黄土高原露天煤矿复垦土壤−植被系统恢复力及协同/权衡关系

Resilience and synergy/trade-off relationship of soil-vegetation system in dump reclamation of surface coal mines on the Loess Plateau

  • 摘要: 土壤−植被互作互馈推动受损矿山生态系统修复趋向良性循环,但目前对露天煤矿区植被恢复与土壤功能之间关联和互馈机制认识尚浅,限制了矿区植被恢复策略的科学制定。选取黄土高原黑岱沟露天煤矿4个不同时序排土场复垦区,利用野外调查、高通量测序和恢复力评估模型等方法,构建草地、灌木、针叶林、阔叶林和混交林等5类系统恢复力评估模型来探索生态恢复下土壤−植被系统功能之间权衡/协同关系。结果表明:① 与未复垦裸地相比,复垦8~30 a土壤各项指标恢复介于30%~80%,植被各项指标恢复介于20%~75%;② 第15 a时草地和灌木土壤养分保育和生态碳汇的功能恢复速率达峰值,针叶林、阔叶林和混交林则第25 a时达峰值。土壤系统恢复水平为混交林>草地>针叶林>阔叶林>灌木,植被系统恢复水平为混交林>阔叶林>针叶林>草地>灌木。③ 草地、灌木和阔叶林与其土壤系统功能恢复力以权衡关系为主,针叶林和混交林则以协同关系为主。黄土高原露天煤矿区植被恢复显著改善了复垦土壤物理、化学、生物性状和群落特征,复垦年限对土壤−植被系统功能恢复水平和速率有着显著地影响。随复垦年限延长,各功能恢复力之间呈现此消彼长的权衡关系。研究揭示了复垦土壤−植被系统恢复力具有强时序性,为黄土高原露天矿区生态恢复过程中适时调配植被建群策略,促进土壤−植物系统功能协同发展,科学制定和优化生态修复方案提供理论依据。

     

    Abstract: The interaction and feedback between soil and vegetation will promote the restoration of damaged mine ecosystems towards a virtuous cycle, especially in surface mine dump site reclamation areas. However, the lack of understanding of the correlation and mutual feedback mechanism between vegetation restoration and soil functions limits the scientific formulation of vegetation reconstruction strategies for surface mine dump sites. This study aims to reveal the trade-off and synergistic relationship between vegetation succession and soil system functions during the vegetation restoration process. Using methods such as field surveys, high-throughput sequencing, and resilience assessment models, four reclamation areas with different reclamation timings were selected in the Heidaigou surface coal mine on the Loess Plateau, and a resilience assessment model and trade-off synergy were constructed for five plant restoration types: grassland, shrub, coniferous forest, broad-leaved forest and mixed forest. The results show that: (1) compared with bare land, the recovery degree of soil indicators is 30~80% and the vegetation index recovery degree is 20~75% after 8~30 a of restoration. (2) The recovery rate of soil nutrient conservation and ecological carbon sink functions of grassland and shrubs peaked at 15 a, and the recovery rate of coniferous forest, broadleaf forest and mixed forest peaked at 25 a. The recovery degree of the soil system is mixed forest > grassland > coniferous forest > broadleaf forest > shrubs, and the vegetation system recovery is mixed forest > broadleaf forest > coniferous forest > grassland > shrubs. (3) In terms of the overall trend, the functional resilience of grassland, shrub and broad-leaved forest vegetation and soil systems is mainly in a trade-off relationship, while coniferous forest and mixed forest are mainly in a synergistic relationship. It concludes that the vegetation restoration significantly improves the physical, chemical, biological properties and vegetation community characteristics of the reclaimed soil, the reclamation years significantly affects the recovery elasticity and rate of the soil-vegetation system in the surface mine area of the Loess Plateau, China. As the reclamation years increase, there is a trade-off relationship between soil-vegetation system indicators. The research results confirm that different vegetation types have temporal characteristics in improving the resilience of the soil-vegetation system. Therefore, it is recommended to appropriately adjust the vegetation clustering strategy, allocate vegetation types in a timely manner, and fully coordinate the relationship between various soil functions to optimize the surface mine ecology of the Loess Plateau. The study provides a scientific basis for the restoration planning and management of disturbed surface mine.

     

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