In northern Alberta, Canada, much of treed boreal peatlands are fragmented by seismic lines – linear disturbances where trees and shrubs are cleared for the exploration of fossil fuel reserves. Seismic lines have been shown to have slow tree regeneration, likely due to the loss of microtopography during the creation of seismic lines. Inverted soil mounding is one of the treatments commonly applied in Alberta to restore seismic lines and to mitigate the use of these corridors by wildlife and humans. In 2018, we assessed the effects of mounding on understory plants and arthropod assemblages, three years after treatment application. We sampled in five mounded and five untreated seismic lines, and in their adjacent treed fens (reference fens) within the Canadian Natural Resources Ltd (CNRL) Kirby South in-situ steam-assisted gravity drainage (SAGD) Plant, in the Athabasca oil sands (55°22'37.2" N, 111°10'3" W) of NW Alberta. Here we provide the species composition at these sites.

Ten sites that have been disturbed by a seismic line were selected, five of which were treated by applying inverted soil mounding. Two parallel 50-m-long transects were established at each site, one along the seismic line and the other 50 m into the adjacent fen. A sampling point (plot) was established every 10 m along each transect. In mounded areas, the mound closest to the sampling point was selected. At each sampling point, a 1x1 m quadrat and a pitfall trap (with propylene glycol as preservative) were installed to collect understory vegetation and ground-dwelling invertebrate data, respectively. Vegetation data were collected in a 10-day period in July 2018, and invertebrates were collected from May to September of the same year.