Vegetation Vulnerability Probability Index: A Method for Determining Desertification Risk

Subject Areas : Agriculture, rangeland, watershed and forestry

Esmail Heydari Alamdarloo ¹ , Pouyan Dehghan Rahimabadi ² , Hassan Khosravi ³ , Javad Rafie Sharifabad ⁴ , Hassan Barabadi ⁵

1 - Postdoc, Department of Reclamation of Arid and Mountainous Regions, Faculty of Natural Resources, University of Tehran, Iran
2 - Ph.D. in Combat to Desertification, Department of Reclamation of Arid and Mountainous Regions, Faculty of Natural Resources, University of Tehran, Iran
3 - Associate Professor Department of Arid and Mountainous Regions Reclamation, Faculty of Natural Resources, University of Tehran, Iran
4 - Ph.D. in Combat to Desertification, Faculty of Natural Resources, University of Hormozgan, Iran
5 - Ph.D. in Combat to Desertification, Faculty of Natural Resources, University of Kashan, Iran

Received: 2022-03-18 Accepted : 2022-07-19 Published : 2024-06-26

Keywords: Vegetation cover, Yazd, Desertification, remote sensing,

Abstract :

Determining desertification risk can be a good way to prioritize an area for management and control of the desertification process. One determinant of desertification risk is the use of the Probability of Vegetation Vulnerability Index (PVVI). For this purpose, in this study, LST and EVI of MOD11A2 and MOD13A2 products, respectively, from MODIS sensors were used to calculate TCI and VCI to estimate VHI in Yazd province from 2001 to 2019. VHI, which indicates the severity of drought, was classified into five classes. Then, the probability of occurrence for each class was calculated and multiplied by the weight of each class, which was between zero and 4 based on the severity of the drought. Finally, by adding the values obtained for each class, PVVI was calculated. The results showed that in the western, eastern, and southern parts of Yazd province, the risk of vegetation degradation and consequent desertification is generally higher than in other areas. The highest probability of Non-drought class occurs in Abarkooh (VHI = 68.34) and the lowest is in Ardakan (VHI = 53.59). Abarkooh with 14.03% and Ardakan with 46.02% have the lowest and the highest areas in the high class of PVVI. Also desert areas and uncovered lands, such as Abarkuh, were at low risk of desertification, which could be due to the ecological inability of this area to regenerate the vegetation cover. In general, the evaluation of the results obtained in this study showed that PVVI can distinguish real deserts from the areas that are at risk of desertification.