Littleton Bog in Ireland provides a record of climate and vegetation changes over the Holocene. Analysis using plant macrofossils, pollen, testate amoebae, and stable isotopes show periods where the bog was wetter and drier, linked to changes in the North Atlantic. Two main phases of human activity are also recorded, with earlier trackways constructed of oak planks and later of roundwood, adapting to climate-driven changes in bog conditions.

1. © University of Reading 2008 www.reading.ac.uk
UKAS 2011
08 July 2015
Holocene Hydrological and Vegetation Changes in
Ombrotrophic Bogs in Central Ireland: Implications
for our Understanding of Climate History and
Human Activities
Young, D., Stastney, P., Black, S., Branch, N., Pritchard, O., McCarroll, J. and Whitaker, J.

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Introduction
• Littleton Bog, Co.
Tipperary
• Milled peat production
bog
• Formerly an
ombrotrophic, raised bog

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Littleton Bog
• Type site for the
Holocene
vegetation history
of Ireland (Mitchell,
1956; 1965)
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Raised peat bogs as archives
• Sensitive to changes in
precipitation-evapotranspiration
balance since they are
ombrotrophic, or literally ‘cloud-
fed’ systems free from the
influence of groundwater
• So a record of bog surface wetness
can be a record of climate
(precipitation and temperature)
change
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Archaeology
Plank trackway
2972-2789 cal BP
Brushwood trackway
1865-1596 cal BP

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Methods
• Loss-on-ignition
• Humification
• Radiocarbon dating
• Plant macrofossils
• Pollen
• Testate amoebae
• Oxygen, carbon and hydrogen isotopes
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ca. 5 yr/cm
ca. 42 yr/cm

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Results: Plant Macrofossils
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• Oligotrophic transitional bog during LTN 1, LTN 2
• Drier raised mire during LTN 3; Increasingly wet during
LTN 4; drier in LTN 5; increased wetness during LTN 6

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Results: Pollen
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• Stable bog surface during pollen zone 1
• Hazel/bog myrtle declines during 2a-2b, grasses/Sphagnum
increase
• Sphagnum/grasses decline, increased heath, pine during 2c

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Results: Testate Amoebae
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Reconstructed water table curve produced using Charman et al. (2007) transfer
function, with thanks to Dan Charman, University of Exeter.

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Results: Stable Isotopes
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Composite diagram
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Medieval Warm Period
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Medieval Warm Period
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Bond events
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Bond events and trackways
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Dated archaeology at Littleton
• 13 structures dated:
– 9 trackways
– 4 platforms
• Apparently 2 main
phases:
– 3 earlier structures are
all constructed from
Oak planks
– Later structures
constructed from
roundwood.
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Dated structures at Littleton
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Conclusions
• Multi-proxy analysis from Littleton Bog shows that
evidence for climatic forcing of changes in the ecology of
the bog.
• There is a link between changes in the circulation in the
North Atlantic, and changes in effective precipitation at
Littleton.
• These changes may have driven a series of bog bursts.
• Human activity on the bog adapted to these changes.
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