Ecological Restoration Techniques for High and Steep Rocky Slopes—Reconstruction of the Underground Habitat

Mining and transportation development have resulted in numerous high and steep rocky slopes, posing significant geological safety hazards and causing ecological and environmental problems. Vegetation restoration is a key part of ecological restoration on high and steep slopes. However, existing related technologies generally suffer from insufficient theoretical support, long maintenance cycles, and limited applicability. This study investigates temperature and humidity conditions of high and steep rocky slopes in a quarry in Jinan, Shandong. Based on the findings, optimized planting holes parameters were proposed to reconstruct subsurface habitats and enhance plant use of slope fractures for water and nutrient uptake. The feasibility of this method is evaluated through on-site revegetation trials and long-term monitoring of plant growth. The research results indicate that plant roots are mainly distributed in the 0-40 cm soil layer, and the temperature and humidity conditions at different depths within the slope are generally suitable for plant growth. The optimized planting hole parameters are a depth of 50 cm, a diameter of 15 cm, an angle of 45°, and horizontal and vertical spacing of 1 m. Planting holes should be prioritized in fracture-developed zones and filled with soil substrate. Drought-tolerant species should be selected for reforestation trials, encouraging plants to establish roots in fractures and grow naturally. Five years later, the plant survival rate reached 76.92%, and vegetation cover increased to 54.03%. Growth indicators such as plant height, crown width, and base diameter showed rapid increases. These indicators remained stable during dry season without additional maintenance. The above results indicate that the method of revegetation of steep rocky slopes based on the reconstruction of underground habitats is feasible in terms of improving plant survival rates and stability. This study enriches the theoretical framework for ecological restoration of steep rocky slopes and deepens the understanding of plant-fracture interactions, offering both significant theoretical and practical value.