Abstract: The revegetation of northern tailings sites presents many challenges. By using plants, which are naturally adapted to both the tailings environment and northern climatic conditions, fewer amendments and intervention will be required. In 2003, vegetation growing on and off the tailings and soil at three Yukon Territory, Canada, mine sites (United Keno Hill, Mount Skukum, and Wellgreen) was assessed and soil samples were collected. Through Canonical Correspondence Analysis (CCA), a statistical program that assesses relationships between plant species and environmental variables, I found that these plant communities are largely governed by a chemical-nutrient gradient (heavy metals and nutrients) and a ground cover gradient (bare and exposed conditions compared with full ground cover). The native grass Deschampsia caespitosa L. Beauv. was found colonizing all three tailings sites and its presence was associated with low nutrients, high heavy metal levels, and exposed ground, but it was also a habitat generalist. Five Yukon populations of D. caespitosa, originating from mine and uncontaminated sites were tested hydroponically for their tolerance to elevated Ni, Zn, and Cd concentrations. Intrinsic multiple metal tolerance occurred in all populations. In revegetation field trials in the Yukon, I planted seeds and transplants of 7 populations of D. caespitosa under different treatments: i) untreated, ii) compost, iii) fertilizer, and iv) combined (compost and fertilizer). At all sites, during the two years of data collection, local and non-local populations, including those from non-contaminated sites were able to establish, grow, and reproduce, even in unamended tailings and despite successive hot and dry summers. D. caespitosa also acted as a nurse crop, facilitating invasion of plants from adjacent habitats. The short term results suggest that the inclusion of Deschampsia caespitosa as a nurse crop for the revegetation of these northern mine tailings sites will be beneficial.

Authors: Clark, A. and Hutchinson, T.

Map Scale: 1 : 0

NTS Mapsheet(s): 105M14

Citation: Clark, A. and Hutchinson, T., 2005. Enhancing Natural Succession on Yukon Mine Tailings Sites: A low-input Management Approach. Mining & Petroleum Environment Research Group, 2005-3.

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