Effective environmental factors on distribution of grass species in Taleghan rangelands of Tehran province (Iran)

The current research was carried out to find the most effective environmental factors in plant species distribution. For this purpose, study was conducted in Taleghan rangelands of Tehran province. Based on vegetation map and field surveys, indicator vegetation types were identified. Within each type, 3 parallel transects with 150 m length, each containing 15 quadrates (according to vegetation variations) were established. Sampling method was randomized systematic. Quadrat size was determined for each vegetation type using the minimal area method. Floristic list and canopy cover percentage were determined in each quadrat. Soil samples were taken from 0-30 cm in starting and ending points of each transect. Measured soil properties included depth, gravel, texture, organic matter, lime, pH, electrical conductivity, nitrogen and potassium. To determine the most environmental effective factors on plant diversity, PCA method was applied. The results indicated that soil depth, texture, organic matter and nitrogen play the main role in distribution of plant species.