The Effects of Wildlife (Deer) and Livestock (Sheep and Goat) Grazing on Species Diversity and Richness, and Plant Composition in the Steppe Rangelands of Mehriz

To assess the impact of grazing on the diversity, richness and evenness of vegetation, several indices and information on plant composition are necessary because of their different sensitivity to grazing gradients and kinds of herbivores. Thus, the purpose of this study was to compare these indices between two wildlife and livestock grazing sites in steppe rangelands of Mehriz. Sampling was performed using a random systematic method in April 2012 (10 transects of 100m and three plots of 2m2 were placed on each transect on each site). The species name, plant families, longevity and canopy cover percentage were determined in each plot and along each transect. Finally, the data were analysed using an independent sample t-test. The results showed that the canopy cover percentage of Colchicum kotschyi, Iris songarica (p<0.05) and Stachys inflata (p<0.01) significantly increased while the percentage of Artemisia sieberi, Stipa barbata (p<0.01) and Scorzonera sp. (p<0.05) canopy cover was revealed to have significantly decreased in deer grazing areas. The results of a statistical analysis showed that deer grazing has caused plant diversity indices to increase such as Shannon, Simpson and evenness (p<0.01). However, the Margalef and Menhinick indices did not show any significant difference between the two sites.