Plant interactions with oxygen barrier covers used to reclaim mine waste storage areas: a functional ecology approach.

在潮湿的气候条件下，氧气屏障覆盖物的功能依赖于几乎水饱和的部分，通过该部分氧气扩散到下面的活性废物是有限的（具有毛细屏障效应的覆盖物CCBE，具有升高的地下水位EWT的覆盖物）。氧气屏障（OB）覆盖物可能会迅速被来自邻近生态系统的植物定殖。植物对OB覆盖功能（即覆盖水文地质特性）的影响评估不准确，可能导致覆盖无法实现其使命，并以环境污染为代价。植物对覆盖功能的贡献的预测往往是不准确的。首先，一个主要的缺陷是忽略了根的生长作为一个动态的过程，影响水的运动在封面。第二，需要进行专注于挖掘上下文的实验来改进预测。因此，长期目标是将植被驱动的生态系统过程整合到OB覆盖中，以改善其长期性能的预测。该研究将使用现场规模和受控实验室监测，并依赖于明确的定量实验方法。基于植物特性的功能生态学方法将允许研究植物对OB覆盖水文地质特性的影响，并将其与环境变化（即非生物过滤器）联系起来。将解决三个短期目标：1）测量植物根系对OB覆盖功能和完整性的影响。本文通过田间试验，研究了植物根系性状与土壤饱和导水率（ksat）和土壤水分保持层孔隙度（MRL）之间的关系。树木连根拔起和相关的侵蚀风险将与根特性在原位类似物的覆盖EWT的尾矿; 2）预测控制非生物因素对根特性的影响CCBE功能。繁殖CCBE的中生态系统将种植北方木本物种，并提交水和养分胁迫，以精确控制根系对覆盖功能的影响的环境变化的理想范围; 3）研究表土发育对非生物胁迫暴露和OB覆盖功能减少的贡献。表层土或有机物的存在对顶部的覆盖的影响将涉及到土壤和木本物种的水的关系，营养，和根的性状在繁殖的CCBE和单层尾矿覆盖EWT的中生态系统。* 这些成果将构成一个知识基础，供应用于其他废物封隔技术，并可能导致生态工程发展，以控制植物对覆盖物水文地质特性的影响。三名HQP将获得跨学科的技能，并能够设计出满足工业，政府和社区需求的回收技术。

Under humid climates, the functioning of oxygen barrier covers relies on a nearly water-saturated part through which oxygen diffusion to the underlying reactive wastes is limited (covers with capillary barrier effect CCBE, covers with elevated water table EWT). Oxygen barrier (OB) covers may rapidly be colonized by plants coming from adjacent ecosystems. Inaccurate evaluation of plant effects on OB cover functioning, ie cover hydrogeological properties, can result in cover failure to achieve its mission, at the cost of environmental pollution. The prediction of plant contribution to cover functioning is often inaccurate. First, a major deficiency is the omission of root growth as a dynamic process that affects the movement of water in the cover. Second, experiments focused on the mining context are needed to improve the predictions. Thus, long-term objective is to integrate vegetation driven ecosystem processes to OB covers functioning to improve the prediction of their performance at the long-term. The research will both use field-scale and controlled laboratory monitoring and rely on a clear quantitative, experimental approach. A functional ecology approach grounded on plant traits will allow to study plant effects on OB cover hydrogeological properties, and relate them to environmental variations, ie abiotic filters.***Three shorter-term objectives will be addressed: 1) Measure plant root effects on OB cover functioning and integrity. The relation between plant root traits, saturated hydraulic conductivity (ksat) and porosity of the moisture retaining layer (MRL) of a CCBE will be studied in situ. Tree uprooting and associated erosion risk will be related to root traits on in situ analogues of covers with EWT made of tailings; 2) Predict the control of abiotic factors on root traits that impact CCBE functioning. Mesocosms reproducing a CCBE will be planted with boreal woody species and submitted to water and nutrient stress to precise the desired range of environmental variations that control root effects on cover functioning; 3) Study the contribution of topsoil development to the decrease of abiotic stress exposure and OB cover functioning. The effect of topsoil or organic matter presence on the top of the cover will be related to soil and woody species water relations, nutrition, and root traits in mesocosms reproducing a CCBE and a monolayer tailings cover with EWT. ***The outcomes will constitute a knowledge base for application to other waste confinement technologies and could result in eco-engineering developments to control plant effects on cover hydrogeological properties. Three HQP will acquire interdisciplinary skills and will be able to design reclamation technologies responding to industrial, government, and communities' needs.**