Allowable use of 5 key species of alpine rangelands in Lorestan

 Background: Range species have different sensitivities to livestock grazing and this effect sometimes becomes much more important with the help of climatic conditions. If the amount of pasture exploitation is appropriate, Preservation of high-quality pasture and edible species and plant composition, as well as the durability of production in the pasture ecosystem, are guaranteed. Therefore, the knowledge of the amount of production and the allowable use is considered one of the basic information in the management of these ecosystems. This article was written with the aim of determining the allowable use of key species of alpine rangelands.   Methodology: To determine the allowable use of the species, the number of 40 average stands of the species Astragalus curvirostris – Bromus tomentellus – Festuca ovina – Onobrychis melanotricha, Picris strigosa Selected. This project was carried out for 5 years (2011-2016). In such a way that stands number 1 to 10 without harvest or control treatment, stands No. 11 to 20 were treated with 25%, stands No. 21 to 30 were treated with 50%, and stands No. 31 to 40 were treated with 75%. In addition, another 10 similar plants were selected and after the completion of growth, they were cut off as an annual witness and weighed using an electric scale with an accuracy of 0.01 grams. By adding the obtained from the harvest remaining production at the end of the growing season, the total amount of forage produced by each stand for each year was determined. At the same time as the treatments, other characteristics such as vigority, mortality and plant height were measured and evaluated. After completing the statistics, this data was collected at the level of 40 hectares of fenced and existing Exclosure, the data were analyzed using MSTAT-C specialized software.   Results: The results showed that the production of O. melanotricha species increases by 25% it has more regrowth, but harvesting 50 and 75% causes the stands die. In Bromus tomentellus species, harvests of 25, 50 and 75% increase the production of Bromus plant compared to no harvest (Exclosure). In the study of the effect of different harvesting treatments on production, Festuca ovina has shown more resistance to harvesting than other species. But by comparing the annual production averages, the production in the control bases and the 75% harvest treatment is in a higher class than the 25% and 50% harvest treatments. A. curvirostris species is sensitive to heavy grazing and the continuation of heavy grazing will not complete its full growth in the coming years. Therefore, it should not be grazed more than 50%, but we will get the best results in light grazing or 25%. It was found that the species P. strigosa is not very sensitive to grazing in the flowering stages and after, but it is very sensitive to grazing in the first season. If the primary leaves are completely removed, the plant will die at the same stage and in the early stages of vegetative growth, it cannot tolerate even a 25% harvest rate.   Conclusion: In examining the interaction effect of species, time and percentage of harvesting, in short, the allowable use, In short, allowable use of species can be expressed as follows. F. ovina is the most resistant species to harvest aerial organs and up to 75%. O. melanotricha 25%, A. curvirostris 25 to 50%, B. tomentellus 50% and P. strigosa 25 to 50% can tolerate. Of course, observing the grazing season is very important.