Data from: Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski’s horses

The Przewalski’s horse (Equus ferus przewalskii), the only remaining wild horse within the equid family, is one of only a handful of species worldwide that went extinct in the wild, was saved by captive breeding, and has been successfully returned to the wild. However, concerns remain that after multiple generations in captivity the ecology of the Przewalski’s horse and / or the ecological conditions in its former range have changed in a way compromising the species' long term survival. We analyzed stable isotope chronologies from tail hair of pre-extinction and reintroduced Przewalski’s horses from the Dzungarian Gobi and detected a clear difference in the isotopic dietary composition. The direction of the dietary shift from being a mixed feeder in winter and a grazer in summer in the past, to a year-round grazer nowadays, is best explained by a release from human hunting pressure. A changed, positive societal attitude towards the species allows reintroduced Przewalski’s horses to utilize the scarce, grass-dominated pastures of the Gobi alongside local people and their livestock whereas their historic conspecifics were forced into less productive habitats dominated by browse.普氏野马（Equus ferus przewalskii）是马科现存仅存的野生马类，也是全球少数几种经野外灭绝、圈养繁育拯救后成功重返野外的物种之一。然而目前仍存在担忧：经过多代圈养后，普氏野马的生态习性，或是其原栖息范围的生态条件已发生改变，可能危及该物种的长期生存。本研究对准噶尔戈壁地区灭绝前及重新引入的普氏野马尾毛的稳定同位素年代序列展开分析，结果显示二者的同位素饮食组成存在显著差异。该饮食转变方向为：从过往冬季兼具混合摄食、夏季专性草食的模式，转变为如今的全年草食性，这一变化最合理的解释是人类狩猎压力的解除。当下社会对该物种的态度已转向积极，使得重新引入的普氏野马能够与当地居民及其牲畜一同利用戈壁地区稀缺的草本主导型牧场；而其历史同种种群则被迫退缩至以嫩枝采食为主的低生产力生境中。