Can the rangeland health model interpret the function of semi-steppic area (Iran)?

ABSTRCT: Rangeland with the natural potential are consider as an important resource in bestial and crop production. In order to interpret the indicators of rangeland health model and to specify the structural and functional attributes of the ecosystem, the rangelands in the Polour region, as semi steppic region, were selected. Three attributes of the rangeland ecosystem (i.e. soil/site stability, hydrologic function and biotic integrity) were assessed using the descriptive model of the rangeland health. To this end, 17 ecologic indicators were selected. The results showed that in the evaluation area the change in the plant compositions, the dominance of the invasive, the increase in the bare soil, the appearance of wind erosion and the collapse in the topsoil resistance were all characterized as the factors decreasing the rangeland health in the area so that all the three attributes of the rangeland ecosystem were below the threshold line of integrity at the extreme compared to the ecologic reference area. The results point out that this model has produced different assessments in the sites with equal ecologic conditions but unequal management practices. Moreover, the descriptive categories of indicators as well as the attributes have the ability to identify the differences in the evaluation area.