Abstract/Summary

This thesis presents the results of an investigation of the relationships between peatland hydrology, climate change and human activity in the raised bogs of Ireland. In recent decades raised bogs have been shown to be valuable terrestrial archives of both climate change and archaeological activity for the Middle and Late Holocene, revealing evidence for significant centennial scale climate variability and abrupt climate events. However, recent compilations of palaeohydrological records from such sites have revealed evidence for significant inter-site (potentially autogenic) variability, particularly at the decadal to centennial scales thought to have had the most significant impact on human societies. Whilst recent investigations have revealed some evidence for a relationship between peatland hydrology and human activity at individual sites, broader patterns have been inconclusive, leading to the conclusion that the timing and extent of peatland use was not climatically-determined. The palaeohydrology of ten raised bogs in central Ireland has been reconstructed using plant macrofossil analysis, providing a reconstruction of changes in bog surface wetness (BSW) (driven by summer precipitation and temperature). These palaeohydrological records have been compared to site-specific and broader Ireland-wide archaeological datasets in order to examine the evidence for a predictable, consistent relationship between human activity and BSW. The palaeohydrological records are indicative of a combination of both local variability and climatic forcing; however, using the 'time-window' approach the data has provided evidence for regional transitions to wetter conditions indicative of climate forcing at ca. 3400, 2800, 1200 and 350 cal BP. Comparison of the palaeohydrological and archaeological datasets indicates that at individual sites, human activity was more likely to occur in drier bogs. However, no clear linear relationship between climate change and human activity at the broader regional/sub-regional scales could be identified. The apparent contradictions between the interpretation of the data at regional/sub-regional and local scales highlight the issues of chronological uncertainty and local variability in both archaeological and palaeohydrological records. It was therefore concluded that investigations of human-environment interactions should examine these relationships on a site-by-site basis, in order to provide a more detailed understanding of the complex relationships between human activity in peatlands, local environmental conditions and regional climate change.