The study and comparison of the vegetation at elevation gradient in two medium and cold steppe zones in northeastern part of Golestan province

Abstract The systematic and scientific study of plant distribution along the altitudinal gradient can be introduced into the natural habitat by changes in altitude leads. In this study, the presence of plant species on twenty 100 m² transects and sampling points (10 points), along a gradient of 90 to 1476 m with 200 m changes above sea-level were recorded. TWINSPAN analysis was carried out using PC-ORD 5 based on the similarity and dissimilarity of the transects sampled, were grouped. To investigate the relationship between the vegetation and environmental factors (altitude, rainfall and slope), the original Principle Component Analysis (PCA) was used. The environmental factor of elevation above sea level affects the separation and distribution of the species groups meaning that one or a few plant species can represent a range of special ecological characteristics.