Abstract
Understanding the forage resources that sustain endangered herbivores under strong seasonal constraints is essential for effective habitat restoration. Przewalski's gazelle (Procapra przewalskii), an endemic ungulate restricted to the Qinghai Lake Basin on the Qinghai-Tibet Plateau, persists in fragmented subpopulations facing pronounced seasonal bottlenecks in forage availability. Here, we investigated seasonal dietary strategies and forage selectivity across nine geographically isolated subpopulations by integrating fecal microhistological diet analysis with vegetation surveys and availability-corrected Jacobs' electivity indices. Gazelle diets were compressed in early spring, dominated by graminoids (Poaceae and Cyperaceae), but expanded substantially during summer, with increased contributions from Fabaceae and Rosaceae and significantly higher richness and niche breadth. Electivity analyses revealed a hierarchical spectrum of preferences structured around core foundation taxa consistently selected across seasons, complemented by season-specific priority resources during spring bottlenecks and summer abundance. Basin-wide pairwise ranking further identified seasonal priority forage taxa with varying spatial consistency across subpopulations. These findings provide a seasonally explicit framework for identifying key forage targets and guiding evidence-based restoration and zoned management within Qinghai Lake National Park, offering transferable insights for conserving endangered plateau herbivores under fragmentation and strong seasonal resource limitation.