Mason T J, Krogh M, Popovic G C, Glamore W, Keith D A
Centre for Ecosystem Science, UNSW Sydney, Australia; New South Wales Department of Planning, Industry and Environment, Australia.
New South Wales Department of Planning, Industry and Environment, Australia.
Sci Total Environ. 2021 Jun 10;772:144772. doi: 10.1016/j.scitotenv.2020.144772. Epub 2021 Jan 26.
More than half of global wetlands have been lost because of anthropogenic disturbance, with the trend of decline continuing in the 21st century. While much of this loss relates to changes in surface flows, groundwater is also critical to sustaining wetland hydrology. Underground longwall mines extract coal seams, in turn fracturing the overlying stratigraphy, influencing aquifer connectivity and affecting surface flows via subsidence disturbance. Crucially, this subterranean disturbance may disrupt the hydrological processes that sustain freshwater wetlands at the surface. Here we present a new designed empirical study that compares the persistence of soil moisture after a rainfall event in wetlands subject to underground longwall coal mining to that in unmined reference wetlands. Accelerated Failure Time models showed that mined wetlands were persistently drier, retained water for shorter durations and exhibited less spatial differentiation than unmined wetlands. This quantitative evidence of severe, persistent hydrological change following resource extraction reinforces earlier observations and has important implications for biodiversity and provision of ecosystem services to a large urban population. If Ecologically Sustainable Development (ESD) outcomes and effective deployment of the mitigation hierarchy are to be achieved in line with current legislative and policy paradigms, our results highlight the need for more emphasis on impact avoidance and minimisation than restoration or offsetting to protect water and biodiversity values. Given severe constraints on restoration success, greater emphasis on avoidance in mine design and approval processes offers realistic opportunities for an improved balance between sustaining irreplaceable public assets and short-term benefits from non-renewable resource extraction.
由于人为干扰，全球一半以上的湿地已经消失，且在21世纪这种减少的趋势仍在持续。虽然这种损失大多与地表水流变化有关，但地下水对于维持湿地水文也至关重要。地下长壁式煤矿开采煤层，进而使上覆地层破裂，影响含水层连通性，并通过沉降干扰影响地表水流。至关重要的是，这种地下干扰可能会扰乱维持地表淡水湿地的水文过程。在此，我们开展了一项新设计的实证研究，比较了受地下长壁式煤矿开采影响的湿地与未开采的对照湿地在降雨事件后土壤湿度的持续性。加速失效时间模型表明，与未开采的湿地相比，开采后的湿地持续更干燥，保水时间更短，且空间差异更小。这种资源开采后严重、持续的水文变化的定量证据强化了早期观察结果，对于生物多样性以及向大量城市人口提供生态系统服务具有重要意义。如果要根据当前的立法和政策范式实现生态可持续发展（ESD）成果并有效运用缓解层级体系，我们的研究结果凸显了相较于恢复或补偿，更需强调避免和最小化影响以保护水资源和生物多样性价值的必要性。鉴于恢复成功面临严重限制，在矿山设计和审批过程中更加强调避免影响，为在维持不可替代的公共资产与不可再生资源开采的短期利益之间实现更好平衡提供了切实可行的机会。
