Habitat conditions and plant-environment relationship in some arid and semi¬arid lands character plants (case study: Shahriyar Rangelands, Tehran Province)

In order to obtain an optimum management of natural resources, determination of variables that control plant presence and distribution is needed. In the present research, the relationship between some character plants of drylands and some soil and environmental variables were investigated. After primary survey and selection of main plant species, sampling was done in each vegetation type within 3-4 transects (200 m length) by randomized-systematic method. Dominant species included Tamarix ramosissima, Salsola kali, Phragmites australis and Ephedra distachya. Vegetation sampling was done in 200 plots and soil sampling was done from two depth 0-20 and 20-60 cm in 38 plots. SHAZAM 10 package was used to find the logical relationship between plant species and environmental variables. The statistical pattern for this research was based on qualitative function. Therefore, logic function was evaluated. Results show that for T. ramosissima, potassium in the first depth and available water in the second depth; for S. kali, available water in the second depth; for P. australis, pH in the first depth and organic matter in the second depth, and for E. distachya, saturated moisture in the first depth and available water in the second depth have the most important role in plant presence and absence probability.