Data from: Interaction between digestive strategy and niche specialization predicts speciation rates across herbivorous mammals

Biotic and abiotic factors often are treated as mutually exclusive drivers
of diversification processes. In this framework, ecological specialists
are expected to have higher speciation rates than generalists if abiotic
factors are the primary controls on species diversity but lower rates if
biotic interactions are more important. Speciation rate is therefore
predicted to positively correlate with ecological specialization in the
purely abiotic model but negatively correlate in the biotic model. In this
study, I show that the positive relationship between ecological
specialization and speciation expected from the purely abiotic model is
recovered only when a species-specific trait, digestive strategy, is
modeled in the terrestrial, herbivorous mammals (Mammalia). This result
suggests a more nuanced model in which the response of specialized
lineages to abiotic factors is dependent on a biological trait. I also
demonstrate that the effect of digestive strategy on the ecological
specialization–speciation rate relationship is not due to a difference in
either the degree of ecological specialization or the speciation rate
between foregut- and hindgut-fermenting mammals. Together, these findings
suggest that a biological trait, alongside historical abiotic events,
played an important role in shaping mammal speciation at long temporal and
large geographic scales.