NWT RESEARCH DATABASE

Tags: physical sciences, permafrost, vegetation, climate change, carbon fluxes, fire ecology

Objective(s): To look at how permafrost is changing following forest fire over a range of environmental conditions.

Project Description: The research goal is to look at how permafrost is changing following forest fire over a range of environmental conditions, with the purpose of improving how change is modelled in the future. The fires of 2014 in the southwestern NWT provide an opportunity to examine how discontinuous permafrost responds to disturbances. This work is being carried out in collaboration with an inter-university team of ecologists studying how vegetation responds to fire and the carbon cycle in the region. Burnt and unburnt sites covering the regional range of climatic, ecological, and permafrost conditions were established in 2015 along a transect from Yellowknife to Kakisa. A total of 17 sites were set up in 2015, and a further three in 2016. Unburnt control sites were chosen to determine the baseline impacts of climate change in the area. Air and ground temperature sensors were installed at each site, and left in place to monitor temperatures year-round. A geophysical technique called direct current electrical resistivity tomography (ERT) was undertaken at each site in the spring and the fall and this will continue in future years. For this technique the research team pass a small amount of electrical energy into the ground (this has no negative impacts on the environment), and it provides us with an image of where the ground is frozen and where it is unfrozen to a depth of at least 12 m. Small stainless steel rods called electrodes have been inserted into the ground and will stay there for the duration of the study so that measurements can be taken at the same places each year to monitor changes. The research team probe the depth of thaw at each of these electrodes at the end of summer. In 2016, permafrost cores were taken at each site using a two-person gasoline powered auger to understand the soil and ice conditions and for carbon stock assessments. In 2017, ERT resurveys will be completed at each site, and in historical burns of different ages to establish long term impacts on permafrost. In the long run, the team expect that the ERT measurements will show permafrost disappearing entirely at some sites due to the effect of the 2014 forest fires whereas at others the team may simply observe deeper thaw at the surface. A presentation is being organized to share research in Fort Providence in 2018. Research will be shared with other communities (Behchoko, Kakisa, Yellowknife) by presenting a poster at a community event or in a school where possible. A research presentation was arranged in Hay River to the Forest Management Group of Environment and Natural Resources, and an informal outreach activity was done around a camp-fire for kids and family showing some permafrost monitoring techniques. A presentation was made in Yellowknife in cooperation with Ecology North for interested public, and an interview was done on CBC radio discussing the research. Connection via email and phone was made with Chief Bonnetrouge of Fort Providence, and a booklet of research materials was dropped off for the community to view. A presentation will be given to the community in 2018. Similar undertakings will be done in future years. Presentations will also be made to interested communities (Kakisa, Behchoko, Fort Providence, Yellowknife). Since part of the project will be undertaken during the school year, contact will be made in the field with local school teachers to give class presentations if desired in the schools. Information about ground temperature will be made available within the proposed NWT Permafrost Database Project. The fieldwork for this study will be conducted from August 1, 2018 to September 30, 2018.