Biological communities in reclaimed post-mining landscapes of British Columbia: From monitoring to management

This thesis explores the use of DNA-based tools to monitor ecological recovery in post-mining landscapes, with studies at two mines in British Columbia: Mount Milligan and Teck Highland Valley Copper. Biological monitoring in mine reclamation traditionally relies on vegetation and soil development, which occur slowly and may delay adaptive management. In contrast, microbial and invertebrate communities respond more rapidly to environmental change, offering potential as early indicators of reclamation success. This research uses DNA sequencing techniques to examine microbial and invertebrate communities across various reclamation strategies and reference conditions, with the aim of assessing biological community responses and informing future frameworks. Research at Teck Highland Valley Copper Mine focused on the long-term effects of biosolids amendments on microbial communities in reclaimed tailings storage facilities. Soil samples collected in 2015 from plots that received different one-time biosolids applications were analyzed for bacterial and fungal composition using DNA metabarcode sequencing. Diversity metrics and community composition were compared across treatment types, and results demonstrated that biosolids amendments had significant effects on microbial communities. Community composition analyses revealed distinct assemblages associated with biosolids treatments, suggesting that they strongly influence microbial abundance and community structure. Furthermore, the detection of increased abundances of antimicrobial resistance genes in biosolids-treated plots highlights important considerations for their use in mining reclamation. The second study, at Mount Milligan Mine, assessed microbial and invertebrate communities from 2022 to 2024 across reclaimed plots, bare ground, as well as naturally and anthropogenically disturbed reference ecosystems. Soil and invertebrate samples were collected and processed for DNA metabarcode sequencing to analyze bacterial, fungal, and invertebrate community diversity and composition. Results showed that communities differed significantly between reclamation and reference sites, revealing distinct microbial and invertebrate assemblages between site types. Certain bacterial, fungal, and invertebrate taxa were consistently associated with reclamation or reference site types, highlighting their value as potential bioindicators. Additionally, protocols for extracting and size-selecting high-molecular-weight DNA from soil were tested and refined to support future functional analyses using long-read sequencing. Together, this research demonstrates that DNA-based monitoring can detect meaningful differences in microbial and invertebrate communities across treatments and disturbance histories. These methods provide sensitive, high-resolution data that complement traditional monitoring approaches and could accelerate early detection of reclamation trajectories. By identifying specific indicator taxa linked to reclamation and evaluating the effects of varying treatments, this thesis contributes to the development of more adaptive and informative reclamation frameworks. The findings support the inclusion of microbial and invertebrate indicators in reclamation practices, and the thesis provides practical recommendations for future reclamation frameworks in British Columbia.