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| Titel |
Wetland succession in a permafrost collapse: interactions between fire and thermokarst |
| VerfasserIn |
I. H. Myers-Smith, J. W. Harden, M. Wilmking, C. C. Fuller, A. D. McGuire, F. S. Chapin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 5 ; Nr. 5, no. 5 (2008-09-05), S.1273-1286 |
| Datensatznummer |
250002825
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| Publikation (Nr.) |
 copernicus.org/bg-5-1273-2008.pdf |
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| Zusammenfassung |
| To determine the influence of fire and thermokarst in a boreal landscape,
we investigated peat cores within and adjacent to a permafrost collapse
feature on the Tanana River Floodplain of Interior Alaska. Radioisotope
dating, diatom assemblages, plant macrofossils, charcoal fragments, and
carbon and nitrogen content of the peat profile indicate ~600 years of
vegetation succession with a transition from a terrestrial forest to a
sedge-dominated wetland over 100 years ago, and to a
Sphagnum-dominated peatland in approximately 1970. The shift from
sedge to Sphagnum, and a decrease in the detrended tree-ring width
index of black spruce trees adjacent to the collapse coincided with an
increase in the growing season temperature record from Fairbanks. This
concurrent wetland succession and reduced growth of black spruce trees
indicates a step-wise ecosystem-level response to a change in regional
climate. In 2001, fire was observed coincident with permafrost collapse and
resulted in lateral expansion of the peatland. These observations and the
peat profile suggest that future warming and/or increased fire disturbance
could promote permafrost degradation, peatland expansion, and increase carbon
storage across this landscape; however, the development of drought conditions
could reduce the success of both black spruce and Sphagnum, and
potentially decrease the long-term ecosystem carbon storage. |
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