بررسی تاثیر قرق بر وضعیت و گرایش مراتع طبیعی مناطق مختلف اکولوژیک (استان لرستان)

Rangeland exclosures is one of the improving operations performed by general administration of Natural Resources in each province, to a great extent every year. Its being effective, however, has not been exactly examined up to now. Therefore, this project was established to deal with the effects of enclosure on the condition ad trend in alpine rangelands of Zagros Mountains. It was established at 1960 meters above the see level, having an average annual rainfall about 777 mm. through and the establishment of a new exclosure in 1997. This was established beside the research center for Rangeland Plants of Zagheh, being about 31years old. Permanent Quadrates with the dimensions of 50*60 cm. were formed on the assumed transects so that two parallel transects, being 30 m. long and 5 m. distance, were established both inside and outside the exclosure in which the Quadrates were about 1.5 m. distance from each other. Applying them and also their cutting and weighing in one square meter plots, such parameters as density, canopy cover, litter, gravel and bare soil were measured inside and outside of the exclosure. The rangeland condition determined each year. The trend was also determined, using common method like trend balance and scoring such parameter as vegetation and soil. Results showed that in the end of study, the canopy cover and the composition of desire plants was significantly more than first year. There were greater inside than outside also. The canopy cover of grasses such as Bromus tomentellus, Agropyron trichophorum and Hordeum bulbosum increased inside of exclosure. In the end of study, inside forage production was significantly two fold of the first year and about 30 percent more than outside. In the end of study, canopy cover of decreasers were about four fold of first year and four fold greater than outside too. Increasers canopy cover were two and half fold, more than first year, but there were not differed considerably from outside. Invaders decreased inside and increased outside. Soil was protected more after seven years, inside of exclosure. Precipitation affected all parameters, including canopy cover but the correlation coefficient between them was not statistically significant. Inside range condition changed from poor to fair but it remained to very poor, outside of exclosure.

Keywords:

بوم شناختی , مراتع طبیعی , لرستان , قرق , تاج پوشه , چمنیان دایمی ‭bromus tomentellus , ‬چمنیان دایمی ‭hordeum bulbosum , ‬بارش , پوشش گیاهی , خرم آباد