The assessment of management practices on rangelands exploitation using state and transition model in central arid regions of Iran

Rangeland management in arid and semi-arid regions requires comprehensive attention to ecological processes and consider the interrelationship of those processes. considering discard the theory of climax and rangeland succession model in recent years especially in arid regions and shrub lands, the new theory known as the state and transition model is taken into consideration by natural sciences and environmental specialistsb in the world. in present study, state and transition model and its application in rangeland management will be discussed and wil be peresented a case study of iran for more description. as a case study, nir rangelands of yazd province will be introduced. in this rangeland, both status of enclose and grazing livestock evaluated and grazing livestock has been introduced as threshold of these two conditions. rangelands of arid regions are biologically fragile and in the case of little degradation, a long time will be needed for compensation. the definition of different situations, thresholds, transitions and indicators will help managers to follow change trend among different plant communities and establish an ideal community. but due to very slow and very small changes in arid regions rangelands, use of models in these areas is not possible.