Journal of Rangeland

Monitoring and interpreting vegetqation changes to various ecological condition and management practices is required to achieve sustainable management in rangeland ecosystems. This study aimed to identify indicator species of grazing impacts in thirty one range places with relatively homogeneous ecological conditions and various grazing intensities in Semi-Steppe rangelands of Feridan- Isfahan. Plant species frequencies in each range site were studied along four perpendiculars 30 meters transects using step point method. Integrated System for plant Dynamics (ISPD) software was used to conduct the ِDetrended Corresponding Analysis (DCA) and Centered Principal Component Analysis (CPCA) on the frequency data. Once it was confirmed that the range places were well distributed along first axis of CPCA, the species frequencies were fitted by Gaussian curves against the first axis of ordination plot. According to the regression analysis results, the species with D-Statistic more than 0.5 and correlation coefficient more than 0.3 were identified as indicator species of grazing impacts. Five out of 34 plant species were quantitatively identified as indicators of grazing impact. Agropyron trichophorum was identified as decreaser, Hordeum bulbosum and Acanthophyllum microcephalum as increasers and Astragalus verus and Cousinia bachtiarica as invaders in the study area. Evaluating the frequency of these indicator species can assist range managers to track any positive or negative changes in grazing values of the vegetation compositions in the study area. They can adapt their management strategies using assessment of these indicator species accordingly.