past projects

Holocene environmental change in the Burren – Mullagh Mór and the Burren Uplands

Ingo Feeser and Michael O’Connell

The major part of the study was centred on Loch Gealáin, the lake-turlough system in at Mullach Mór, Burren National Park. Multi-proxy investigations, including pollen and macrofossil analyses, etc. were carried out on cores from Loch Gealáin. The results facilitated detailed reconstruction of vegetation dynamics and farming history as well as providing new insights into changes in the local hydrological regime and development of the turlough system at Loch Gealáin.

Investigations carried out in the Burren uplands included pollen and macrofossil analyses, and loss-on–ignition measurements of short peat monoliths from Calluna-dominated heath on the Cappanawalla and Gortaclare uplands. Special attention was paid to coprophilous (dung) fungal spores (CFS) as indicators of local grazing. New insights were also gained regarding the history of the Dryas-Arctostaphylos uva-ursi (mountain avens-alpine bearberry) heaths which are of exceptional biodiversity and conservation value.

Sediments recovered from grykes provided evidence for soil erosion which continued to be important in the Burren uplands until well into medieval times.

Since completing his PhD Ingo Feeser has returned to Germany to take up a postdoctoral research position in palaeoecology in the University of Kiel (CAU) within the Centre of Excellence for Landscape Studies.

References Feeser, I. and O’Connell, M. 2009. Fresh insights into long-term changes in flora, vegetation, land use and soil erosion in the karstic environment of the Burren, western Ireland. Journal of Ecology 97, 1083–1100

Feeser, I. and O’Connell, M. 2010. Late Holocene land-use and vegetation dynamics in an upland karst region based on pollen and coprophilous fungal spore analyses: an example from the Burren, western Ireland. Vegetation History and Archaeobotany. Published online DOI 10.1007/s00334-009-0235-5, Jan 2010; 18 pp.

Photographs of monoliths and the uplands at Cappanawalla, Gortaclare and Lios Lairthín Mór.

A Monolith CPW1 (scale division = 2 cm);

B Removing monolith CPW1 (view to SW, 21/08/2006);

C Cappanawalla uplands with cattle, a typical Burren upland winter scene (view towards Slieve Elva, 24/03/2007);

D Tumble wall (no longer functional) meets a relatively recent wall (south of CPW1);

E Monolith GTC7 (scale division = 2 cm);

F Gortaclare uplands at sampling site where GTC7 was taken (Calluna-dominated heath and stone-wall windbreak in the background, 12/05/2006);

G Sesleria grasslands on Gortaclare. View north-east towards summit of Slievecarran; a low mound wall runs diagonally in the foreground and in mid-view there is a single wall with a wind-bent Crataegus monogyna bush (21/09/2008);

H Lios Lairthín Mór. View to north from top of peat mound where LLM II was taken (8/06/2007). The bog borders directly onto large stone-wall enclosed fields with species-rich Sesleria pastures and wind-bent Crataegus bushes

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Palaeoenvironmental investigations at Kilbegly, Co. Roscommon, the site of a horizontal watermill (M6)

Annette Overland and Michael O’Connell

Pollen analytical investigations by Anette Overland of short monoliths, moss samples (from a fulacht fia and from beneath the mill flume) and a peat core have provided insights into the local environment at Kilbegly from the Bronze Age to high medieval times. The evidence for farming in Ireland (with particular reference to mid-western Ireland) is reviewed.

Publications
Overland, A. and O'Connell, M. 2010. New insights into late Holocene farming and woodland dynamics in western Ireland with particular reference to the early medieval horizontal watermill at Kilbegly, Co. Roscommon. Review of Palaeobotany and Palynology

Overland, A. and O'Connell, M. 2013. Reconstruction of the past environment at Kilbegly: palaeoecological investigations. In: Jackman, N., Moore, C., Rynne, C. and Devane, C. (eds). The mill at Kilbegly. Archaeological Investigation of an early medieval horizontal mill and other excavations on the N6 Ballinasloe to Athlone road scheme. National Roads Authority Archaeology Scheme Monographs 12. The National Roads Authority, Dublin.

1. Overview towards south-west of the horizontal-mill site during excavation (Kilbegly 2; 24/07/2007). A recent drain runs diagonally across the photograph. An arrow points to a dot that marks the location of core KLB-U2. A mire once occupied the basin, including the area with forestry in the background.

2. Sampling peat (mainly mosses) from beneath the flume. The flume and part of undercroft are shown (view from east side; 22/08/2007)

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Farming and woodland dynamics in north Sligo during the Holocene based on lake-sediment investigations

Beatrice Ghilardi and Michael O’Connell

Detailed pollen-analytical investigations were carried out on lake sediments cores from two lakes, Lough Dargan and Cooney Lough, in north County Sligo close to the Cúil Irra peninsula. North Sligo was chosen as a study area on account of the wealth of archaeological evidence relating especially to the Neolithic. The Cúil Irra peninsula has the largest passage tomb cemetery of Ireland, namely Carrowmore and also the archaeologically rich and conspicuous mountain, Knocknarea. The investigations aimed to reconstruct farming activity, woodland dynamics and land-use, based mainly on detailed pollen analysis. Macrofossil analysis, magnetic susceptibility and loss-on-ignition measurements were also carried out. Results from the two high resolution pollen diagrams show that tall canopy woodland characterised the first half of the Holocene  with the earliest indication of farming coinciding with the Elm Decline (ca 3750 BC).

