Canadian Forest Service Publications
Seismic line edge effects on plants, lichens and their environmental conditions in boreal peatlands of Northwest Alberta (Canada). 2021. Dabros, A.; Higgins, K.L.; Pinzon, J. Restoration Ecology 30(4):e13468.
Issued by: Northern Forestry Centre
Catalog ID: 40454
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Boreal peatlands of Alberta (Canada) are heavily dissected by a large network of linear disturbances, including seismic lines used for Oil and Gas exploration. Edge effects resulting from these linear disturbances can increase their footprint and affect wildlife habitat, including the quality and quantity of plant and lichen forage. In 2012, seismic line restoration became a priority in Alberta, under the realm of restoration of habitat of threatened boreal woodland caribou. More accurate understanding of biotic and abiotic interactions leading to edge effects can be important in choosing appropriate restoration practices and prompting natural regeneration. We assessed the extent of edge effects of seismic lines on the adjacent boreal peatland near Peace River, northwestern Alberta. We compared plant and lichen community composition and environmental conditions on seismic lines and along 22 transects, which extended perpendicularly 75 m into the peatland from both lines edges. Soil moisture and light were higher on the lines, but frozen ground was less frequent than in the adjacent peatland. Seismic lines were also subsided by approximately 1.2 cm. Lichens were less abundant in the 2–25 m zone from the edge—indicating edge effects. On the lines, Sphagnum constituted a nearly 100% cover while lichens, trees, herbs, and other bryophytes were less abundant than in the peatland. We demonstrate how knowledge of edge effects on plants and lichens could be applied in assessing caribou habitat quality based on forage availability and predation risk, and how such knowledge could inform restoration practices of seismic lines in peatlands.
Plain Language Summary
Boreal peatlands of Alberta (Canada) are disturbed by Oil and Gas industrial development, including seismic lines, which are used to determine the presence and depth of underground Oil and Gas. From the 1920s to the 1990s, 5–10 m wide corridors, currently termed as “conventional seismic lines” were constructed using heavy bulldozers, compacting the soil, and clearing trees and often ground layer vegetation in the process. Over many decades since their construction, seismic lines have frequently shown slow recovery to pre-disturbance conditions in boreal peatlands. In Alberta, peatlands account for slightly over 100,000 km2 of the land base. Within this area, seismic lines are estimated to extend at least 345,000 km in length. We assessed plant and lichen species composition on the lines and in the adjacent to the line peatland, near Peace River, NW Alberta. Our objective was to assess if the impact of the line extend beyond its edges (edge effects), and if yes, how far. We also compared soil moisture, soil temperature, light levels, elevation, and presence of soil ice on the lines and in the adjacent peatland. Soil moisture and light were higher on the lines, but frozen ground was less frequent than in the adjacent peatland. Seismic lines were also lower in elevation by ~1.2 cm. Lichens (which are important food source for threatened caribou) were less abundant in the 2-25 m zone from the edge – indicating edge effects. On the lines, peat moss constituted a nearly 100% cover while lichens, trees, herbaceous plants, and other mosses were less abundant than in the peatland. We demonstrate how knowledge of edge effects on plants, lichens and environmental factors can be used planning restoration measures in peatlands. We also discuss our results in the context of how edge effects can affect the quality of caribou habitat, based on the plant food source quality and availability, and risk of caribou predation by wolves and bears.