Abstract:

Ecological sensitivity is a critical indicator for evaluating the response and self-regulation capacity of ecosystems under external disturbances. It plays an essential role in ecological redline delineation， spatial planning， and the construction of regional ecological security patterns. This study takes Qingyang City， a typical gully region on the Loess Plateau， as the research area. Based on multi-period remote sensing and land use data from 2000 to 2020， four key ecological indicators—elevation， aspect， NDVI， and land use type—were selected to build an ecological sensitivity evaluation system. The Analytic Hierarchy Process （AHP） was employed to determine index weights， and GIS-based overlay analysis was used to map spatial distribution patterns of ecological sensitivity and explore their coupling mechanisms with land use and vegetation cover changes. The results show that： （1） Land use in Qingyang has significantly improved over the past two decades， with continuous expansion of forest and grassland and a notable reduction in unused land.（2） NDVI exhibited a trend of “low values increasing and high values remaining stable，” indicating significant vegetation restoration driven by ecological projects.（3） Ecological sensitivity displayed clear spatial differentiation， with lower sensitivity in the northwest and central areas and higher sensitivity in the southeast. Medium and high sensitivity zones dominated the region， while highly sensitive zones were mainly distributed in key ecological barrier areas such as the Ziwuling forest and the headwaters of the Jing River. This study provides a practical and replicable approach for ecological sensitivity evaluation in loess hill and gully regions， offering scientific support for ecological zoning， land management， and environmental policy development.

Key words: ecological sensitivity, Loess Plateau, land use change, NDVI, GIS, AHP