Please use this identifier to cite or link to this item:
http://hdl.handle.net/11375/25114
Title: | Ecohydrological Thresholds to High Peat Burn Severity: Implications for Peatland Wildfire Management |
Other Titles: | Ecohydrological Thresholds to High Peat Burn Severity |
Authors: | Wilkinson, Sophie |
Advisor: | Waddington, James Michael |
Department: | Earth and Environmental Sciences |
Keywords: | Wildfire;Peat;Carbon;Hydrology;Peatland;Climate Change |
Publication Date: | 2019 |
Abstract: | Northern peatlands represent a globally significant carbon stock, equating to almost one-third of the world’s organic soil carbon. The largest areal disturbance to northern peatlands is wildfire where carbon loss, through peat smouldering combustion, is highly variable. The tightly-coupled ecohydrological nature of peatlands results in autogenic feedbacks and the occurrence of threshold behaviour. High depth of burn has been evidenced in black spruce dominated peatlands in the sub-humid Boreal Plains ecozone of Alberta, Canada so this was chosen as the area of study. A landscape-scale assessment of peat hydrophysical properties found that peat smouldering combustion vulnerability was greatest at stand-age > 80 years, in coarse/heterogeneous hydrogeological settings, and in peatland margins compared to peatland middles. In combination, and when exposed to a climatic water deficit, we found that these drivers of cross-scale variability could lead to high peat burn severity. Assessment of a partially-drained and burned peatland enabled the identification of a black spruce basal diameter threshold that corresponded to the occurrence of high peat burn severity. We suggest that the above-ground fuel load threshold could occur due to the initiation of a self-reinforcing feedback by anthropogenic disturbance or climate change. Moreover, surpassing a peat burn severity threshold can cause the breakdown of an important feedback that limits evaporation losses post-fire, likely leading to further carbon losses through increased decomposition rates and/or ecosystem regime shift. We found that although peat moisture content was increased by fuel modification treatment, combustion carbon losses were greater in fuel-treated areas compared to the control because of the addition of mulch (wood) to the surface. Hence, peatland wildfire management that integrates the modification of above- and below-ground fuels, considers ecohydrological thresholds, and drivers of cross scale variability, is required to effectively reduce the risk of high peat burn severity in black spruce dominated peatlands. |
URI: | http://hdl.handle.net/11375/25114 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Wilkinson_Sophie_L_finalsubmission201912_PhD.pdf | 2.89 MB | Adobe PDF | View/Open |
Items in MacSphere are protected by copyright, with all rights reserved, unless otherwise indicated.