| Mining activity in Canada's subarctic Hudson Bay Lowland is increasing. It is now producing processed kimberlite waste and other mine wastes that must be reclaimed to novel upland ecosystems dominated by native plant species. Reclaiming these waste piles to regionally compatible, productive and self-sustaining ecosystems first requires an understanding of existing soils, plant communities and succession, and soil-plant relationships on analogous natural environments. Currently, little is known about these factors and relationships on existing uplands in this region.;The broad objective of this study was to determine regionally-relevant reference conditions of upland ecosystems to guide mine restoration. Specifically, objectives were to (i) describe existing upland plant communities and soil profiles in this region; (ii) describe the mean condition and the range of conditions for measured parameters; (iii) group similar plant communities and soils together; and (iv) characterize the variation of soils, vegetation and soil-plant relationships in these groups.;Key vegetation and soil characteristics were sampled in natural ecosystems near the De Beers Victor Mine, Ontario, Canada. A first series of sites were sampled along a natural successional gradient of well-drained riverbank sites (n=37). Interior natural uplands were also examined along a 150km east-west geological chronosequence beginning at James Bay ( n=34). Each site was sampled using existing protocols developed for forest ecosystem classification in northern Ontario, in which (i) vegetation in a 100 m2 plot was described, and (ii) soils were described a central soil pit in each plot. Vegetation parameters measured included vegetation structure and cover, species richness and species composition, tree height, DBH and age, and coarse woody debris. Soil parameters measured included depth and type of soil horizons, bulk density, soil moisture regime, rooting depth, and chemical characteristics of the horizon with the maximum rooting density, specifically, pH, cation exchange capacity, CNS content and bioavailable elements. Descriptive statistics were calculated for all quantitative variables. Plant species assemblages were identified using nonmetric multi-dimensional scaling and cluster analysis. Soil types were further elucidated using principal component analyses and cluster analyses on the chemistry of the principal rooting horizon.;Soils in the interior uplands were dominated by sandy textured Podzols and the uplands along the river were dominated by silty loam, slightly alkaline Regosols. Soils at interior and river upland sites differed from mine wastes in most chemical parameters and were separated in a PCA. However, on an individual soil parameter basis, mine wastes and reclamation materials from the Victor mine mostly fell within or close to ranges of soil parameters found at inland and river reference sites.;Vegetation across the two natural analogues could be separated into seven upland plant community groups. These plant community groups followed the classification of site types based on soils; two interior upland plant communities and four riverbank upland plant communities were identified, with another plant community from an abandoned gravel pit. Both along the river and in the interior, plant community groups differed in successional age. They ranged from early successional to mature and old growth ecosystems.;Plants from mid-successional stages of either reference condition can be used as reference targets on a reclaimed soil that incorporates qualities of substrates from both, but research trials will be required to determine which species will be most successful. As vegetation is established, the reference conditions can be used to as a benchmark to examine the relative success of the reclamation effort in achieving a community target.;The variability described in the natural ecosystems will provide bounds for creating regionally compatible upland ecosystems on mine waste rock. These reference conditions offer a template of possible successional trajectories and community targets in similar environments, and a repeatable method for doing so in alternate environments. |
