effects of topographic and edaphic characteristics on distribution of plant species in eshtehard rangelands

the objective of this research was to study the relationships between edaphic and topographic factors with distribution of plant species. for this purpose, current study was conducted in eshtehard rangelands of tehran province. the sampling method was randomized–systematic and in each sampling unit, three parallel transects with 750 m length containing 45 quadrates (according to vegetation variations) were established. quadrate size was determined for each vegetation type using the minimal area; hence suitable quadrate size for different species was determined 1*2m (2 m2). soil samples from the beginning and end of each transect at two depths 0-30 and 30-80 cm were taken and the measured soil properties included gravel, texture, organic matter, lime, ph and electrical conductivity. to analyze the environmental data, pca was considered. the results indicated that gravel, texture, ec and lime play the main role in the distribution of plant species.