Canadian Forest Service Publications

Plant community development following reclamation of oil sands mine sites in the boreal forest: a review. 2018. Dhar, A.; Comeau, P.G.; Karst, J.; Pinno, B.D.; Chang, S.X.; Naeth, A.M.; Vassov, R.; Bampfylde, C. Environmental Reviews 26(3):286-298.

Year: 2018

Issued by: Northern Forestry Centre

Catalog ID: 39552

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1139/er-2017-0091

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Understanding how reclamation practices influence plant community assembly and succession is an important step in developing realistic indicators and targets for reclamation of oil sands mine sites to upland forest ecosystems. We currently have a poor understanding of factors affecting plant community assembly and succession in reclaimed oil sands sites. Through synthesis of research completed over the last 24 years, we identify four key findings: (i) use of surface soil and forest floor material salvaged from mined areas increases plant species cover, richness, and diversity relative to the use of various other cover soil materials (such as clay subsoil); (ii) stockpiling of salvaged surface soils decreases the abundance of native plant propagules and delays early vegetation community development; (iii) differences in plant community composition between reclaimed and adjacent mature forests remain two decades after placing cover soils; however, differences are smaller with use of forest floor–mineral mix than peat–mineral mix; and (iv) plant community assembly is in progress but communities remain different to those found in natural undisturbed conditions. Our review identified critical knowledge gaps for further research to improve understanding of: (i) long-term (60 to 100 years) plant community composition in reclaimed oil sands sites; (ii) how residual forest patches near disturbed oil sands sites act as seed and propagule sources in newly reclaimed sites; (iii) plant community assembly processes in reclamation sites; (iv) the effect of micro-topographic heterogeneity on plant community development; and (v) how soil nutrient availability in different substrates influences plant community development over the long term. Ongoing support for selected existing studies and establishment of new studies focusing on plant community development through long-term monitoring are highly recommended

Plain Language Summary

Mining affects more than two billion hectares worldwide. After a forested site has been mined, a key goal of restoration is to redevelop the forest ecosystem, including the variety of species present, their relative numbers, and their distribution on the site. We currently have a poor understanding of the factors that affect how communities of plants form on reclaimed oil sands sites and how they change over time. In this study, we synthesized information compiled over the last 24 years on oil sands reclamation in Alberta. We found that surface soil and forest floor material salvaged from the area is an excellent source of seeds and plant material that can be propagated, leading to more rapid development of vegetation cover and a higher diversity of native plant species than if other materials (such as clay subsoil) are spread over the site. If the salvaged material is stockpiled, the viability of seeds and organisms that live in the soil is reduced, delaying the establishment of vegetation on the site. Even if a forest floor–mineral mix is used, differences remain between the plant communities on reclaimed sites and those of adjusted mature forests two decades after reclamation. Our review also identified several critical knowledge gaps for further research.