Dynamic optimization of the ecological red line in Zhejiang Province based on wilderness protection

Human activities continuously encroach upon wilderness spaces, which is a severe threat to biodiversity. The ecological red line (ECR), which was innovatively demarcated and strictly executed in China, has played a great role in the construction of ecological civilization and the protection of ecological environment. However, the concept of wilderness was originated late, and thus the protection of wilderness was hardly considered when ECR was defined before. Based on an improved wilderness identification model, we overlaid and analyzed wilderness areas with existing ECRs to evaluate the ECR's contribution to wilderness protection in Zhejiang Province. Taking the balance and spatial distribution difference between economic and ecological benefits of wilderness into consideration, we put forward the potential optimization path of current ECR. The results showed that, during 2010-2020, the distribution pattern of wilderness land in Zhejiang Province was "more in the west and less in the east". The area of wilderness land decreased by 20.8%, and the overall quality of wilderness land showed an obvious downward trend. During the study period, the loss of wilderness land within the red line was less, and the quality of 27.2% of wilderness land was improved, while the loss of wilderness land outside the red line was serious and the overall quality decreased. The current ECR only covered 29.8% of wilderness, indicating significant protection gaps. Integration and optimization of the ECR resulted in a 40.2% increase in ECR area and a 135.8% increase in protected wilderness area. Our results could provide a theoretical basis for improving the efficiency of ECR protection, formulating key wilderness protection ways, and promoting the sustainable development of cities and towns and the maintenance of biodiversity.