Floristic Structure and Vegetation Composition of Boralan Mountainous Rangelands in North-Western Azerbaijan, Iran

Recognition of habitats and conditions of species presences in different situations can be effective in proper utilization of vegetation. Little is known about the vegetation composition of Boralan Mountain region located in North West of Iran in the border of Turkey and Azerbaijan with the altitude range of 800-2000m. The aim of this study therefore was to investigate the floristic composition quantitatively and analyze the vegetation response to altitudinal gradient conditions of mountain. Firstly, plants were collected by floristic field survey and identified using the floras. To investigate the relationship between the gradients of elevation and vegetation, two transects of 100m were established at every 100m of elevation belts and the percentages of canopy cover and density of species were totally recorded in 20 plot samples using a random plot design. Plant community zones were characterized on the basis of species’ cover dominances using cluster analyses. According to this study, the area includes 108 species that were classified into 26 families. Totally, Poeaseae and Asteraceae with 40 percent cover dominance were more frequent than other families. Based on species similarity of elevation classes, the cluster analysis led to four vegetation type groups. The grass group and the shrub group occurred on high altitudes at 1900 m and lowland sites at 800-1300 m, respectively. The results also showed that elevation variations had considerable effects on diversity and richness indices of vegetation groups with the highest number of species at high altitudinal belt. It seems that precipitation improvement and low grazing intensities has mainly caused these changes.