Fire in the Arctic Landscape: Impacts, interactions and links to global and regional environmental change

Between July 16 and October 1, 2007, the “Anaktuvuk River” (AR) fire burned over 1000 km2 (400 square miles) of tundra on the North Slope of Alaska (see Figure to the right). This was the largest fire in Alaska in 2007 (http://fire.ak.blm.gov/), and it would be considered a very large fire in any year, even in a more fire-prone landscape like boreal forest. What is particularly remarkable about the AR fire is that it burned on the treeless tundra where small fires occasionally burn but large ones are quite rare; the area burned in this one fire is equal to the total area burned by all recorded fires on the North Slope since 1950 (Jones et al., 2009, Racine and Jandt 2008; http://agdc.usgs.gov/data/blm/fire/index.html). The AR fire was large enough to include several complete 1st-3rd order watersheds, and most of the burned area was classified as “high” or “extremely high” severity by BLM fire severity standards (G. Shaver personal observation, R. Jandt BLM fire survey trip report July 2008). All of the land burned in the AR fire is in the foothills region of the North Slope, including diverse tundra, streams, lakes, and wetlands at elevations of 200-600 m. The dominant vegetation is moist acidic tundra, characterized by the tussock-forming sedge Eriophorum vaginatum (Walker et al. 1989, 2003). The 2007 Anaktuvuk River fire created a unique opportunity to observe the response of a pristine tundra landscape to a major disturbance. The area burned is large enough (>1000 km2) that its impacts can be measured directly at multiple scales, from small plots, to small (1st-order) catchments and hillslopes, to large (3rd-order) catchments, to the atmospheric boundary layer above the entire burn. As the burned area recovers over time, observations of changes in key ecosystem processes and in terrestrial and aquatic communities afford insights into controls and interactions among system components that would not be possible from long-term observation of an undisturbed or unmanipulated tundra landscape. This project establishes a long-term, multiscale, multidimensional program of observation, comparison, and analysis on the AR fire. The observations, comparisons, and analysis build upon work begun in 2008 (the first summer following the fire) with SGER funds from the NSF Arctic Systems Science and NEON programs. Key components of the research include measurement of (1) surface C, water, and energy exchanges, (2) terrestrial organic matter, C, and element stocks, (3) terrestrial vegetation composition and structure, (4) lake and stream chemistry and water flow, (5) lake and stream community composition, and (6) evaluation of spectral reflectance measures of production, biomass, community composition, and burn impacts for use in scaling up to larger areas and for comparison with satellite- and airplane based measures of reflectance.   References Jones, B.M., C.A. Kolden, R. Jandt, J.T. Abatzoglou, F. Urban, and C.D. Arp. 2009. Fire Behavior, Weather, and Burn Severity of the 2007 Anaktuvuk River Tundra Fire, North Slope, Alaska. Arctic, Antarctic, and Alpine Research 41(3): 309–316. Racine, C.H., and R. Jandt. 2008. The 2007 ‘Anaktuvuk River’ Tundra Fire On The Arctic Slope of Alaska: A New Phenomenon? Proceedings Ninth International Conference on Permafrost, in press Walker, M.D., D.W. Walker, and K.R. Everett. 1989. Wetland soils and vegetation, arctic foothills, Alaska. US Fish and Wildlife Service Biological Report 89(7). 89 pp. Walker, M.D., D.A. Walker, and N.A. Auerbach. 2003. Plant communities of a tussock tundra landscape in the Brooks Range foothills, Alaska. Journal of Vegetation Science 5: 843- 867.

Abstract: 

Increased temperatures in Northern Alaska over the past 50 years have been accompanied by an increase in the frequency of wildfires, with over half of the fire activity on the North Slope in the past 60 years occurring since 2000. The effects of fire on carbon and energy balances in this region are poorly understood, as the fires have occurred in remote regions, been small in size, and are relatively infrequent. Arctic ecosystems store twice the amount of carbon currently in the atmosphere and affect the local and regional climate by exchanging carbon with the atmosphere and through their impacts on the reflectivity of the tundra surface and heat penetration into permafrost soils. Fires have potential to alter the balances by releasing carbon into the atmosphere through combustion, reducing carbon sequestration through vegetation and soil changes, and influencing climate by darkening the surface and allowing more solar energy to be absorbed. The goal of this research is to develop a better understanding of the short-term (daily to annual) and long-term (decadal to centennial) effects of fire on Arctic tundra. The goal will be met by combining field measurements made at burned sites of different age on the North Slope and Seward Peninsula of Alaska, along with recent and historical satellite and aircraft remotely sensed imagery, into predictive models of how fires influence carbon and energy cycling over time across the Arctic. The models developed in this project can be used to inform future management decisions by predicting the impacts of future changes in the frequency of fires on ecosystem services in the Arctic. It will reveal processes and interactions that are relevant not only to the global human population as related to climate change, but also to the local Native American populations that depend on the North Slope landscape to sustain their subsistence lifestyles. Several postdoctoral and undergraduate researchers will be trained and contributions made to outreach programs currently run by the Arctic Long-Term Ecological Research project and the Marine Biological Laboratory. These contributions include internet-based distribution of data collected and models created, as well as public lectures and classroom exercises in local Native Alaskan communities.