Revised zoning method for environmental fragility evaluation to desertification in arid–semiarid areas: a case of Dousitu river basin

The eco-environmental problems caused by land desertification are becoming the main restricting factors in regional development. In this study, the engineering eco-environment patterns (EEPs) are proposed to evaluate the eco-geological environment fragility to desertification in arid and semiarid areas. A revised zoning method in the variable-weight theory (VWT) was used for EEPs and applied in the Dousitu River Basin (DBR). First, the EEP mechanism was elucidated, of which four types were divided. Second, ten key controlling indicators from climatology, geography, vegetation and social conditions were collected, of which the thematic maps were imported. Third, the weight and its interval of the indicator were determined, establishing the partial stimulation-punishment variable-weight zoning model. Finally, the evaluation result was obtained and mapped in four models or zones. Furthermore, the evaluation via the CWT method was also completed for comparison. Both results from VWT and CWT were validated with the ecological groundwater level (EGL) theory, which proved the accuracy of the VWT study. The method helps with the rational plan and design for the regional economic development and protection of eco-geological environment.