A study of vegetation in Sistan region through satellite data

Desertification means land degradation in arid، semi-arid، and semi-humid areas، which happens due to changes in climatic conditions and human activities. Sistan plain is a dry area in the eastern part of Iran that is suffering from desertification as the main problem. The main purpose of this two-year study is to assess changes in the vegetation of the region within the time period from1990 to 2006. Field sampling، satellite images، and related software were used to conduct the present study. First of all، field sampling method was randomly and systematically performed in 26 wellknown sites. For each site، nine 10×10 m plots were recorded. In the next stage، the required processes were conducted on the satellite images and vegetation indices were generated. Correlation analysis was performed between data related to land coverings and spectral values of corresponding pixels. The highest correlations obtained among 83 estimated indicators were related to indices of WDVI، NDVIab، TSAVI2 and MSAVI1، respectively. The obtained images were classified into two coverage and non-coverage groups. Then the precision of plots were evaluated and the highest precision of 83. 27% was related to the plot taken for WDVI which had the highest correlation coefficient (p<0. 01 and R2 =0. 89) as well. Based on these plots، vegetation rate was determined as 101247 acre for 1990 which decreased to 26475 acres for 2006.