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Background and Objectives: Determining the minimum number of samples and parameters required for acceptable results is crucial in rangeland vegetation studies. The common methods for determining Article history: sampling intensity are graphical methods and statistical characteristics. This RReecveisievde:d:101.00.40.32.2020222 study aims to compare these two methods in desert ecosystems dominated Accepted: 16.04.2022 by Salsola richteri and Ammotamnus lehmannii in South Khorasan. Methodology: An area of 100 hectares was randomly sampled using 10 Keyods: initial plots of 1010 meters. The number of sampling units was determined Sampling intensity, species accumulation curve, Cochran's sample size formula, coefficient of variation. using conventional graphical methods and the species accumulation curve (SAC). Statistical methods including the first and second Cochran's sample size formula, Yamane's sample size formula, confidence interval, and coefficient of variation (CV) were also used. All statistical calculations were performed in the biotools package in R software environment. Results: The appropriate number of sampling units determined using the SAC and conventional graphical method were 40 and 50, respectively. The first and second Cochran's sample size formula with an acceptable error rate of 10% required 78 to 92 plots, respectively. The range method suggested 53 to 160 plots, with an optimal number of 75. The CV method indicated that 10 plots had the lowest CV and were the most appropriate number of plots in the study area. The optimal sampling design was determined to be 75 plots, providing maximal information with minimal effort. Conclusion: The SAC method is suggested for determining sampling intensity in the desert ecosystems in this region due to its lower cost. The study revealed no significant relationship between the CV and the number of initial plots, and it is suggested not to use graphical methods or the CV method if the number of initial plots is less than 40. [ABSTRACT FROM AUTHOR]