Selected Publications

Ghilardi, B. and O’Connell, M. 2013. Early Holocene vegetation and climate dynamics with particular reference to the 8.2 ka event: pollen and macrofossil evidence from a small lake in western Ireland. Vegetation History and Archaeobotany, 22, 99–114. [DOI: 10.1007/s00334-012-0367-x]

Taylor, K.J., A.P. Potito, D.W. Beilman, B. Ghilardi, and M. O’Connell. (2013). Palaeolimnological impacts of early prehistoric farming at Lough Dargan, County Sligo, Ireland. Journal of Archaeological Science 40: 3212-3221.

Ghilardi, B. and O’Connell, M. 2012. Fine-resolution pollen-analytical study of Holocene woodland dynamics and land use in north Sligo, Ireland. Boreas, DOI: 10.1111/j.1502-3885.2012.00292.x

M O'Connell, B Ghilardi, L Morrison (2013) A 7000-year record of environmental change, including early farming impact, based on lake-sediment geochemistry and pollen data from County Sligo, western Ireland Quaternary Research 81 (DOI: 10.1016/j.yqres.2013.10.004), 35-49

Figure S1. Lake-sediment coring (core CNY1) in Cooney Lough, by a coring team from PRU, NUIG and Christian-Albrechts-Universität (CAU), Kiel. Ulex europaeus (furze) is flowering on steep ground in the foreground. The background, to the north, is dominated by Knocknarea withits distinctive shape and large cairn (Maeve’s tomb) on top that probably includes a passage tomb. Carrowmore, the largest megalithic cemetery in Europe, lies at the foot of Knocknarea. Photo: MO’C; 28/04/2010.

20th Century human and climate impacts on a large mountain lake in SW China

A.P. Potito, X. Guo, L. Luo, D. Beilman

Subfossil chironomid and sediment geochemistry data from Lugu Lake, a large high-elevation lake in southwest China, were used to assess the influences of climate warming and direct human impacts on the lake through time. A 95-year-long sediment record was recovered from the lake. The four prominent environmental controls on the chironomid community were summer air temperature, organic matter C:N ratio, dry mass accumulation rate (DMAR), and total nitrogen. Lake productivity proved to be the most important controlling factor through time. However, C:N and summer air temperature were highly co-linear, possibly due to temperature directly impacting lake productivity (and thus C:N ratios) through increased stratification and a longer growing season. PCA Axis 1 scores were a strong predictor of summer temperatures even after DMAR was factored out to account for direct human influences. The strong temperature-chironomid relationship over the last 50 years could be due to the lake becoming more responsive to climate warming after cultural eutrophication of the 1950s, as lakes with higher nutrient loads are shown to be more responsive to the effects of climate warming. This project was funded through the Sichuan University Open Research Fund.

Guo, X., A.P. Potito, L. Luo, and D.W. Beilman (2013) Twentieth century human and climate impacts on a large mountain lake in southwest China. Hydrobiologia 718: 189-206.

Figures: 1) Comparison of chironomid-predicted summer temperatures with measured temperatures, 2) Lugu Lake sediment core, 3) Lugu Lake

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Climate and human influences on chironomid communities in western Ireland

(M. McKeown, A.P. Potito)

Freshwater lakes are widely regarded as excellent archives of past environments, and chironomid larvae contained within the lakes are extremely sensitive to limnological change. This study tested the sensitivity of chironomids in western Ireland to recent temperature and land-use change, and assessed their applicability as palaeotemperature indicators across timescales. This project was funded through Whitaker Institute, Irish Quaternary Association and the Royal Irish Academy.

McKeown, M., A.P. Potito, and K.R. Hickey (2012) The long-term temperature record from Markree Observatory, County Sligo from 1842-2011. Irish Geography 45: 257-282.

Figures: 1) Sectioning a short core at Lough Meenagraun, 2) Predicted vs measured temperature from two lakes in northwest Ireland

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Evaluating the dendroclimatological potential of Taxus baccata (yew) in southwest Ireland

S. Galvin, A.P. Potito, K. Hickey

Tree-ring research in Ireland has typically been dominated by Quercus species, particularly Quercus petraea and Quercus robur. Recent years have seen a greater focus on multi-species reconstructions in Ireland but, due to difficulties with the hardness of the wood, missing/pinched rings and fused stems, Taxus baccata has not been included in these investigations. Despite these difficulties, a 31-tree, 204-year T. baccata chronology was successfully constructed from Killarney National Park, southwest Ireland. The chronology exhibits promising dendroclimatological potential, with climatic responsiveness equivalent to that of the other major Irish tree taxa, including Quercus. The long-lived nature of T. baccata, the exceptional preservation of wood and rings in this hard softwood species, as well as its prominence in Irish archaeology, all point to the potential to expand this chronology both spatially and temporally, and demonstrate T. baccata's potential in multi-site and multi-species tree-ring studies in the region.

Galvin, S.A., A.P. Potito and K.R. Hickey (2014) Evaluating the dendroclimatological potential of Taxus baccata (yew) in southwest Ireland. Dendrochronologia 32: 144-152.

Figure: Coring a yew tree in Reenadinna Wood, Killarney National Park, SW Ireland.

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