Study of exclosure effect on vegetation characteristics of Rozband rangelands in Qom province

The study of changes in rangeland vegetation at regular intervals and awareness of rangeland conditions is one of the important issues for planning and proper management of rangeland utilization. The present study was designed to study changes in the vegetation features in the grazed and exclosured rangelands in the Razband of Qom province. The vegetation measurement was performed in the form of a pair of transects with a distance of 10 meters from each other. Each pair of transects contained 20 plots. The plots with dimensions of 1 × 1 m were spaced 3 m apart and 10 were placed on each transect. Finally, 240 plots (120 plots inside and 120 plots outside of the enclosure) were evaluated. The data analysis was done by SPSS software and the diversity and species richness were performed using PAST software. Out of a total of 8 plant families, six families were significantly different inside and outside of the exclosure. The exclosure in the study area was significantly increased canopy covered by shrubs and forbs, while the grasses showed no significant difference. Chamephytes, hemicryptophytes, terophytes and class I and III species showed a positive and significant response to exclosure. The T-test for species richness and diversity indices showed that Simpson and Shannon - Wiener diversity indices and Margalef richness index had significant differences. The Menhinick's richness index and evenness index were not significantly different inside and outside of the exclosure. Besides, the RDA analysis to evaluate the impact of exclosure on all of the plant species in plots showed that exclosure had a significant effect on the vegetation (P=0.001, F=29.66). The results of this research showed that a short-term exclosure can cause reconstruction and vitality renewal of plant species such as Bufonia macrocarpa and Artemisia sieberi in the arid rangelands of Qom.