مقايسه توانايي روش هاي مختلف تعيين وضعيت مرتع در تفكيك وضعيت هاي مختلف در دو رويشگاه استپي و نيمه استپي

Comparison of the Ability of Range Condition Methods to Classify Range Condition in Steppe and Sub-steppe Regions

Range condition identified as range health and compares the piresent status with the final potential status of ranges. Evaluation of range condition on the basis of clement theory is routine in Iran. Capability of current range condition methods therefore* is the subject of this research. Two sites were selected one in sub-steppe and another in steppe regions in Ferydon shahr and Maimeh respectively. Two regions are located in Isfahan province. Vegetation type of sub-steppe is Grass-Astragalus and steppe Artemisia herba Alba. Looking through soil and vegetation status of the study sites they were put into three condition classes* good* fair and poor as benchmark. Within each class three replicates of five transects were places across environmental changes gradient. Data were collected from l*1.5m and l*2m plots on sub-steppe and steppe sites respectively. Having 25 plots alongside of each replicates totally data were collected during 2003 to 2004. Seven methods were selected to be tested namely 4factorsʹ modified 4factor< 6factorsʹ modified 6factors< vegetation and soilʹ African and finally observation and estimate. Taken the instruction of each method into accountʹ the average score of range condition and its status for the time period of the study were calculated. Accuracy and precision were criteria on that, basis ability of the methodʹ to evaluate range conditionʹ were assessed. Results show that 4factors as well as modified 4factors methods are the most suitable ones for sub-steppe regions. None of the tested methods were producing accurate and precise range condition results in steppe regions. Low performance of the methods could be related to their originʹ ecological differencesʹ usage of unsuitable indicatorsʹ neglecting the site potential and the role of management. This study suggests revision of the methods in light of local (or national) site conditions. New method should have an ecosystem base and be able to discriminate between site potential and managerial effects.