Sustainable rangeland management using fuzzy logic: A case study in Southwest Iran

While there is no consensus on a definition, it is widely recognized that the concept of sustainability has economic, environmental and social dimensions. We used fuzzy logic as a well-suited tool to handle the vague, uncertain, and polymorphous concept of sustainability. For recognizing the major important indicators in defining sustainability in range management, several semi-structured interviews with an open-ended questionnaire in three different areas of the Fars province in Southwest Iran were held. Pastoralists’ experts recognized that sustainability in range management is a function of three major components (inputs) which are the stocking rate in a pasture, the amount of plantation density per hectare, and the number of pastoralists who live in a pasture where the output of the model is the Right Rate of Stocking. Based on pastoralists’ insights we developed a model called Equilibrium Assessment by Fuzzy Logic (EAFL) which provides a mechanism for assessing sustainability in rangeland management. The EAFL model exhibits three important characteristics. First, it permits the combination of various aspects of sustainability with different units of measurement. Second, it overcomes the difficulty of assessing certain attributes or indicators of sustainability without precise quantitative criteria and, third, the methodology is easy to use and interpret. An important outcome of the EAFL model is that all the pastoralists’ experts agree with this conclusion that the current, real stocking rates are much higher than the optimal stocking rates.