Evaluation of vegetation changes in desertification projects using RS-GIS techniques

The earth landscape is always changing due to human activities and natural phenomena. Therefore, in order to optimize the management of the natural areas, knowledge of the trend and extent of land cover / land use changes is considered necessary, and the estimation of these changes is of great importance. Reviewing these changes through satellite images and predicting and evaluating their potential through modeling can help environmental planners and natural resource managers to make more informed decisions. In the present study, quantitative detection and evaluation of changes in vegetation was performed in the areas with combat desertification projects, Shahdad and Bam in Kerman province and Garmsar in Semnan province, during a 30-year period within 1987, 2002 and 2017. The NDVI vegetation index and land use maps were produced using the ETM + TM and OLI satellite images in the three corresponding periods for the vegetation lands/non-vegetation lands, and agricultural lands. The Kappa coefficient of 0.83 to 0.86, 0.91 to 0.92, and 0.94 to 0.95 was calculated for 1987, 2002, and 2017, respectively, and the total accuracy was between 88 % and 97 %. After providing the land use maps in different years, the monitoring of land use changes was investigated using the change detection methods. According to the trend of changes during the studied periods, our results showed that the vegetation lands in these three areas had an increasing trend, and the non-vegetation lands were turned to vegetation lands over time. Moreover, an increasing trend was found for the agricultural lands during these three periods. Finally, the cost-effectiveness of projects implemented in the studied areas was calculated and evaluated.