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| Titel |
Surtsey and Mount St. Helens: a comparison of early succession rates |
| VerfasserIn |
R. del Moral, B. Magnusson |
| 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 ; 11, no. 7 ; Nr. 11, no. 7 (2014-04-14), S.2099-2111 |
| Datensatznummer |
250117360
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| Publikation (Nr.) |
 copernicus.org/bg-11-2099-2014.pdf |
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| Zusammenfassung |
| Surtsey and Mount St. Helens are celebrated but very different volcanoes.
Permanent plots allow for comparisons that reveal mechanisms that control
succession and its rate and suggest general principles. We estimated rates
from structure development, species composition using detrended
correspondence analysis (DCA), changes in Euclidean distance (ED) of DCA
vectors, and by principal components analysis (PCA) of DCA. On Surtsey, rates
determined from DCA trajectory analyses decreased as follows: gull colony on
lava with sand > gull colony on lava, no sand ≫ lava with
sand > sand spit > block lava > tephra. On Mount St. Helens,
plots on lahar deposits near woodlands were best developed. The succession
rates of open meadows declined as follows: Lupinus-dominated
pumice > protected ridge with Lupinus > other pumice and
blasted sites > isolated lahar meadows > barren plain. Despite the
prominent contrasts between the volcanoes, we found several common themes.
Isolation restricted the number of colonists on Surtsey and to a lesser
degree on Mount St. Helens. Nutrient input from outside the system was
crucial. On Surtsey, seabirds fashioned very fertile substrates, while on
Mount St. Helens wind brought a sparse nutrient rain, then Lupinus
enhanced fertility to promote succession. Environmental stress limits
succession in both cases. On Surtsey, bare lava, compacted tephra and
infertile sands restrict development. On Mount St. Helens, exposure to wind
and infertility slow succession. |
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