Lichen beta diversity variations at different grazing intensity in Semirom mountainous rangelands

Nowadays, biological crusts, including lichens, are used as a living biological indexes. The Main objective of this study is evaluation of lichen diversity trends at differences grazing intensity in the mountain rangelands of Semorom in Isfahan province. The lichen diversity is dependent variable and grazing intensity (consists of 5 stoking rate 1, 1.5, 2, 2.5 and 3 animal unit per hectare) considerd as independent variable. Each stoking rate studied along 4 years by implementing 5 management scenarios (grazing and ungrazing alternatively and consecutively). The presence and absence of lichens was performed by random sampling method using transects and sampling units. The lichen diversity analyzed by PAST software and the relationship between variables was calculated by SPSS. The result showed that the lichens diversity is a good indicates of pressure on rangeland ecosystems. In management of rangeland ecosystems, lichen diversity can be used as an ecological indicator for rangeland ecosystems under pressure or non-pressure. Also, the best grazing management scenario for this area is suggested based on the variation of lichen diversity, alternating grazing scenario (every one year between grazing and resting depending on rangeland status and range method).