بررسي عوامل محيطي مؤثر بر پراكنش چند گونه گياهي مناطق بياباني (مطالعه موردي: حاشيه كوير چاه بيكي استان يزد)

Environmental effective factors on distribution of arid plants (Case study: Cbabbyki region ofYazd province)

The aim of this research was to study the relationships between presence of plant species and environmental factors in Chabeyki region of Yazd province. After delimitation of the study area, sampling was performed using randomized-systematic method. Within each type 5 parallel transects with 500 m length, each containing 50 quadrates (according to vegetation variations) were established. Quadrate size was determined for each vegetation type using the minimal area method. Soil samples were taken from 0-30 and 30-80 em in starting and ending points of each transect. Measured soil properties included gravel, texture, available moisture, saturation moisture, organic matter, lime, gypsum, pH, electrical conductivity and soluble ions (Na+, K+, Mg2+, Ca2+, Cl, co; ,HC03 and Soj-). Logistic regression technique was used to analyze the collected data. The results showed that the vegetation distribution is mainly related to soil characteristics such as gravel, saturation moisture, EC, pH, and lime. The presence of Cornulaca monocantha and Calligonum comosum has negative relation with saturation moisture and positive relation with gravel. Haloxylon aphyllum has also positive relation with pH. While, the presence of Seidlitzia rosmarinus has positive relation with Lime. EC has positive relation with the presence of Tamarix ramosissima.