Damage mechanisms of small-to-medium-scale mines on ecological networks at watershed scale and systematic nature-based mine restoration pathways

Abstract

The major challenge of mine ecological restoration that adheres to the systems concept is how to achieve holism and systematics. From an ecological security pattern perspective, understanding how small-to-medium-scale mines (SMMs) impact the ecological network at the watershed scale is critical for prioritizing restoration efforts and specific restoration pathways, which is conducive to achieving holistic protection, systematic restoration, and comprehensive management. Choosing a typical SMMs clustered watershed in northwestern Liaoning Province, this study employed morphological spatial pattern analysis (MSPA) to construct the ecological network. By analyzing the dynamic evolution of the ecological network from 1989 to 2022 and combining it with the mine development characteristics, the damage mechanisms of SMMs to the ecosystem structure were identified. Using graph theory and Conefor software, restoration priority areas and corresponding restoration pathways were identified through an evaluation of the ecological connectivity importance of mines. Results indicated significant declines in ecological sources and corridors from 1989 to 2022, with decreasing α, β, γ indices reflecting weakened connectivity and stability of the ecological network. Single small-scale mines without clusters directly destroy only a portion of ecological sources at the periphery of the mining center (usually 2–4 times the size of the mine). Large-scale clustered SMMs indirectly cause the disappearance of ecological sources and corridors connecting those sources altogether through their impact on landscape patterns. Systematic restoration of SMMs should follow nature-based solutions (NbS), which can be used to comprehensively determine restoration pathways based on the ecological status and damage mechanisms of each mine, including natural regeneration, assisted regeneration, and guided artificial reconstruction. Especially for large-scale clustered SMMs, all mines should be planned and restored uniformly to integrate with the surrounding natural ecosystems and enhance the stability of the ecological network. This systematic approach we propose is more holistic and systematic than individual reclamation projects and is an effective practice for NbS.