Multiple dimensions of dietary diversity in large mammalian herbivores

Theory predicts that trophic specialization (i.e., low dietary diversity) should make consumer populations sensitive to environmental disturbances, yet diagnosing specialists is complicated both by the difficulty of precisely quantifying diet composition and by definitional ambiguity—what makes a diet ‘diverse’?
We sought to characterize the relationship between taxonomic dietary diversity (TDD) and phylogenetic dietary diversity (PDD) in a species-rich community of large mammalian herbivores in semi-arid East African savanna. We hypothesized that TDD and PDD would be positively correlated within and among species, because taxonomically diverse diets are likely to include plants from many lineages.
By using DNA metabarcoding to analyze 1,281 fecal samples collected across multiple seasons, we compiled high-resolution diet profiles for 25 sympatric large-herbivore species. For each of these populations, we calculated TDD and PDD with reference to a DNA reference library for local ...