Sequential stable isotope analysis reveals differences in dietary history of three sympatric equid species in the Mongolian Gobi

Competition among sympatric wild herbivores is reduced by different physiological, morphological and behavioural traits resulting in different dietary niches. Wild equids are a rather uniform group of large herbivores which have dramatically declined in numbers and range. Correlative evidence suggests that pasture competition with livestock is one of the key factors for this decline, and the situation may be aggravated in areas where different equid species overlap.
The Dzungarian Gobi is currently the only place where two wild equid species coexist and share the range with the domesticated form of a third equid species. In the winter-cold Gobi desert pasture productivity is low, highly seasonal, and wild equids additionally face increasing livestock densities.
We used stable isotope chronologies of tail hairs to draw inferences about multi-year diet seasonality, isotopic dietary niches and physiological adaptations in the Asiatic wild ass (khulan), re-introduced Przewalski's horse, a...