Tree Species Diversity Across Altitudinal Gradients in the Persian Oak Forests of Lirabi, Ardal County, Iran

Altitudinal variation plays a key role in shaping forest biodiversity, particularly in mountainous ecosystems such as the Zagros range. This study explores the structure and composition of woody plant communities across three elevation classes in the Lirabi Forest of Ardal County, southwestern Iran. Using a systematic random sampling approach, ۴۰ plots (۳۰ x ۴۰ m) were established to record species abundance and physiographic variables. A suite of biodiversity indices including richness (Margalef, Menhinick), diversity (Shannon-Wiener, Simpson), evenness (Pielou, Sheldon), and dominance (Berger-Parker)-was applied to assess ecological patterns. Statistical analysis revealed no significant differences in species richness or overall diversity among elevation classes. However, evenness indices varied significantly, with mid-elevation plots (۲۰۰۰-۲۱۰۰ m) showing greater species balance and reduced dominance. These results highlight the ecological sensitivity of evenness metrics and suggest that intermediate altitudes offer more favorable conditions for species coexistence. The consistent dominance of Quercus brantii across all elevations underscores its structural role in these forests. Findings from this study emphasize the importance of mid-elevation zones for biodiversity conservation and suggest that forest management strategies should incorporate evenness-based monitoring to better capture ecological dynamics in Zagros oak ecosystems.

کلیدواژه ها:

Biodiversity ، Elevation Gradient ، Persian Oak ، Zagros Forests ، Lirabi