What are the principal environmental filters driving species composition and succession on mineralogically different spoil heaps?

The relationship between selected environmental variables and plant species composition was studied on two mineralogically different spoil heaps (Hg and Cu) in Central Slovakia with contrasting reclamation approaches. Data on plant species composition were collected by stratified random sampling in defined physiognomic vegetation types. A detrended correspondence analysis showed that most of the variability in species composition was related to the succession gradient from open communities with a low cover of vascular plants to forest vegetation, and to the moisture gradient. Variance partitioning by canonical correspondence analysis revealed that most of the variability in plant composition was related to the content of various heavy metals (27.8% at the Hg-spoil heap and 28.3% at the Cu-spoil heap), but a significant relationship was found only for Mn. Other significant factors comprised soil moisture, pH and P content for the Hg-spoil heap and soil temperature and Ca content for the Cu-spoil heap. Although heavy metal content explained most of the variability in species composition, the relationship was caused by the correlation of heavy metal content with other environmental variables rather than by a direct causal relationship.

本研究以斯洛伐克中部两座矿物组成迥异、且采用截然不同修复方案的矿渣堆（汞矿渣堆与铜矿渣堆）为研究对象，探讨了所选环境变量与植物物种组成之间的关联。研究人员通过分层随机抽样法，在划定的外貌植被类型中采集了植物物种组成数据。去趋势对应分析（Detrended Correspondence Analysis）结果显示，物种组成的绝大多数变异与从维管植物盖度较低的裸露群落向森林植被过渡的演替梯度，以及水分梯度密切相关。通过典范对应分析（Canonical Correspondence Analysis）开展的方差分解结果表明，植物组成的大部分变异与多种重金属含量相关（汞矿渣堆中占比27.8%，铜矿渣堆中占比28.3%），但仅锰元素含量呈现出显著关联。其余显著影响因素包括：汞矿渣堆的土壤含水量、pH值与磷（P）含量，以及铜矿渣堆的土壤温度与钙（Ca）含量。尽管重金属含量解释了物种组成的大部分变异，但该关联实则由重金属含量与其他环境变量的相关性所驱动，而非直接的因果关系。