Vegetation Ordination of Steppic Rangelands in Relation to the Edaphical & Physiographical factors (Case Study: Abadeh Rangelands,Fars)

this research, we studied Fars steppic rangelands in relation to the edaphical and physiographical factors using ordination and classification techniques. A region with 27295.4 ha area and elevation ranging from 1900 to 2400 m above sea level has been chosen and then in each 100 m interval the density and abundance of species was recorded in 268 quadarats (1m2) along four transects (300m in length) and eight transects (100m in width). Using Sorenson similarity index and land shape map in ILWIS, 106 soil profiles were sampled for physical and chemical characteristics such as soil texture, structure, organic carbon, K, P, N, pH, EC,Caco3, Caso4, humidity and also for physiographical factors such as height, slope and aspect. Using DCA and CCA and classification in TWINSPAN we found 22 ecological groups. The most important factors were soil texture, pH, percentage of humidity, P, Caso4, K, Caco3 for plains and slope, aspect and precipitation for terraces and uplands.