Biodiversity and Forest structure one year following the 2016 Fort McMurray (Alberta) fire event

Exploration practices for oil sands developments in the boreal forest of
western Canada create a network of thousands of kilometers of linear
features, particularly seismic lines that dissect these forests posing
significant environmental challenges. As wildfire is one of the prevalent
stand-replacing natural disturbances in the Canadian boreal forest, it is
an important driver of environmental change and stand development that may
contribute to the mitigation of such linear industrial footprint. Here, we
evaluate the short-term cumulative (also known as combined) effects of
seismic lines and wildfire on biodiversity and site conditions. One year
after the Horse River (Fort McMurray, Alberta) fire event in the spring of
2016, we compared dissected and undisturbed forests in burned and unburned
boreal peatlands, assessing changes in overall stand structure and the
responses of a variety of organisms. Soil moisture was significantly
higher on seismic lines than in the adjacent forest, suggesting why most
of the study sites within the fire perimeter showed little evidence of
burning at the line in relation to the adjacent forest. Low fire severity
on seismic lines seemed an important driver of local species diversity for
ants, beetles, spiders, and plants in disturbed peatlands, resulting in
similar species composition on seismic lines both within and outside the
burned area, but different assemblages in burned and unburned adjacent
forests. Our results suggest that fire did not erase seismic lines;
rather, wildfire might increase the influence of this footprint on the
recovering adjacent forest. Longer term monitoring will be necessary to
understand how boreal treed peatlands respond to the cumulative effect of
wildfire and linear disturbances.