Desertification is the consequence of a set of important degradation processes in the Mediterranean environments, especially in semi-arid and arid regions, where water is the main limiting factor of land use performance on ecosystems. Environmentally Sensitive Areas (ESAs) to desertification around the Mediterranean region exhibit different sensitivity to desertification for various reasons.

For example there are areas presenting high sensitivity to low rainfall and extreme events due to low vegetation cover, low resistance of vegetation to drought, steep slopes, highly erodible parent materials, etc. High sensitivity can be also related to the type of land use for the cases that it promotes desertification in climatically and topographically marginal areas. For example cereals cultivated in hilly areas with soils formed on marl present a serious threat for desertification. Furthermore, there are areas which are sensitive to desertification for special reasons, such as fire risk, which is likely to generate runoff and erosion problems for some years; rambla and flood plain environments, where fluctuating phreatic levels may show salinization and toxicity problems; and exotic tree plantations, where poor ground cover and autotoxicity may lead to higher runoff and sediment yields.

The various types of ESAs to desertification can be distinguished and mapped by using certain key indicators for assessing the land capability to withstand further degradation, or the land suitability for supporting specific types of land use. The key indicators for defining ESAs to desertification, which can be used at regional or national level, can be divided into four broad categories defining the qualities of soil, climate, vegetation, and management (stressor indicators). This approach includes parameters which can be easily found in existing soil, vegetation, and climate reports.