Data from: Ant impacts on global patterns of bird elevational diversity

Using data on bird species elevational distributions from all of the
world’s mountain ranges, bird diets, and the distribution of the ant genus
Oecophylla, we show that global patterns in bird elevational diversity are
likely to be affected by competition with ants. Oecophylla is an abundant
and effective predator of invertebrates, preying on the same species that
invertivorous birds feed on. In mountain ranges with Oecophylla present in
the foothills, maximum species richness of invertivorous birds occurs, on
average, at 960m, ~450m higher than in mountain ranges without Oecophylla
to produce a mid-elevation peak in bird species richness. Where Oecophylla
is absent, bird species richness shows monotonic declines with increasing
elevation. Oecophylla likely reduces prey density for invertivorous birds,
low prey abundance reduces invertivorous bird density which in turn is
correlated with lower bird species richness. The findings emphasize that
competitive interactions between distantly related taxa can set range
limits.