Changing disturbance regimes and carbon cycle feedbacks to climate in a warming arctic

Michelle Cailin Mack, University of Florida, mcmack@ufl.edu (Presenter)
Heather Dawn Alexander, University of Florida, hdalexander@ufl.edu
Jill Francis Johnstone, University of Saskatchewan, jill.johnstone@usask.ca
Marion Syndonia Bret-Harte, University of Alaska Fairbanks, msbretharte@alaska.edu

A predicted consequence of climate warming in the arctic is an increase in the frequency, intensity and size of wildfires. Because arctic tundra and boreal forests store globally important stocks of carbon (C) in plants and soil, there has been considerable interest in understanding the effects of changing fire regimes on the C balance of these ecosystems. Fire rapidly releases C stored in plants and soil to the atmosphere, particularly if it burns deeply into organic soils characteristic of northern ecosystems. Over longer timescales, changes in organic soils can alter controls over ecosystem C dynamics by influencing plant species composition, nutrient availability, and the integrity of permafrost—permanently frozen soil. We addressed changing fire regimes in two arctic biomes: increasing fire severity in the boreal forests of Interior Alaska, where fire has been part of the historic disturbance regime, and unprecedented fire in the arctic tundra of Alaska’s North Slope, where fire has been largely absent since the early Holocene. For these two biomes, we compared C release during fire, patterns of burning, post-fire vegetation recovery, and integrity of permafrost to better understand the consequences of intensifying fire regimes for C cycling feedbacks to climate. We compare results from the 2007 Anaktuvuk River Fire, which burned over 1,000 square kilometers of arctic tundra, to results from recent and historic fires in the boreal forests of Interior Alaska.

Presentation Type:  Poster

Session:  Global Change Impact & Vulnerability   (Tue 11:30 AM)

Associated Project(s): 

• Goetz, Scott: Quantifying Changes in Northern High Latitude Ecosystems and Associated Feedbacks to the Climate System ...details
• Kasischke, Eric: Vulnerability and Resiliency of Arctic and Sub-Arctic Landscapes (VuRSAL) - the Role of Interactions between Climate, Permafrost, Hydrology, and Disturbance in Driving Ecosystem Processes ...details

Poster Location ID: 227