Evaluation of Ecological Sensitivity and Its Topographic Gradient Characteristics in Qinling-Bashan Mountains

[Objective] Qinling-Bashan mountains are not only an important ecological function area, but also a concentrated contiguous poverty-stricken area in China. It is of great practical significance to strengthen the ecological sensitivity evaluation and reveal the terrain gradient characteristics for the delineation of ecological red line and the construction of regional ecological highlands in the mountainous area. [Methods] Based on the data of land use / cover, climate, terrain and soil type, the linear weighted sum method, entropy weight method and spatial overlay analysis method have been used to evaluate its ecological sensitivity, and the sensitive function zoning and ecological protection countermeasures have been put forward. [Results] (1) The ecological sensitivity fluctuated in Qinling-Bashan mountains during 2000—2018 and it decreased after 2010;(2) Horizontally, the ecological sensitivity of Bashan mountains is higher than that of Qinling mountains; (3) Vertically, with the increase of terrain, it shows the trend of“first increasing-decreasing-then increasing”. The ecological sensitivity is the highest around 900 m of elevation, and the distribution area of ecological sensitivity above severe degree is the most extensive in 75 ~ 200 m of surface cutting depth and 15° ~ 25° of slope.(4) According to the evaluation results, it is divided into five types: key construction area, moderate development area, soil-and-water conservation area, general ecological area and important ecological area, and their characteristics and protection countermeasures have been summed up and put forward. [Conclusion] In the future, we should continually optimize the land use pattern, strengthen the comprehensive management and ecological restoration of mountains, forest, farmlands, lakes and grasslands.