Drought effects on vegetation degradation of Sistan

Nowadays، using GIS and satellite images has a special place in the studies of natural resources and environment. Comparison of the images of a specified time period can show the trends in each region. Sistan region in southeastern Iran has witnessed several periods of drought over the past century، and droughts between 1999 and 2006 are considered as the most severe drought over the past 600 years، having many environmental، economic and social impacts. In this study، vegetation changes in Sistan were examined by Weighted Difference Vegetation Index (WDVI) using Landsat TM images of 1998، corresponding to the time before drought and also ETM+ Images of 2002 during the drought. Results showed that the area of vegetation in Sistan reduced from 101 thousand hectares in 1998 to 24 thousand hectares in 2002، mainly due to the loss of arable land and removal of the cultivation. Vegetation restoration was limited to the areas such as Chah Nimeh، Niatak، Qurqory، and ungrazed rangelands of Lorge-bagh as man-made forests and protected areas.