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HOLOCENE ENVIRONMENTAL AND HUMAN INTERACTIONS IN EAST AFRICA

Githumbi, Esther Nyambura (2017) HOLOCENE ENVIRONMENTAL AND HUMAN INTERACTIONS IN EAST AFRICA. PhD thesis, University of York.

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Abstract

A multi-proxy approach analysing pollen, macro-charcoal, sediment characterisation and elemental profiles was used to develop palaeoecological records and reveal environmental changes since the late Pleistocene- Holocene transition period from Mau Forest and since the mid-Holocene from Amboseli. Mau Forest was characterised by diverse Afromontane forest taxa between �16,000 cal yr BP and �13,000 cal yr BP which decreased during the Younger Dryas. During the early Holocene, there was a slight increase in montane tree taxa and the main vegetation change noted during the Holocene was the increase in woody shrubs and herbs. The pollen, sediment characterisation and elemental profiles revealed that climatic variability was the main driver of forest composition change and periods of aridity and wetness were identified at�15,000, �13,400, �12,000 and �1200 cal yr BP where there was increased organic matter, sand, magnetic susceptibility with peaks in detrital elements suggesting periods of wetness. Four new Amboseli records dating from the mid Holocene (�5000 cal yr BP) revealed a predominantly dry environment characterised by localised wet and dry phases and fire activity. The spatial differences observed from the Amboseli records are attributed to hydrological variance as the swamps are all fed by ground water and the differential use by humans and wildlife. Kimana, Enkongu and Esambu swamps are Cyperaceae dominated; the pollen records indicate that Amboseli is a grassland savannah dominated by Poaceae, Acacia, Commiphora and Euphorbia. The pollen composition and abundance and charcoal concentration levels vary between the four Amboseli sites indicating localised drivers and controls of fire at each site. This long-term information is useful in the development of ecosystem management policies which are constantly being updated due to the evolving pressures caused by increasing populations and changing land use around the two ecosystems.

Item Type: Thesis (PhD)
Related URLs:
Academic Units: The University of York > Environment (York)
Identification Number/EthosID: uk.bl.ethos.736597
Depositing User: Miss Esther Nyambura Githumbi
Date Deposited: 07 Mar 2018 13:43
Last Modified: 24 Jul 2018 15:24
URI: http://etheses.whiterose.ac.uk/id/eprint/19515

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