Late pleistocene and holocene vegetation history of the Bale mountains, Ethiopia

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dc.contributor.author Lezine, A. -. M.
dc.contributor.author Umer, M.
dc.contributor.author Bonnefille, R.
dc.contributor.author Lamb, Henry F.
dc.date.accessioned 2008-12-15T16:41:01Z
dc.date.available 2008-12-15T16:41:01Z
dc.date.issued 2007-09
dc.identifier.citation Lezine , A M , Umer , M , Bonnefille , R & Lamb , H F 2007 , ' Late pleistocene and holocene vegetation history of the Bale mountains, Ethiopia ' Quaternary Science Reviews , vol 26 , no. 17-18 , pp. 2229-2246 . , 10.1016/j.quascirev.2007.05.004 en
dc.identifier.issn 0277-3791
dc.identifier.other PURE: 94751
dc.identifier.other dspace: 2160/1663
dc.identifier.uri http://hdl.handle.net/2160/1663
dc.description Lamb, Henry, Umer, M., Bonnefille, R., Lezine, A-M., (2007) 'Late pleistocene and holocene vegetation history of the Bale mountains, Ethiopia', Quaternary Science Reviews 26(17-18) pp.2229-2246 RAE2008 en
dc.description.abstract A sediment core recovered from Garba Guracha, a glacial lake at 3950 m altitude in the Bale Mountains of Ethiopia, at the boundary of the Ericaceous and Afroalpine vegetation belts, provides a 16,700-year pollen record of vegetation response to climatic change. The earliest vegetation recorded was sparse and composed mainly of grasses, Amaranthaceae–Chenopodiaceae and Artemisia, indicating an arid climate. At 13,400 cal BP, Amaranthaceae–Chenopodiaceae pollen declined sharply and Cyperaceae increased, suggesting a change to moister conditions. The Younger Dryas interval is represented by a small increase in Artemisia and reduced Cyperaceae, indicating aridity. Just after the start of the Holocene (11,200 cal BP), the upper altitudinal limit of the Ericaceous belt rose, and woody Ericaceous vegetation extended across the Sanetti plateau, in response to increased moisture and temperature. The marked change from clastic to organic lake sedimentation at this time reflects the increase in woody vegetation cover in the lake catchment, accompanied by soil stabilisation, and increased leaf litter and soil humus content. From about 6000 cal BP, and especially after 4500 cal BP, mid-altitude dry Afromontane Juniper–Podocarpus forests developed on the northern slopes of the mountains in response to reduced rainfall in a shortened wet season. Erica shrub and forest decreased in area and altitude, and the Afroalpine ecosystem expanded on the plateau. Podocarpus declined from about 2000 cal BP, as Juniperus increased to its present dominance at 2500–3300 m altitude. Human impact on the high-altitude Afroalpine and Ericaceous vegetation has been relatively minor, confirming that the endemic biodiversity of the Ethiopian mountains is a legacy of natural Holocene vegetation change, following repeated expansion and contraction of the upland ecosystems during the Quaternary. en
dc.format.extent 18 en
dc.language.iso eng
dc.relation.ispartof Quaternary Science Reviews en
dc.title Late pleistocene and holocene vegetation history of the Bale mountains, Ethiopia en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1016/j.quascirev.2007.05.004
dc.contributor.institution Institute of Geography & Earth Sciences en
dc.contributor.institution Quaternary Environmental Change Group en
dc.description.status Peer reviewed en


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