Study of Methods Measure Density of Astragalus verus Olivier (Case Study: Isfahan Fereydoonshahr Rangeland)

In order to analyze density measurement methods, a study site with four replicates in Fereydoonshahr characterized with vegetation type Astragalus verus-Bromus tomentellus was selected. In each site (an area with 5000 m2 in dimension 50*100m), real density was calculated by counting all individuals of Astragalus verus. Samples were taken in random-systematic manner. Within each replication, five transects 100 m in length were established and given sample size for each method, some points were selected in randomized manner and density measurement methods(Closest Individual Method, Nearest Neighbor Method, Random Pairs Method, Point Centered Quarter Method, Wandering Quarter Method, Angle Order Method, Corrected Point Distance Method) were implemented. Difference between density measurement methods by control method counting was evaluated using LSD method. According to the results, the closest estimation to control is nearest neighbor one. Point Centered Quarter Method, Wandering Quarter Method, Angle Order Method, and Corrected Point Distance Method showed significant difference to control. The largest and lowest sample size was attributed to Angle Order (33) and Wandering Quarter Methods(125) among others. The regular and T square had longest and shortest measurement times. The nearest neighbor showed the highest accuracy and Wandering Quarter as well as Point Centered Quarter had the least accuracy.