Construction of ecological security pattern in Loess Plateau counties by integrating structural connectivity and functional enhancement: A case study of Ansai District, Yan'an City, Northwest China.

Ecological security pattern is an important spatial way to maintain ecological processes and ensure the stability of ecosystem functions. As the implementation of landscape planning and decision-making, it is critically needed to consider the consistency of differentiated methods and their spatial outputs in the construction of ecological security patterns and the matching and applicability of research objects. From the perspective of integration, we combined the regional topography and landscape characteristics, integrated the morphological spatial pattern analysis and the importance evaluation results of ecosystem services to identify the ecological source, and constructed the ecological security pattern of the Ansai District of Yan'an City, the main implementation area of the Grain-for-Green Project on the Loess Plateau. The results showed that the structural and functional construction methods had low consistency in the identification of spatial protection priority. The integration-oriented method could complement each other and achieve the dual goals of structural connectivity and functional improvement. There were 202 ecological sources in the study area, with a total area of 391.58 km², accounting for 13.3% of the total area of the study area. There were 110 ecological corridors in the study area, with a total length of 599 km, which were mainly distributed around the river channel, showing a distribution pattern of 'short and narrow dense in the north and south, long and wide in the middle'. The structure-function integration method provides new insights for ecological restoration planning of land space and promotes the research of landscape pattern, process and service.