Early boreal forest understory plant community development in reclaimed oil sands.
The understory is an important reservoir of plant biodiversity and a driver of ecological processes in Canada's boreal forest, making its re-establishment following reclamation of oil sands mines crucial. This study examined understory plant community development with time using two cover soil types (forest floor mineral mix (FMM) and peat mineral mix (PMM)) in Alberta oil sands reclamation sites. Cover soil type played a significant role in plant community development with FMM soil having greater species richness, diversity and total vegetation cover than PMM four years after reclamation. Nonmetric multi dimensional scaling and multi response permutation procedure revealed no compositional differences between the cover soil types. Indicator species analysis showed FMM cover soil was dominated by perennial species while PMM was dominated by annual forb species. This implies that FMM cover soil leads to faster vegetation recovery (from ruderal and annual communities to perennial communities) than PMM cover soil. Non-native species declined with time in FMM (7.5-4%) and increased in PMM (8.9-12.5%). We therefore recommend utilizing FMM as cover soil to promote productive and diverse understory plant communities on the reclaimed landscape.