Mapping the impacts of legacy oil wells and permafrost thaw on vegetation in the Northwest Territories, Canada

Thawing permafrost increasingly threatens the integrity of legacy sites from resource exploration and extractive industries. In the Northwest Territories, Canada, over 200 sumps containing drilling wastes within permafrost pose considerable environmental and health risks to local ecosystems and populations relying on the land for subsistence. Exploratory drilling activities have caused long-term disturbances to permafrost terrains and tundra vegetation, necessitating continued monitoring and research. This study investigates the complex interactions between legacy oil well disturbances, permafrost thaw, and vegetation changes. Using a combination of field-based and remote sensing techniques, we mapped and assessed the impacts of four drilling mud sumps located along the Inuvik-Tuktoyaktuk Highway (Northwest Territories, Canada). Multispectral drone surveys were conducted at the sites to produce high-resolution orthophotos, digital elevation models, landcover and vegetation index maps. Additionally, we measured the active layer thickness, percent cover of plant functional types, and canopy height within vegetation plots distributed along transects that covered both undisturbed and disturbed terrains. Here, we present preliminary findings from these investigations, including statistical and spatial analyses of the gathered data. Decades after decommissioning, the disturbances caused by the drilling mud sumps, coupled with permafrost degradation processes, continue to affect plant communities, shrub growth and vegetation productivity.