Quantifying the Rate of Environmental Factors Effect on Astragalus verus and Agropyron trichophorum Using Decision Support System and Multivariate Analysis of PCA

Vegetation cover over time and space is the result of interactions betweenvegetation cover and environmental factors. Changes occurred in range covers are caused bymatrix dominance, one of the most important environmental factors. Decision support system(DSS) could be used for determining the rate and importance of each factor. Actually, inmethods based on DSS, relations between input and output factors are identified. Up to now,various methods have been used in analyzing multivariate decision that includes binarycomparison method that has been used in this study. This method has become one of the mostcommonly used methods of multivariate decision making and has been used for resolvingunstructured issues in various human areas such as agriculture and natural sciences. In thisstudy, nine sites were selected in west of Isfahan, Iran, then different vegetation cover andenvironmental factors were examined in each of these sites. By analyzing main components,effective factors and impact of range were identified, finally using analytical hierarchicalpattern (AHP) model, the quantity of effective factors on Yellow Astragalus and grass siteswas determined. The rate of limestone of soil and slope factor in Yellow Astragalus were 14.4and 14.2%, respectively, which have the greatest effect and with regard to grass transmittal,Soil limestone and soil acidity influenced 20 and 13.2% of variation, respectively.