Effects of Wildfire Severity on Early Successional Dynamics in Boreal Peatland Complexes

• Main Author: Ernst, Elizabeth
• Format: Text
• Language: unknown
• Published: Digital Commons @ Michigan Tech 2017
• Subjects: Arctic; Great Slave Lake; Northwest Territories
• Online Access: https://digitalcommons.mtu.edu/etdr/330; https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1474&context=etdr

The Arctic-boreal region is experiencing changes in climate, trending toward warmer summers, resulting in a greater occurrence of wildfires with longer burning periods and higher intensities. Drought-like conditions dry surface fuels, leading to a higher probability of ignition, even in lowland peatlands. Previous work has been done to characterize post-fire succession rates in boreal upland sites, but much less is known of fire effects and early successional dynamics in lowland peatlands. Areas surrounding the Great Slave Lake in Canada’s Northwest Territories experienced exceptional wildfire activity in 2014 and 2015. These fires burned a variety of ecotypes, including bogs, fens, other lowlands, and uplands. To relate fire severity to early succession following wildfires, we collected seedling regeneration data in 2015 and 2016 and used mixed modeling and multivariate analyses to relate patterns in post-fire succession to burn severity metrics. Our study quantified burn severity at the surface, shrub, and canopy layers at several burned sites across ecotypes. We found that the most significant indicator of early regeneration of coniferous trees were severe ground fires, with canopy severity having little influence on successional patterns. Patterns of early succession of deciduous trees, however, related more to canopy severity. This work adds much needed context for post-fire succession in boreal peatland ecosystems, as the susceptibility of these systems to burning will continue to increase with a warming climate.