Document Type : Research Paper
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Abstract
Desertification refers to land degradation in arid, semi-arid, and dry sub-humid region. It is a global environmental problem with political and socio-economic consequences. Land degradation occurs as a result of impoverished vegetation cover that may lead to a progressive and irreversible reduction of the biological or economic productivity. Overgrazing may cause degradation of soil and vegetation. Degradation of vegetation and soil in dry lands, sometimes called desertification, is thought to be a serious threat to the sustainability of human habitation. Therefore, the intensity of grazing can serve as an index of environmental pressure. The Miandehi region, located in the Northeast Iran, has been selected as a test area to assess livestock pressure. Present paper assessed the pressure of livestock within the studied area using GIS. FAO-UNEP model (1984) proposes the use of a ratio of potential carrying capacity to present livestock density as an estimate of pressure of livestock. This method has been adopted with some modifications for the present study. Therefore, maps of the hazard of pressure of livestock were prepared after overlying and calculating different parameters in GIS. According to the final map of pressure of livestock in Miandehi region, areas of no hazard, slight hazard, severe hazard and very severe hazard comprised respectively 21.3, 5.6, 9.8 and 63.3 % of the study area. Results showed that areas under very severe hazard dominate Miandehi (63.3 % of total land).
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