Determining Range Suitability Using Fuzzy and Hierarchical Method (Case Study: Bagheran Birjand Watershed, South Khorasan Province, Iran)

Evaluating rangelands means to identify and create potential and actual rangelands in order to utilize this valuable natural resource properly. Hence, one of the important factors in rangeland management is to determine range suitability and recognize factors affecting it. Weighted Linear Combination Method (WLC) is one of the most common methods used for locating and Analytic Hierarchy Process (AHP) method is one of the most used methods of criteria prioritization and weighting. The purpose of this study was to evaluate range suitability of Bagheran Birjand watershed area in Southern Khorasan Province, Iran using AHP-Fuzzy method in a region with an area of 11879 ha in 2014. For this propose, in the environment of Geographical Information System (GIS), the maps of factors affecting the suitability (slope, production, erosion, quality of water resources, water need estimation percent and distance from water sources) were prepared. Data were standardized using fuzzy method and for weighting the criteria, the Analytic Hierarchy Process method was used. The results of AHP-Fuzzy model based on the weighted linear combination showed that 55.43% of rangelands were in suitability class of moderate suitability (S2), 9.55% of the lands were in suitability class of low suitability (S3) and 6.21% of the lands were in non-suitability (N) class. So, the limiting factors in this model for sheep grazing in the study area are water resources, high slope and vegetation.