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 km2 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.

Highlights

  • Climate change is occurring rapidly at high latitudes, where surface air temperature has increased at twice the rate of the rest of the globe in the past decades [1,2]

  • To assess whether biomass allocation was altered following fire, we looked at the relationships between root biomass and Above-ground net primary production (ANPP) or leaf biomass

  • Despite the high severity of the Anaktuvuk River fire, ANPP of vascular plants in both moderately burned and severely burned tundra had recovered to the unburned level by 4 years following the fire

Read more

Summary

Introduction

Climate change is occurring rapidly at high latitudes, where surface air temperature has increased at twice the rate of the rest of the globe in the past decades [1,2]. Soils underlain by permafrost in Arctic and boreal regions are estimated to hold nearly twice the total amount of C as is in the atmosphere [8], so increased fire frequency in tundra may alter the magnitude of Arctic feedbacks to global climate that are already occurring in response to climate warming In addition to these direct effects, wildfire changes the composition and structure of vegetation in the short-term, and in the long-term if wildfire alters the successional trajectory. To measure recovery of vegetation and soils 4 years after the fire, in July 2011, we harvested biomass and soils along six 50m-long transects located either within or near the southeastern portion of the Anaktuvuk River fire scar (table 1), roughly 37 km NW of the Toolik Field Station (68.5838 N, 149.7178 W), which is the site of the Arctic Long-Term Ecological Research (LTER) programme. Differences that could not be detected with the sampling design would be small compared with those that were detected, and are unlikely to explain the patterns that we saw

Results
Eriophorum roots other rootsc
Eriophorum roots
Discussion
Findings
Plant species composition and productivity
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.