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| Titel |
Pollen, vegetation change and climate at Lake Barombi Mbo (Cameroon) during the last ca. 33 000 cal yr BP: a numerical approach |
| VerfasserIn |
J. Lebamba, A. Vincens, J. Maley |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 1 ; Nr. 8, no. 1 (2012-01-05), S.59-78 |
| Datensatznummer |
250005361
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| Publikation (Nr.) |
 copernicus.org/cp-8-59-2012.pdf |
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| Zusammenfassung |
| This paper presents quantitative reconstructions of
vegetation and climate along the pollen sequence of Lake Barombi Mbo,
southwestern Cameroon (4°39'45.75" N, 9°23'51.63" E, 303 m a.s.l.) during the last 33 000 cal yr BP, improving previous empirical
interpretations. The biomisation method was applied to reconstruct potential
biomes and forest successional stages. Mean annual precipitation, mean
annual potential evapotranspiration and an index of moisture availability
were reconstructed using modern analogues and an artificial neural network
technique. The results show a dense forested environment around Lake Barombi
Mbo of mixed evergreen/semi-deciduous type during the most humid phases
(highest precipitation and lowest evapotranspiration), but with a more
pronounced semi-deciduous type from ca. 6500 cal yr BP to the present day,
related to increased seasonality. This forest displays a mature character
until ca. 2800 cal yr BP, then becomes of secondary type during the last
millennium, probably due to increased human activity. Two episodes of forest
fragmentation are shown, which are synchronous with the lowest reconstructed
precipitation and highest potential evapotranspiration values. The first of
these occurs during the LGM, and the second one from ca. 3000 to ca. 1200 cal yr BP, mainly linked to high precipitation seasonality. Savanna were,
however, never extensive within the Barombi Mbo basin, existing instead
inside the forest in form of savanna patches. The climate reconstructions at
Lake Barombi Mbo suggest that the artificial neural networks technique would
be more reliable in this region, although the annual precipitation values
are likely under-estimated through the whole sequence. |
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