This study focuses on the niche characteristics， interspecific association， and community stability of dominant species in the herb layer under extreme cold and arid conditions on the Ngari Plateau， aiming to provide a research basis for the ecological restoration of alpine desert steppes. The results showed that Stipa purpurea had the widest niche breadth （12.41）. Some species exhibited an asymmetric phenomenon between niche breadth and importance value， with obvious niche differentiation. The average values of the niche overlap index and similarity index were 0.14 and 0.05， respectively， indicating a low overall competition intensity， and species adopted a low-intensity competition survival strategy. Most interspecific associations were not significant， and the average values of the Jaccard index and Ochiai index were relatively low， with species coexisting in a weak interaction mode. The M. Godron model showed that the intersection point of community stability was close to the theoretical stable point （20， 80）， and the herb layer was in a stable successional stage. The study indicates that the community maintains stability through the dominance of wide-niche species， the differentiation of narrow-niche species， and weak positive associations. It is suggested that species with similar ecological habits should be preferred in ecological restoration to maintain interspecific balance.

Ngari Plateau  /  Ecological niche characteristics  /  Niche differentiation  /  Interspecific relationships  /  Community stability