The identification of late-Holocene bog bursts at Littleton Bog, Ireland: Ecohydrological changes display complex climatic and non-climatic drivers

Abstract

In order to clearly understand the response of raised mires to past climate change, it is important to consider the full range of drivers and responses of these ecohydrological archives. To this end, a high-resolution ecohydrological record from Littleton Bog, Co. Tipperary, Ireland, was generated utilizing a combination of plant macrofossils, testate amoebae and humification analysis. Chronological control for this record was provided by a Bayesian age–depth model based on AMS radiocarbon dates. Testate amoebae–derived reconstructed peatland water tables indicate a series of sudden shifts to dry bog surface conditions at c. 3140, c. 2510 and c. 1540 cal. BP. These events display a distinctive palaeoecological signal and chronological tempo that is best explained as a result of a series of bog burst events and which seem inconsistent with other explanations. The chronological correspondence between the bog bursts at Littleton and a set of similar events at Derryville Bog, c. 5 km to the north, is noted, as is the broad correspondence of these events with wet shifts indicated in regional peatland water table compilations from Britain and Ireland. A range of possible driving mechanisms for these events is proposed, including anthropogenic disturbance of the bog surface, non-linear response to climate forcing, internal bog dynamics, vegetation succession or a combination of factors. We illustrate the need for further multi-proxy investigations to fully understand these phenomena.