Identification of priority areas for ecological restoration based on ecological security and landscape elements

Accurate identification of priority areas for ecological restoration is an important prerequisite for ecological protection and restoration, but it is a current challenge in landscape planning. Northern Shaanxi, which is located in the middle of the Loess Plateau in China, was selected as a study area in this paper. A three-dimensional framework including natural potential, human disturbance, and landscape pattern factors was used to construct an ecological security evaluation index system, and spatial principal component analysis (SPCA) was used to quantitatively evaluate the ecological security levels of the study area. The ecological security assessment result was used as a resistance surface, and landscape elements were identified by morphological spatial pattern analysis (MSPA), minimum cumulative resistance (MCR) model and the gravity model. On this basis, priority areas for ecological restoration were identified by considering ecosystem security and the matching degree of landscape elements. The resulting area with low and moderately low security levels was 27,574.87 -km(2) in size, accounting for 34.48% of the total study area, and the ecological security situation was not ideal. We identified seventeen ecological sources with an area of 5789.36 -km(2), and the important ecological sources were mainly distributed in the south of the study area. We identified one hundred and thirty-six potential ecological corridors with a total length of 7431.12 km, including 16 important ecological corridors with a length of 1279.43 km. We also identified 83 ecological nodes, including 17 important ecological nodes. We found that the high matching degree of landscape elements included four watersheds with an area of 7571.17 -km(2), mainly distributed in the southern part of the study area. Fifty-one basins with a low matching degree of landscape elements were identified, covering an area of 50,399.44 -km2 and mainly distributed in the west and north of the study area. We identified three levels of areas to be restored, of which the level I ecological restoration priority area was the smallest, at 7047.61 -km(2). The areas of the level II ecological restoration priority area and the level III ecological restoration priority area were 20,379.35 -km(2) and 27,866.35 -km(2), respectively. The two areas were large and mainly distributed in the west and north of the study area. We discussed ecological restoration strategies for different levels of ecological restoration priority areas and provided new methods for identifying priority ecological restoration areas in the future.