Investigation on relationship environmental factors and grazing intensity with vegetation cover in Khoy rangeland ecosystems

In range management, recognizing environmental factors and their impacts on plant covers are very important. This research was conducted in Dizaj and Batchi rangelands of Khoy in order to evaluate and detect the most important environmental and management factorsaffecting plant distributions. After distinguishing indicator plant types in the regions, random-systematic-methodsampling was conducted along 100 m transects within 1 m2 plots, and the density and percentage of canopy of plant species were collected. The area of samples and the numbers of samples were determined on the basis of dominant plant canopy variations and statistical methods respectively. Then, in the begining and end of this research each transect of soil sampling from depth of 0-15 cm was taken. Moreover, information about elevation AMSL (above mean sea level), slope, aspect and grazing intensity was recorded. The soil characteristics such as soil texture, caco3, pH, EC, saturated humidity and organic matter were measured in laboratory. In the final step, to assess the relationship between environmental factors and plant distribution PCA was used, and to evaluate the relationship between species and stated factors CCA was applied. The results demonstrated that the effects of environmental factors on plant distribution were not the same and the most important effective factors in the distribution and establishment of dominant plant species like and Artemisia were soil texture, grazing, precipitation, ASL, aspect and EC. The results also illustrated that environmental factors had significant effects on plant control and distributions. But undesirable effects of human activities like grazing intensity, on sustainablemanagement of rangeland were undeniable.