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Titel |
Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change? |
VerfasserIn |
A. Ngomanda, A. Chepstow-Lusty, M. Makaya, C. Favier, P. Schevin, J. Maley, M. Fontugne, R. Oslisly, D. Jolly |
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 ; 5, no. 4 ; Nr. 5, no. 4 (2009-10-26), S.647-659 |
Datensatznummer |
250002694
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Publikation (Nr.) |
copernicus.org/cp-5-647-2009.pdf |
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Zusammenfassung |
Past vegetation and climate changes reconstructed using two pollen records
from Lakes Maridor and Nguène, located in the coastal savannas and
inland rainforest of Gabon, respectively, provide new insights into the
environmental history of western equatorial African rainforests during the
last 4500 cal yr BP. These pollen records indicate that the coastal savannas
of western equatorial Africa did not exist during the mid-Holocene and
instead the region was covered by evergreen rainforests. From ca.
4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the
expansion of semi-deciduous rainforest, occurred synchronously with
grassland colonisation in the coastal region of Gabon. The contraction of
moist evergreen rainforest and the establishment of coastal savannas in
Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked
reduction in evergreen rainforest and subsequent savanna expansion was
followed from 2700 cal yr BP by the colonization of secondary forests
dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae). A return to wetter
climatic conditions from about 1400 cal yr BP led to the renewed spread of
evergreen rainforest inland, whereas a forest-savanna mosaic still persists
in the coastal region. There is no evidence to suggest that the major
environmental changes observed were driven by human impact. |
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