Palaeohydrological records derived from testate amoebae analysis from peatlands in northern England: within-site variability, between-site comparability and palaeoclimatic implications

Testate amoebae analysis was undertaken on eight cores from three mires within a restricted geographical area of northern England. This was used to assess, first, the amount of autogenically produced variability in palaeohydrological records from ombrotrophic mires, and, second, to determine whether a palaeoclimatic signal can be derived from testate amoebae analysis from peatlands. Past mean annual water tables were reconstructed by calibrating the testate amoebae record with an existing transfer function. There is a good degree of replicability between the water table reconstructions for the upper peats within each site (especially since cal. AD 600) and the magnitude and timing of most changes are similar. The results show that autogenic factors have a relatively minor control on palaeohydrological records from ombrotrophic peatlands, even for marginal locations where these effects should be greatest. Records from the centres of peatlands are compared to assess the replicability of hydrological changes between the sites to determine which of these changes are attributable to climate. The major fluctuations are well replicated in all central cores, especially for the last 2000 years, suggesting that these shifts are climatically forced and that there is an increasing climatic influence through time, even at the valley mire site. Comparisons with other proxy climatic records suggest that mire surface wetness changes occurred in concert across a broad region of northern England and southern Scotland during at least the last 2000 years.