environmental and managerial factors effects on plant species distribution (case study: saral rangelands of kurdistan province)

this research has been done with the aim of explaining environmental and managerial factors that affects on rangeland vegetation distribution in saral rangelands of kurdistan province. after selecting plant types as working area were done sampling from plant types and determined some of plants parameters such as kind and number of plants and cover percentage. various environmental factors such as topographic factors (slope, slope direction and elevation), soil physical factors (depths, soil texture, gravel and saturation moisture) and various chemical factors such as acidity, electrical conductivity, lime, gypsum percentage, organic material, nitrogen, phosphor and potassium) were measured and grazing intensity were considered as managerial factors. after collecting data, the principal component analysis (pca) was used to determine relationship between vegetation cover and environmental factors by pc-ord software. the results showed that among various environmental and managerial factors affecting in plant distribution, soil depth, grazing intensity, elevation, sand, gravel and silt percentage have the highest correlation with principal component analyses. these factors are the most effective factors on plants type distribution in rangeland ecosystems. among effective soil factors on distribution of plant communities in this study, soil physical factors have greater impact than soil chemical properties. physiographic factors including elevation and managerial factors including grazing intensity have considering effect on distribution of plant communities.