Effects of different harvesting intensities on forage production and other characteristics of Bromus tomentellus Boiss. in Gavanban Rangelands of Kermanshah Province

Rangelands cover about half of Iran’s territory with unique ecological characteristics. Understanding these characteristics is an essential need for any management in these arenas. In this regard, the present study was carried out to evaluate the intensity of grazing on vegetative and reproductive characteristics of Bromus tomentellus, as a key species in the rangelands of Gavanban in Kermanshah province during four years. At first, a reference area of one hectare was selected and fenced. Simulation method was used in this study. Treatments included four harvesting intensities of 25, 50 and 75% and control on Bromus tomentellus. In each treatment, 40 individuals of species were selected. The effect of exploitation on phenological characteristics such as height, number of flowering stems, vigor, vitality, collar area, forage production and other characteristics were evaluated. All data were analyzed using combined analysis of variance in a completely randomized design. Results showed that production of Bromus tomentellus did not differ statistically in response to different harvesting intensities, and up to 75 percent of the species could be harvested; however, in some cases, morphological traits were affected, leading to decreased number of flowering stems, and increased collar diameter over the years. Also, it did not have any significant effect on height and vitality. In other words, the regeneration of species harvested decreased (due to reduction in the number of flowering stems). However, 75% harvesting intensity caused increased collar area.