Identification of priority areas for territorial space ecological restoration in arid area of Northwest China: A case study of Zhangye City in Heihe River basin.

Abstract

Determining priority areas for territorial ecological restoration in the arid region of Northwest China based on the holistic protection and systematic governance is an important measure to build solid national ecological security barrier and promote the construction of territorial ecological civilization. Taking Zhangye City, a typical arid area city in Northwest China, as an example, we constructed the research framework of "ecological network-ecological sensitivities-ecological degradation" from two aspects of internal defects and external threats of ecological networks by using circuit theory and assessment methods of ecological service function importance, ecological sensitivity, and ecological degradation. We then identified the priority areas of territorial ecological restoration in northwest arid region and put forward the restoration strategies. The results showed that the priority areas of ecological restoration in Zhangye City were concentrated in the artificial shelterbelt along rivers and the plain-desert-oasis transition zone with fragile ecology and strong human interference. The ecological network of the study area included 39 ecological sources and 99 ecological corridors, and the highly sensitive and degraded areas were 1595.40 and 6.65 km2. Based on the internal defects and external threats of the ecological network, we identified 31 ecological pinch points, 7 obstacle points, and 753.56 km2 ecological source areas in the territorial spatial ecological restoration priority area. These areas were related to the connectivity of the ecological network internally and the stability maintenance of the ecosystem outwards, and were the areas to restoration in the future. Following the concept of overall protection and system restoration of territorial space, we put forward the idea of territorial space restoration by integrating internal defects and external threats of ecological network, which could provide scientific decision-making basis for comprehensive ecosystem management and territorial optimization of Zhangye City.