Data from: Energetic constraints on species coexistence in birds

The association between species richness and ecosystem energy availability
is one of the major geographic trends in biodiversity. It is often
explained in terms of energetic constraints, such that coexistence among
competing species is limited in low productivity environments. However, it
has proven challenging to reject alternative views, including the null
hypothesis that species richness has simply had more time to accumulate in
productive regions, and thus the role of energetic constraints in limiting
coexistence remains largely unknown. We use the phylogenetic relationships
and geographic ranges of sister species (pairs of lineages who are each
other’s closest extant relatives) to examine the association between
energy availability and coexistence across an entire vertebrate class
(Aves). We show that the incidence of coexistence among sister species
increases with overall species richness and is elevated in more productive
ecosystems, even when accounting for differences in the evolutionary time
available for coexistence to occur. Our results indicate that energy
availability promotes species coexistence in closely related lineages,
providing a key step toward a more mechanistic understanding of the
productivity–richness relationship underlying global gradients in
biodiversity.