Flora, life forms, Chorology and plant diversity of rangelands vegetation in Qezel Ozan- AqDagh altitude gradient, Khalkhal County

Identification of plants in an area is essential for other studies such as ecological research, ecosystem management and plant conservation. In this study, the flora and plant diversity of Qezel Ozan- AqDagh altitude gradient rangelands, Khalkhal County in southern Ardabil province were investigated. For the study of flora, plant samples were collected and identified. Field harvesting were carried out in 2018, then chorology and life form of the species were determined. Then, richness, evenness and diversity indices were measured in the elevation classes. Based on the results, 31 family, 105 genera and 137 plant species were identified in the study area. Asteraceae (25 species), Poaceae (18 species), Fabaceae (16 species) and Lamiaceae (13 species) are the most important family in the region. The palnts life spectra based on Raunkiaer’s method showed that hemicryptophytes and trophytes were the most abundant biological forms in the region with 46% and 35%, respectively. In addition, results showed 47% of the species belonged to Iranian and Turanian vegetative zone. Among the vegetative forms, forbs had the highest abundance (73.72% of species). The results of analysis of numerical indices of species diversity and richness showed that these indices complied the Humped-shape pattern and at the different elevation classes have significant differences. The highest numerical values of diversity indices of Simpson (0.78), Shannon-Wiener (1.87) and richness indices of Menhinic (1.49) and Margalf (2.37) obtained in middle elevation class. The evenness index also showed an inverse relationship with elevation. The results of this study can be used to suggest plant species for restoration of the study area and similar areas.