Understanding resource use and dietary niche partitioning in a high-altitude predator guild using seasonal sampling and DNA metabarcoding

Understanding of predator feeding ecology, interactions among co-occurring predator species, and seasonal changes is critical for conservation management given the important role that predators play in shaping their ecosystems, but is lacking for most regions of the world. Dietary studies have demonstrated varying conclusions in the role that resource partitioning plays in the maintenance of predator communities due to complex inter-related factors that may shape prey use. We used DNA metabarcoding on 581 scat samples to determine the dietary composition, similarity, diversity, and niche overlap of eight predator species (Tibetan wolf (Canis lupus), snow leopard (Panthera uncia), Tibetan brown bear (Ursus arctos pruinosus), Eurasian lynx (Lynx lynx), Tibetan fox (Vulpes ferrilata), red fox (V. vulpes), Pallas's cat (Otocolobus manul), and beech marten (Martes foina)) across four sampling periods (September 2019, December 2019, March 2020, July 2020) in the Gouli Nature Reserve located in Dulan County, Qinghai Province, China. We identified 26 unique prey items, with blue sheep (Pseudois nayaur) and pika (Ochotona spp.) being most common. Small mammals had the highest frequency of occurrence, while domestic and wild ungulates contributed the most biomass. No significant differences in diet were detected across months, with the exception of March and December for the red fox (p = 0.010). Dietary niche overlap was greater than expected when considering all species (p < 0.001) across seasons and between the Tibetan wolf and snow leopard in March (p = 0.007) when compared for species pairs by season. This study contributes to understanding of fine-scale temporal changes in predator diet, and offers methodological and management strategies that may have applicability to other predator guilds living in complex landscapes.