Reintroduced large herbivores significantly influence ecosystem structure, species diversity, and functioning, necessitating careful monitoring. The population of Asiatic wild asses (Near Threatened by IUCN) in the Negev Desert, Israel, has been steadily increasing, raising concerns about habitat degradation due to overgrazing and trampling. While diet reflects these interactions, limited data exist on the seasonal, spatial, and sex-specific dietary patterns of this population.

In this pilot study, we assessed dietary patterns using field surveys and DNA metabarcoding. We collected 252 fresh wild ass samples (158 males and 52 females identified by molecular assays) in spring and summer across the species’ range in the Negev Highlands.

Metagenomic analysis revealed no significant differences in alpha diversity based on sex, season, or location (p > 0.05, PERMANOVA). However, beta diversity analysis indicated distinct dietary compositions related to sex and season (p < 0.05, PERMANOVA). In summer, the diet included annual plants like Erodium, Schismus, and Avena, along with perennials such as Helianthemum, Noea, and Atriplex. The spring diet primarily comprised annuals. Generalized Linear Mixed Models (GLMM) showed that beta diversity of genera was influenced by sex, season, and physical distance, with closer samples exhibiting similar compositions regardless of season or sex (p < 0.05, Wald Chi-square test). Summer samples displayed higher beta diversity, likely due to the compulsive consumption of resources, whereas spring allowed for more selective feeding as a result of availability of abundant preferable vegetation, in line with optimal foraging theory. Interestingly, males exhibited greater dietary diversity than females across both seasons. This may reflect social dynamics, as males maintain territories near water sources, granting access to varied vegetation, while females tend to cluster around accessible resources, leading to a less diverse diet.

We recommend further studies combining dietary analysis with field vegetation monitoring to enhance understanding of resource selection and improve adaptive management strategies for large herbivores.

Photography credit to Aylon Steinberg