Assessment of desertification sensitivity using an improved MEDALUS model in Northern China

Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control. Based on the Mediterranean Desertification and Land Use (MEDALUS) model, we defined four quality indicators (soil, climate, vegetation and management) to evaluate the sensitivity of land in northern China to desertification. We improved MEDALUS via excluding cities from the areas at risk of desertification by means of defining a threshold value for population density. The framework, validated in northern China, further optimizes the model to link priority areas and land restoration programmed to support desertification control. We found that the four indicators influenced and restricted each other, which jointly affected the distribution of desertification sensitivity in northern China. The spatial distribution of sensitivity in northern China showed large regional differences, with clear boundaries and concentrated distributions of regions with high and low sensitivity; the overall sensitivity decreased, with some areas rated as having moderate, severe, and extremely severe sensitivity changing to slight sensitivity; and the influence weight was much higher for the management quality index than for the climate, vegetation, and soil indexes. This suggests that management was the main factor that affected desertification sensitivity in northern China, and that climate factors exacerbated sensitivity, but the factors that are driving the spatial heterogeneity of the influencing factors need further study.