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| Titel |
Spatiotemporal patterns of tundra fires: late-Quaternary charcoal records from Alaska |
| VerfasserIn |
M. L. Chipman, V. Hudspith, P. E. Higuera, P. A. Duffy, R. Kelly, W. W. Oswald, F. S. Hu |
| 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 ; 12, no. 13 ; Nr. 12, no. 13 (2015-07-03), S.4017-4027 |
| Datensatznummer |
250118010
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| Publikation (Nr.) |
 copernicus.org/bg-12-4017-2015.pdf |
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| Zusammenfassung |
| Anthropogenic climate change has altered many ecosystem processes in the
Arctic tundra and may have resulted in unprecedented fire activity.
Evaluating the significance of recent fires requires knowledge from the
paleofire record because observational data in the Arctic span only several
decades, much shorter than the natural fire rotation in Arctic tundra
regions. Here we report results of charcoal analysis on lake sediments from
four Alaskan lakes to infer the broad spatial and temporal patterns of
tundra-fire occurrence over the past 35 000 years. Background charcoal
accumulation rates are low in all records (range is 0–0.05 pieces cm−2 yr−1),
suggesting minimal biomass burning across our study areas.
Charcoal peak analysis reveals that the mean fire-return interval (FRI;
years between consecutive fire events) ranged from ca. 1650 to 6050 years at
our sites, and that the most recent fire events occurred from ca. 880 to 7030
years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI
estimates are longer than the fire rotation periods estimated for the past
63 years in the areas surrounding three of the four study lakes. This result
suggests that the frequency of tundra burning was higher over the recent
past compared to the late Quaternary in some tundra regions. However, the
ranges of FRI estimates from our paleofire records overlap with the
expected values based on fire-rotation-period estimates from the
observational fire data, and the differences are statistically
insignificant. Together with previous tundra-fire reconstructions, these
data suggest that the rate of tundra burning was spatially variable and that
fires were extremely rare in our study areas throughout the late Quaternary.
Given the rarity of tundra burning over multiple millennia in our study
areas and the pronounced effects of fire on tundra ecosystem processes such
as carbon cycling, dramatic tundra ecosystem changes are expected if
anthropogenic climate change leads to more frequent tundra fires. |
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