DNA macrobarcoding reveals seasonal differences and spatial heterogeneity in the diet of Chinese Milu (Elaphurus davidianus) in China

The Chinese Milu ( Elaphurus davidianus ), a wetland herbivore endemic to China, has been successfully reintroduced and is now distributed across various regions in the country. However, seasonal and regional variations in its dietary preferences remain poorly understood, limiting insight into the species’ survival strategies. This study presents the first application of DNA metabarcoding to compare the diets of both free-range and wild Milu across 10 research sites in China during both dry and wet seasons. A total of 269 fecal samples were analyzed, resulting in 13,060 OTUs and the identification of 689 plant species available for foraging by Milu. seasonality is a key factor driving changes in Milu feeding habits, and that Milu respond to seasonal nutritional stress by significantly adjusting their food composition. Spatial heterogeneity also plays a significant role in shaping dietary variation. The dietary composition of Milu populations varies across different protected areas, and Milu are capable of adjusting their feeding habits according to habitat characteristics. Moreover, wild populations demonstrated higher adaptive plasticity, whereas free-range groups exhibited dietary convergence and reduced seasonal adaptability. This findings mainly inform habitat and feeding management recommendations of Milu.