Preference Value of Plant Species in Middle Alborz Region of Iran by Sheep

Preference value means the animal preferring to eat a plant and different species do not have the same preference in different growth stages. Accordingly, by the use of preference value of forage plants in the rangeland management, grazing capacity of rangelands can be determined to achieve the optimum performance of livestock and to guarantee the stability of rangeland ecosystem. In this study, the plant preference value was determined by the preference index in semi-steppe rangelands of middle Alborz Mountains of Iran during the years of 2007- 2010. The results showed that during the studied years, the year of 2010 had the lowest preference value and also had a significant difference with the other years and we can say that the first month of these years had the highest value and there were significant differences among these months. Also, a fact about species is that there are significant differences among them and the highest value was related to Thymus kotschyanus and Scariola orientalis. Therefore, these two species have a complete preference value during the studied months and years.

Preference value, rangeland, species, Middle Alborz