Sensitive area identification and hierarchical protection in the western Anhui ecological barrier zone from the coupling perspective of landscape ecological risk and vegetation coverage

Objectives This study aims to systematically evaluate the spatial pattern of landscape ecological risk in the western Anhui ecological barrier zone, reveal its coupling coordination relationship with fractional vegetation cover (FVC), and identifies key sensitive zones for graded conservation, thereby providing quantitative evidence for regional ecological conservation and restoration.

Methods Based on normalized difference vegetation index (NDVI) and land-use datasets for years 2000 and 2022, a regular grid evaluation unit was established. An integrated framework incorporating disturbance degree and vulnerability was applied to quantify the landscape ecological risk index (ERI) and identify ecologically sensitive zones. Building on this, using FVC as a proxy indicator of ecological condition, a coupling–coordination model (D) was constructed to analyze the synergistic evolution characteristics of the “risk-state” dual system.

Results 1) The ERI exhibited an overall spatial pattern of “higher in the north and south, lower in the central region”. From 2000 to 2022, areas classified as medium- and high-risk zones significantly contracted and shifted toward low risk, resulting in the identification of approximately 6 572.17 km² of ecologically sensitive zones. 2) Within these sensitive zones, the FVC was predominantly high, yet exhibited an overall declining trend. The mean NDVI decreased from 0.883 to 0.823, and regions with low-cover expanded notably, primarily distributed along the northern boundary and localized southern areas. 3) The overall coupling coordination degree (D) declined, with the proportion of “high-quality coordination” areas dropping from 95.25% to 83.67%, while the extents of mild, moderate, and severe discoordination expanded. Through comprehensive identification, a total of 1 073.50 km² were delineated as priority management areas, comprising 872.94 km² designated for general protection and 200.56 km² for key protection.

Conclusions Although the overall ecological risk in the western Anhui ecological barrier zone showed a decreasing trend, vegetation degradation within sensitive zones has weakened the coordination of the “risk-state” system. We recommend that the identified 1 073.50 km² critical area be subjected to hierarchical protection and refined ecological restoration measures to support the stable establishment of a regional ecological security pattern.