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Past Environmental Change On The Eastern Andean Flank, Ecuador

Keen, Hayley Frances (2015). Past Environmental Change On The Eastern Andean Flank, Ecuador. PhD thesis The Open University.

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Abstract

The eastern Andean flank of Ecuador (EAF) contains some of the world’s most biodiverse ecosystems. Andean montane forests are threatened due to anthropogenic pressures and both current and projected climate change. This thesis examines the palaeoecological history of two stratigraphic sequences (Mera Tigre West [MTW] and Mera Tigre East [MTE]) obtained from the Ecuadorian modern lower montane forest. The sediments preserved were analysed using eight analytical techniques, allowing an insight into the ecosystem’s potential response to projected changes derived from their past responses. Palaeoecological studies on the EAF are rare, and those that do exist are debated relating to: i) the inference of robust ecological data from pollen records in floristically diverse locations, and ii) the past source area of sediments preserved in fluvially exposed sequences, potentially leading to contamination with older material.

A statistical sub-sampling tool was developed (debate i), capable of producing statistically robust count sizes for each pollen sample; MTW and MTE count sizes ranged from 196-982 showing the diversity within sequences. The depositional environment of MTE was analysed, investigating sediment provenance throughout (debate ii). Results found that large scale volcanic events were critical in the preservation of the sediments, whereas fluvial influence caused a regional sediment source area in the upper stratigraphy, impacting on the palynological interpretation of MTE. Pollen records demonstrated the presence of a diverse vegetation community with no modern analogue at MTE (abundant taxa (>15 %): Hedyosmum, Wettinia, Ilex) and upper montane forest at MTW (Alnus, Hedyosmum, Podocarpus). Fire was not the main driver for the vegetation reassortment at either site (MTW correlation coefficient: -0.37, MTE: 0.16). The two sites have demonstrated the EAF plays host to floristically dynamic ecosystems, susceptible to drivers of change (fire and landscape) and should be considered when predicting the montane forests’ future response to environmental change.

Item Type: Thesis (PhD)
Copyright Holders: 2015 The Author
Project Funding Details:
Funded Project NameProject IDFunding Body
NERCNot SetNot Set
The Open University (OU)Not SetNot Set
Keywords: forest plants; mountain plants; forest ecology; mountain ecology; rain forest ecology; biodiversity; climatic changes; palaeocology
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Item ID: 52938
Depositing User: Hayley Keen
Date Deposited: 25 Jan 2018 10:57
Last Modified: 04 Jul 2019 07:13
URI: http://oro.open.ac.uk/id/eprint/52938
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