Rowland S M, Prescott C E, Grayston S J, Quideau S A, Bradfield G E
Dep. of Forest Sciences, Univ. of British Columbia, 3041-2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.
J Environ Qual. 2009 Jun 23;38(4):1580-90. doi: 10.2134/jeq2008.0317. Print 2009 Jul-Aug.
During oil-sands mining all vegetation, soil, overburden, and oil sand is removed, leaving pits several kilometers wide and up to 100 m deep. These pits are reclaimed through a variety of treatments using subsoil or a mixed peat-mineral soil cap. Using nonmetric multidimensional scaling and cluster analysis of measurements of ecosystem function, reclamation treatments of several age classes were compared with a range of natural forest ecotypes to discover which treatments had created ecosystems similar to natural forest ecotypes and at what age this occurred. Ecosystem function was estimated from bioavailable nutrients, plant community composition, litter decomposition rate, and development of a surface organic layer. On the reclamation treatments, availability of nitrate, calcium, magnesium, and sulfur were generally higher than in the natural forest ecotypes, while ammonium, P, K, and Mn were generally lower. Reclamation treatments tended to have more bare ground, grasses, and forbs but less moss, lichen, shrubs, trees, or woody debris than natural forests. Rates of litter decomposition were lower on all reclamation treatments. Development of an organic layer appeared to be facilitated by the presence of shrubs. With repeated applications of fertilizers, measured variables for the peat-mineral amendments fell within the range of natural variability at about 20 yr. An intermediate subsoil layer reduced the need for fertilizer and conditions resembling natural forests were reached about 15 yr after a single fertilizer application. Treatments over tailings sand receiving only one application of fertilizer appeared to be on a different trajectory to a novel ecosystem.
在油砂开采过程中，所有植被、土壤、表土和油砂都被移除，留下宽达数公里、深达100米的矿坑。这些矿坑通过使用底土或泥炭 - 矿物混合土覆盖层的各种处理方法进行复垦。利用非度量多维标度法和生态系统功能测量的聚类分析，将几个年龄组的复垦处理与一系列天然森林生态型进行比较，以发现哪些处理创造了与天然森林生态型相似的生态系统以及这发生在什么年龄。生态系统功能通过生物可利用养分、植物群落组成、凋落物分解率和表层有机层的发育来估计。在复垦处理中，硝酸盐、钙、镁和硫的有效性通常高于天然森林生态型，而铵、磷、钾和锰的有效性通常较低。与天然森林相比，复垦处理往往有更多的裸地、草本植物和阔叶杂草，但苔藓、地衣、灌木、树木或木质残体较少。所有复垦处理的凋落物分解率都较低。灌木的存在似乎促进了有机层的发育。通过反复施肥，泥炭 - 矿物改良剂的测量变量在约20年后落入自然变异性范围内。中间的底土层减少了对肥料的需求，在单次施肥后约15年达到了类似天然森林的条件。仅接受一次肥料施用处理的尾矿砂处理似乎处于与新生态系统不同的发展轨迹。
