-similar species along disparate environmental gradients, a
phenomenon that we propose should be named the Competitive exclusion –
tolerance rule.