recognizing of the most important change in the qualitative and quantitative components of vegetation in consequent of exclusion kalpush plain rangeland using multivariate analysis

considering the importance of vegetation changes and awareness of its destruction or improvement trends in programming and its proper managing of utilization, this study was conducted in order to survey the effects of grazing on the qualitative and quantitative components of vegetation (including life form, growth form, palatability class, plant families and species diversity) and recognition their most important changes in both grazing and enclosed sites in kalpush plain, golestan provience. for this purpose, samples were taken via 78 plot 1 square meter in a randomly- systematic method. mean comparison of the components and recognition of the most changeable components in consequent implementing grazing management were done with t-student test and principle component analysis (pca) respectively using spss software. according to the vegetation study, 13 species belong to asteraceae family and 10 species to poaceae family and there are 69 herbaceous species, 13 grass species and 5 shrubs species of plants in this region. the results of t-student test indicate an increase in relative density of therophytes and class i plants, and decrease in cryptophytes and class iii in the enclosed. also the results point out that grazing has caused increasing in the relative canopy of shrubs and champhyte and decreasing in therophytes, forbs in the region. comparison of relative density and canopy cover of plant species in two sites showed a relatively good effect of rangeland enclosing in increasing of the density, restoration and recovery of species composition and diversity. principal component analysis also showed that the most changeable components in consequent of rangeland enclosing were forbs, hemicryphtophyte, therophyte, appiacea and brassicacea families in positive and shrubs in negative of first axis. also the papaveracea and asteracea families have the most incremental changes in the second component.