Monitoring of spatio-temporal indices on desertification in arid regions of south of Khorasan Razavi province

Desertification is one of the most complex environmental threats with negative effects on the socioeconomic that play an increasing role in the severity of land degradation over the times. This study was carried out to monitoring the spatiotemporal variability of the criteria and indices effective on desertification in an arid region in the south of Khorasan Razavi province. Primary data, such as climatic parameters, vegetation, geology, soil, groundwater and surface water, agriculture and socioeconomic data were collected and introduced into the GIS environment, and a geobiofacies unit map was prepared. Then, desertification intensity was calculated by using the Iranian Model for Desertification Potential Assessment (IMDPA). Evaluations of indices were done based on available data and maps, expert opinions and satellite imagery in a GIS environment. The results showed the desertification severity being in two classes of medium and severe with 77% and 22%, respectively. Periodic monitoring of the effective indices on desertification also showed that low precipitation over the past 25 years 1984-2009 has caused increasing drylands and droughts. Assessment of land use changes during 10 years 2001-2011 indicated decreasing 6% in rangelands and an increase in agriculture, which was mainly due to 1.5% population growth rate during the years 1986 to 2011. The excessive removal of groundwater aquifers also caused a 10% drop in the wells water levels, resulting in increased land salinity as well as an increase in wind erosion in more than 93% of the study area.