干旱区生态环境知识资源中心

The environmentally sensitive areas (ESAs) model has been applied to evaluate the risk of desertification in the Chehel-Chai Watershed, northern Iran. This research is mainly conducted to quantify and assess the effect of land-use change processes on desertification risk in areas with humid climate. Water erosion, soil, vegetation, climate and management practices were used as five main criteria for desertification mapping in this study. The degree of sensitivity to desertification was determined for each land unit using the categorization table of desertification intensity. For providing insights into optimal management programs, the desertification sensitivity map was used to analyze different scenarios of management strategies. By assuming that other indices are constant, these scenarios were replaced by altering land-use intensity parameter. Based on five above-mentioned criteria, the mean weight of quantitative value for desertification sensitivity was calculated, which was 1.32 for the research location. By comparing this value to ESAs table, the desertification class of the study area was determined as fragile (type 2). Scenario analysis results indicated that the relative frequencies of areas with critical states of desertification (i.e., classes 1, 2 and 3) are reduced by 18.84 and 14.27% in vegetation management scenario and land ecological capability evaluation scenario, respectively. Results of this study also highlighted that scenario maps are efficient tools for analyzing and identifying areas at high risk of desertification in Chehel-Chai Watershed, where desertification process could be alleviated if appropriate land-use planning and vegetation management programs are adopted.