This study sought to develop a Decision Support System (DSS) for assisting range managers to
detect range condition and make informed decisions about Feridan County rangelands. All plant
species frequencies were measured in 31 range sites with various grazing histories using step point
method. Four hundred points along four perpendiculars 30 meters transects were measured in each
site and grazing indicator species were identified using grazing gradient analysis. The range
conditions of the sites were determined by evaluating the frequencies of indicator species along
grazing gradient using Resource Environment Data Information System (REDIS). The best
management practices and ecological interpretation for each range condition classes were then
inserted into the REDIS model. The end users can import the indicator species frequencies of a
selected site into the REDIS model and obtain the required information about range condition class,
ecological information and management options. According to the results, the frequencies of six
range species in the study area can appropriately determine range condition classes quantitatively.
The model performance was then evaluated by comparing the range condition classes of 12
independent sites by REDIS model and ‘Four Factors’ method. The REDIS model had an accuracy
of 91 percent. The mangers can save the condition position of a selected site along a condition
gradient in REDIS model; hence they could simply monitor the range condition changes of the
studied site.