Different indices of functional diversity as: functional richness (FRic), functional evenness (FEve) and functional divergence (FDiv), could help to understanding of the relationship between plant diversity and ecosystem function. Therefore, this study was aimed to evaluate changes in species diversity and functional diversity of vegetation under different grazing intensities in relation to soil physic-chemical properties in Changizchal rangelands, Mazandaran province, Iran. During the spring and summer of 2014. Three functional traits including Specific Leaf Area (SLA), Vegetation Height (VH), and Leaf Dry Matter Content (LDMC) were measured in three grazing intensities (low, moderate and high). Taxonomic diversity was quantified using several indices including Species richness (S), Shannon (H), Evenness (E) and Simpson (D). In addition, functional diversity was quantified using single trait-based (FDvar) and multi trait-based indices (functional richness (FRic), functional divergence (FDiv), and functional evenness (FEve). The result showed that functional richness and species richness increased at moderate grazing. Similarly, the higher values of FDvar of the SLA were observed in a moderate grazing. Whereas, the FDvar of VH values significantly increased in light grazing. The low grazing induced increase in the FDive and FEve coupled with decreasing soil organic carbon (P<0.05). The FDvar for SLA had a positive relationship with soil N and P in low grazing. Stable grazing on Changizchal rangelands tends to increase competition for soil N and P, resulting in an increase in the functional richness in grazed plant communities. The present study highlights the potential importance of low to moderate grazing intensities in mediating and reducing competition between plants for nutrient resources. Manuscript profile