Northern Peatland Vulnerability to Wildfires

In a drying global climate, northern peatlands (particularly those that have been mined or drained) are at risk for experiencing high-frequency fires and degrading carbon stocks. Mitigating the risk of deep burning through restoration efforts such as rewetting are critical for the protection and preservation of these peatlands.

McMaster Researcher

Citation

Kettridge N., Turetsky M.R., Sherwood J.H., Thompson D.K., Miller C.A., Benscoter B.W., Flannigan M.D., Wotton B.M., & Waddington J.M., "Moderate drop in water table increases peatland vulnerability to post-fire regime shift," Nature Scientific Reports, 5, 8063, (2015). 

Granath G., Moore P.A., Lukenback M.C., & Waddington J.M., " Mitigating wild fire carbon loss in managed northern peatlands through restoration,"  Nature Scientific Reports, (2016).

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What is this research about?

A significant stock of Earth's carbon reserve is in the northern peatlands. The waterlogged and ecological properties of these peatlands make them resilient to large wildfires. However, the warming global climate suggests that northern peatlands will experience drying in the future. Drying of the northern peatlands will lead to drops in water table levels, making them more susceptible to high-frequency fire cycles and degrading their carbon stock. Over the course of two separate studies, this research examines the post-fire recovery of a northern peatland that had experienced a moderate drop in its water table level due to draining, and analyzes the risk of deep burning and management strategies to mitigate deep burning in natural, drained, mined, and restored peatlands. 

What did the researchers do?

In the first study, the researchers examined the post-fire recovery of the Saulteaux River poor fen in Alberta, Canada, which had been partially drained in 1983 and burned during a wildfire in 2001. In 2010, the researchers took measurements of water table levels and soil-water pressure, sampled understory and surface plant species, and calculated specific yield, species similarity, and light transmissivity from both the drained and undrained portions of the fen.  In the second study, the researchers used the Canadian Regional Climate Model to compare past and predicted future climate data for North America and northern Europe in order to understand the maximum potential water deficit that the peatlands may experience. Then, using newly collected data and literature data on bulk density and mean seasonal water table position from natural, drained, mined, and restored peatlands in northern European and North American, the researchers predicted water table positions for the various peatlands. They used these predictions to create a model that can compare the risk of deep burning in natural, drained, mined, and restored northern peatlands. 

What did the researchers find?

In the first study, the researchers concluded that northern peatlands exposed to drainage and burning have the potential to transform into shrublands that are susceptible to high-frequency wildfires and degrading carbon stocks. The researchers came to this conclusion through a few findings. First, the researchers found that the loss of water required to lower water table position was significantly smaller in portions of the Saulteaux peatland that were drained or burned, or that had been drained and burned. Secondly, the researchers found that the undrained portions of the peatland followed a resilient post-fire recovery pattern typical of northern peatlands. That is, after the wildfire, the undrained portions of the peatland had a high specific yield and maintained high water table levels, which promoted the reestablishment of a Sphagnum moss-dominant ecosystem that helped recover carbon levels lost in the fire. In contrast, the drained portions of the peatland did not follow a post-fire recovery pattern typical of northern peatlands. After the wildfire, the drained portions of the peatland had a low specific yield and Sphagnum moss cover was significantly reduced. These areas were colonized by willow and birch, which limited light transmissivity and prevented moss from re-establishing.  

In the second study, the researchers found that drained and mined peatlands are at a greater risk for deep burning compared to natural and restored peatlands, particularly in anticipation of a drying global climate. The researchers came to this conclusion after finding that there will be less water available in the future across northern Europe and North America (particularly in the temperate and tundra zones) and that, given the same water deficit and initial conditions, drained and mined peatlands experience significantly greater reductions in water table position compared to natural and restored peatlands. The researchers suggest that strategies such as rewetting of drained peatlands are important restoration techniques, especially if Sphagnum moss coverage can be re-established. 

How can you use this research?

Given the knowledge we have about the negative financial, environmental, and health effects resulting from burning tropical peatlands, this research is useful to academics, environmentalists, and policymakers in their efforts to protect northern peatlands from deep burning. This research is also important in emphasizing that, ultimately, efforts to curb climate change are the key to protecting northern peatlands from catastrophic wildfires.  

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