Construction of an ecological security pattern in Wu'an City, Hebei Province based on ecosystem service supply-demand and sensitivity.

To address ecological security issues such as the imbalance between supply and demand of regional ecosystem services as well as severe soil erosion, constructing a scientific ecological security pattern has become a core issue in territorial spatial governance. Wu'an City in Hebei Province is a key national-level soil erosion control area in the Taihang Mountains. We identified initial ecological source areas with high levels of ecosystem service supply in Wu'an by using the InVEST model and ecosystem service supply-demand ratio assessment method. Combined with soil erosion analysis, we assessed areas with high soil erosion sensitivity but intact ecological structures as potential ecological source areas. Based on the spatial distribution characteristics of these two types of ecological source areas, we conducted a comprehensive overlay analysis to construct a regional ecological resistance surface. The minimum cumulative resistance model and circuit theory methods were used to identify key ecological corridors, ecological pinch points, and ecological barriers, thereby constructing an ecological security pattern framework suitable for key soil erosion control areas. The results showed that a total of 49 ecological source areas (with a total area of 752.16 km2, accounting for 41.4% of the study area), 98 ecological corridors (with a total length of 421.45 km), 18 ecological pinch points, and 6 ecological barriers were identified. We found a "four-axis multi-zone" ecological restoration pattern, forming a three-level spatial governance system of "protected areas-corridors-restoration areas" that was aligned with territorial spatial planning, enhancing the scientificity and applicability of the ecological security pattern in soil erosion control areas. By coupling ecosystem service supply and demand with soil erosion sensitivity, this study expanded and improved traditional methods for identifying ecological source areas, improving the pertinence to soil erosion issues.