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| Titel |
River flooding as a driver of polygon dynamics: modern vegetation data and a millennial peat record from the Anabar River lowlands (Arctic Siberia) |
| VerfasserIn |
R. Zibulski, U. Herzschuh, L. A. Pestryakova, J. Wolter, S. Müller, N. Schilling, S. Wetterich, L. Schirrmeister, F. Tian |
| 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 ; 10, no. 8 ; Nr. 10, no. 8 (2013-08-28), S.5703-5728 |
| Datensatznummer |
250085314
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| Publikation (Nr.) |
 copernicus.org/bg-10-5703-2013.pdf |
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| Zusammenfassung |
| The spatial and temporal variability of a low-centred polygon on the eastern
floodplain area of the lower Anabar River (72.070° N,
113.921° E; northern Yakutia, Siberia) has been investigated using a
multi-method approach. The present-day vegetation in each square metre was
analysed, revealing a community of Larix, shrubby Betula,
and Salix on the polygon rim, a dominance of Carex and
Andromeda polifolia in the rim-to-pond transition zone, and a
predominantly monospecific Scorpidium scorpioides coverage within
the pond. The total organic carbon (TOC) content, TOC / TN (total nitrogen) ratio, grain size, vascular plant
macrofossils, moss remains, diatoms, and pollen were analysed for two
vertical sections and a sediment core from a transect across the polygon.
Radiocarbon dating indicates that the formation of the polygon started at
least 1500 yr ago; the general positions of the pond and rim have not
changed since that time. Two types of pond vegetation were identified,
indicating two contrasting development stages of the polygon. The first was a
well-established moss association, dominated by submerged or floating
Scorpidium scorpioides and/or Drepanocladus spp. and
overgrown by epiphytic diatoms such as Tabellaria flocculosa
and Eunotia taxa. This stage coincides temporally with a period in
which the polygon was only drained by lateral subsurface water flow, as
indicated by mixed grain sizes. A different moss association occurred during
times of repeated river flooding (indicated by homogeneous medium-grained
sand that probably accumulated during the annual spring snowmelt),
characterized by an abundance of Meesia triquetra and a dominance of
benthic diatoms (e.g. Navicula vulpina), indicative of a relatively
high pH and a high tolerance of disturbance. A comparison of the local
polygon vegetation (inferred from moss and macrofossil spectra) with the
regional vegetation (inferred from pollen spectra) indicated that the moss
association with Scorpidium scorpioides became established during
relatively favourable climatic conditions, while the association dominated by
Meesia triquetra occurred during periods of harsh climatic
conditions. Our study revealed a strong riverine influence (in addition to
climatic influences) on polygon development and the type of peat accumulated. |
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