Generalist carnivores can be effective biodiversity samplers of terrestrial vertebrates

Biodiversity conservation relies on effective practical methods for assessing species occurrences and distributions, particularly for elusive species. Generalist carnivores are widely distributed and relatively abundant predators with broad dietary ranges, and as such could potentially serve as "biodiversity samplers" of sympatric prey communities. To test this hypothesis, we analyzed leopard cat (Prionailurus bengalensis) and red fox (Vulpes vulpes) diets to survey local vertebrate communities in several mountainous areas in China. Fecal DNA metabarcoding analysis revealed that leopard cat prey from five mountain ranges across China included 99 vertebrate taxa representing 12 taxonomic orders and red fox prey from two of those mountain ranges displayed a similar degree of diversity, which was highly correlated with local species records accrued by traditional survey methods. Our results show that diet metabarcoding analysis of generalist carnivores can be an effective, noninvasive, and economically viable tool for biodiversity monitoring to inform management decisions. In addition, we explored selection criteria and potential candidate species for carnivore sampler-based biodiversity studies in other parts of the world.