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Title: On the use of mulching to mitigate permafrost thaw due to linear disturbances in sub-arctic peatlands

item MOHAMMED, AARON - University Of Western Ontario
item SCHINCARIOL, ROBERT - University Of Western Ontario
item QUINTON, WILLIAM - Wilfrid Laurier University
item NAGARE, RANJEET - Wilfrid Laurier University
item Flerchinger, Gerald

Submitted to: Ecological Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2017
Publication Date: 2/24/2017
Citation: Mohammed, A., Schincariol, R., Quinton, W., Nagare, R., Flerchinger, G.N. 2017. On the use of mulching to mitigate permafrost thaw due to linear disturbances in sub-arctic peatlands. Ecological Engineering. 102:207-223. doi: 10.1016/j.ecoleng.2017.02.020.

Interpretive Summary: Disturbance caused by resource exploration in the sub-arctic peatlands can cause degradation of the permafrost resulting in significant changes in the ecology and hydrology of these sensitive ecosystems. Laboratory and numerical modeling studies were conducted to test the efficacy of mulching disturbed areas with trees removed during exploration. Results indicate that mulching is effective and guidance was provided to ensure that northern exploration is performed in an environmentally sustainable manner.

Technical Abstract: The presence or absence of permafrost significantly influences the hydrology and ecology of northern watersheds. Resource exploration activities are currently having noticeable effects on hydrological and ecological processes in sub-arctic peatlands. Disturbances such as seismic cutlines can result in increased soil moisture, land subsidence, and deforestation, which cause permafrost degradation. This contributes to land-cover transformation, habitat and vegetation loss, and changes to basin hydrologic cycles. The resultant permafrost-degraded corridors comprise large portions of the drainage density of sub-arctic basins, and alter the region’s water and energy balances. Mulching over cutlines, with the removed tree canopy, has been proposed as a best management practice to help reduce this environmental impact. Here we present climate chamber and numerical modeling results which quantify the effects of mulching and its ability to limit permafrost thaw and alterations to the ground thermal regime. Overall, the thermal buffering ability of the mulch had beneficial effects on slowing thaw, due to its low thermal conductivity, which decouples the subsurface from meteorological forcing and impedes heat conduction. Results indicate that mulching is an effective technique to reduce permafrost thaw and provides a scientific basis to assess the mitigation measure on its ability to slow permafrost degradation. This study will provide guidance to ensure that northern exploration is performed in a more environmentally sustainable manner.