The most important climatic factors affecting distribution of Zygophyllum atriplicoides in semi-arid region of Iran (Case Study: Isfahan Province)

Zygophyllum atriplicoides is one of the important species of Iran rangelands that has special importance owing to some properties like high distribution rate, coverage percentage, density, and plant biomass that make it possible to supply a part of forage needed by livestock during spring and winter as well as to avoid soil degradation against water and wind erosions. This research tries to study the most important climatic factors affecting distribution of Z. atriplicoides using multivariate statistical methods and selecting ecological important 69 variables in Isfahan province. Four factors, such as cooling temperature, precipitation, cloudiness, and wind were determined by the factor analysis method and variables variance of 34.45, 29.43, 11.79, and 9.06 were obtained, respectively totally represents 84.74 of the changes. The mean of factor scores and climatic variables in three populations of the Z. atriplicoides species as the dominant species, Z. atriplicoides species as the associated species and regions without the Z. atriplicoides species were determined. Furthermore, the factor score matrix was used as the input of the hierarchical cluster analysis and 6 climate zones were identified in Isfahan province. The most important climatic factors affecting the species distribution were determined by incorporating the vegetation map, factors map, and climatic zones. The effect of altitude was also analyzed in the species distribution. Results showed that the temperature factor is the most important climatic factor affecting distribution of the species in the Isfahan province and the precipitation factor influences the species distribution. Also, the effect of altitude and soil salinity on analysis of Z. atriplicoides populations could not be ignored.