A data compilation and synthesis of the impacts of seismic surveys on surface soil properties in boreal Alberta, Canada

Abstract

Linear clearings of vegetation to perform geophysical surveys, called seismic lines, are created for oil and gas exploration in boreal Canada and often persist on the landscape for decades after disturbance. Therefore, an assessment of environmental conditions on seismic lines is needed to inform restoration efforts. This study aimed to compile surface soil properties (upper 5–15 cm; dry bulk density, organic matter content, organic matter bulk density, volumetric water content, and water content by mass) on and off seismic lines across upland, transitional, and peatland ecosystems in northern Alberta, Canada (N=1,638). Soil properties differ between seismic line and reference samples, especially on older ‘conventional’ lines. Changes included higher dry bulk density, lower organic matter content, and elimination of microtopographic variability. Changes in dry bulk density can, in part, be explained by a reduction in organic matter content, but altered carbon cycling and/or compaction are also important. Restoration techniques such as inverted mounding create an entirely distinct soil condition, with higher mean bulk densities and lower organic matter contents than both on and off seismic lines. Therefore, an assessment of microtopographic recovery should be conducted before prescribing restoration treatments to limit further degradation of soil structure.