A 7500-year peat-based palaeoclimatic reconstruction and evidence for an 1100-year cyclicity in bog surface wetness from Temple Hill Moss, Pentland Hills, southeast Scotland

Knaap

et al. 2010

J Quaternary Science

We present the first testate amoeba-based palaeohydrological reconstruction from the Swiss Alps, and the first depth to the water table (DWT) calibration dataset for this region. Compared to existing models, our new calibration dataset performs well (RMSEP ¼ 4.88), despite the length of the water table gradient covered (53 cm). The present-day topography and vegetation of the study mire Mauntschas suggest that it is partly ombrotrophic (large Sphagnum fuscum hummocks, one of which was the coring site) but mostly under the minerotrophic influence of springs in the mire and runoff from the surrounding area. Ombrotrophic Sphagnum fuscum hummocks developed at the sampling site only during the last 50 years, when testate amoebae indicate a shift towards dry and/or acid conditions. Prior to AD 1950 the water table was much higher, suggesting that the influence of the mineral-rich water prevented the development of ombrotrophic hummocks. The reconstructed DWT correlated with Pinus cembra pollen accumulation rates, suggesting that testate amoebae living on the mire and P. cembra growing outside of it partly respond to the same factor(s). Finally, temperature trends from the nearby meteorological station paralleled trends in reconstructed DWT. However, contrary to other studies made on raised bogs of northwestern Europe, the highest correlation was observed for winter temperature, despite the fact that testate amoebae would more logically respond to moisture conditions during the growing season. The observed correlation with winter temperature might reflect a control of winter severity on surface moisture during at least the first part of the growing season, through snow melt and soil frost phenomena influencing run-off. More ecohydrological work on subalpine mires is needed to understand the relationships between climate, testate amoebae and peatland development.

Section: Surface Wetness and Climatementioning

confidence: 98%

A near‐annual palaeohydrological study based on testate amoebae from a sub‐alpine mire: surface wetness and the role of climate during the instrumental period

Knaap

et al. 2010

J Quaternary Science

Palaeogeography, Palaeoclimatology, Palaeoecology

“…Barber and Langdon, 2007;Blundell and Barber, 2005;Langdon et al, 2003). The hydrological data generated for this taxon here are much needed in the British training set as the NI and ACCROTELM water table depth optima-tolerance figures are dissimilar which is likely due to localised site variance.…”

Section: Improving Analoguesmentioning

confidence: 99%

Comparing regional and supra-regional transfer functions for palaeohydrological reconstruction from Holocene peatlands

Turner

Swindles

Charman

et al. 2013

Testate amoebae-based transfer functions are commonly used in peatland palaeoclimate studies. These models have been developed in several regions of the world and are sometimes used for palaeohydrological reconstruction from fossil data in locations where no transfer functions exist. Limitations of this approach may include missing modern analogues and problems associated with site-specific or regional factors in testate amoebae ecology and biogeography. This study presents new testate amoebae-hydrology transfer functions based on data from six peatlands in Northern England. Transfer functions were generated for water table depth and moisture content using weighted averaging tolerance downweighted regression with inverse deshrinking and model performance was assessed using leave-one-out (jacknifing) cross-validation.To examine the robustness of applying transfer functions extra-regionally, we performed a number of spatially independent cross-validation (SICV) tests using contemporary testate amoebae and environmental data from established Northern Ireland and European transfer functions. Inferred water table depths were consistent with observed values in terms of position along the hydrological gradient, however magnitudes varied. We then applied the three independent transfer functions to fossil data from a peatland in Northern England to compare the reconstructions. The results show that the direction of the reconstructions is consistent in terms of wet/dry shifts.However, variation in the magnitudes of the reconstructed water tables is apparent.This probably reflects the sampling regime, including temporal/seasonal effects, and differences in testate amoebae ecology between regions and individual sites.

“…Sites plotted are not exhaustive, but illustrate the extent of, ash plume fallout for the various volcanic centres. Icelandic data from: Bergman et al, 2004;Bjö rck and Wastegard, 1999;Boygle, 1994;Caseldine et al, 1998;Chambers et al, 2004;Dugmore and Newton, 1997;Dugmore et al, 1995;Dugmore et al, 1992;Eiriksson et al, 2000;Haflidason et al, 2000;Hall and Pilcher, 2002;Hunt, 2004;Langdon et al, 2003;Langdon and Barber, 2001;Litt et al, 2001;Mortensen et al, 2005;Pilcher et al, 1995;Plunckett et al, 2004;Turney et al, 1997;van den Bogaard and Schmincke, 2002;Wastegard et al, 2000Wastegard et al, , 2001. Eifel data from: Litt et al, 2001;Moscariello and Costa, 1997;van den Bogaard and Schmincke, 1985;Vanniere et al, 2004.…”

Section: The Timing Of Human Expansion In Northwest Europe and Of Abrmentioning

confidence: 99%

The chronology of abrupt climate change and Late Upper Palaeolithic human adaptation in Europe

Blockley

Donahue

et al. 2006

J Quaternary Science

This paper addresses the possible connections between the onset of human expansion in Europe following the Last Glacial Maximum, and the timing of abrupt climate warming at the onset of the Lateglacial (Bö lling/Allerød) Interstadial. There are opposing views as to whether or not human populations and activities were directly 'forced' by climate change, based on different comparisons between archaeological and environmental data. We review the geochronological assumptions and approaches on which data comparisons have been attempted in the past, and argue that the uncertainties presently associated with age models based on calibrated radiocarbon dates preclude robust testing of the competing models, particularly when comparing the data to non-radiocarbonbased timescales such as the Greenland ice core records. The paper concludes with some suggestions as to the steps that will be necessary if more robust tests of the models are to be developed in the future.