Abstract
Climate warming promotes alpine plant migration to higher elevations, yet how they adapt via stoichiometric homeostasis remains unclear. We measured plant C, N, and P traits and homeostasis across community and functional group levels in three alpine vegetation types-meadow (3200-3400 m), shrubland (3400-3700 m), and cushion vegetation (3700-4400 m)-along an altitudinal gradient in the northern Qilian Mountains, Tibetan Plateau. Shrubland, as ecotones, had higher soil C and N, with plant communities showing the highest N and N:P but lowest C:N. At the functional group level, Poaceae (Gramineae) and forbs had the highest N and N:P, while Cyperaceae had the highest P in shrubland. Notably, Cyperaceae in shrubland exhibited weak P and C:P homeostasis. Poaceae (Gramineae) were mainly influenced by soil, Cyperaceae by climate, and forbs by elevation. Structural equation modeling showed elevation indirectly affected stoichiometry via climate and soil; climate influenced nutrient contents, while soil controlled C:N:P ratios. These results reveal diverse nutrient regulation and survival strategies in alpine plants, enhancing understanding of adaptation and community assembly under climate change.