Study on ecological degradation characteristics and carbon sink enhancement pathways in abandoned mines in cold regions: a case study of Heilongjiang Province

This study aims to systematically analyze the ecological degradation characteristics of abandoned mines in the cold region of Heilongjiang Province and their impact on regional carbon sink function and explore ecological restoration pathways for enhancing the carbon sink capacity of mining areas. A comprehensive assessment was conducted on vegetation coverage, soil’s physicochemical properties, and microbial diversity in abandoned mine areas through field surveys, soil sampling, and microbial community sequencing. The results indicate that abandoned mines commonly exhibit significantly reduced organic carbon content in soil, severe structural damage, and low microbial activity. The microbial community structure shows marked changes, and the degree of vegetation restoration is significantly positively correlated with the soil’s carbon storage. Based on the concepts of community function construction and carbon cycle enhancement, a comprehensive restoration strategy centered on vegetation reconstruction, soil improvement, and microbial function optimization is proposed. For vegetation reconstruction, plants with strong adaptability, stress resistance, and carbon sequestration potential, such as Populus davidiana, Pinus sylvestris var. mongolica, Hippophae rhamnoides, Amorpha fruticosa, Iris lactea, and Medicago sativa, are selected to construct multi-layered and multifunctional community structures to enhance ecosystem stability and carbon sink sustainability. For soil improvement, amendments such as humic acid, organic fertilizer, and biochar are applied to enhance soil structure and aggregate formation, promoting carbon input and stable sequestration. For microbial function optimization, arbuscular mycorrhizal fungi and functional bacteria are introduced to activate the “plant, microorganism, and soil” carbon cycle system, facilitating efficient carbon transformation and storage. This integrated strategy can effectively enhance the carbon sink function of mining ecosystems in cold regions, providing a scientific basis and technical support for ecological restoration of abandoned mines and regional carbon neutrality goals.