title: The response of Arctic vegetation and soils following an unusually severe tundra fire.
abstract: Fire causes dramatic short-term changes in vegetation and ecosystem function, and may promote rapid vegetation change by creating recruitment opportunities. Climate warming likely will increase the frequency of wildfire in the Arctic, where it is not common now. In 2007, the unusually severe Anaktuvuk River fire burned 1039 km(2) of tundra on Alaska's North Slope. Four years later, we harvested plant biomass and soils across a gradient of burn severity, to assess recovery. In burned areas, above-ground net primary productivity of vascular plants equalled that in unburned areas, though total live biomass was less. Graminoid biomass had recovered to unburned levels, but shrubs had not. Virtually all vascular plant biomass had resprouted from surviving underground parts; no non-native species were seen. However, bryophytes were mostly disturbance-adapted species, and non-vascular biomass had recovered less than vascular plant biomass. Soil nitrogen availability did not differ between burned and unburned sites. Graminoids showed allocation changes consistent with nitrogen stress. These patterns are similar to those seen following other, smaller tundra fires. Soil nitrogen limitation and the persistence of resprouters will likely lead to recovery of mixed shrub-sedge tussock tundra, unless permafrost thaws, as climate warms, more extensively than has yet occurred.
authors.affiliation: Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA. msbretharte@alaska.edu
authors.forename: M Syndonia
authors.initials: MS
authors.lastname: Bret-Harte
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Mack
authors.forename: Gaius R
authors.initials: GR
authors.lastname: Shaver
authors.forename: Diane C
authors.initials: DC
authors.lastname: Huebner
authors.forename: Miriam
authors.initials: M
authors.lastname: Johnston
authors.forename: Camilo A
authors.initials: CA
authors.lastname: Mojica
authors.forename: Camila
authors.initials: C
authors.lastname: Pizano
authors.forename: Julia A
authors.initials: JA
authors.lastname: Reiskind
mesh_terms: D001110:Arctic Regions; D018533:Biomass; D002244:Carbon; D057231:Climate Change; D017753:Ecosystem; D005390:Fires; D009584:Nitrogen; D010944:Plants; D012987:Soil
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen
keywords: Alaskan tussock tundra; climate change; fire; permafrost; soil N availability; vegetation recovery