Climatic control of blanket mire development at Kentra Moss, north‐west Scotland

Abstract

Summary1 Four peat cores were collected from Kentra Moss, north-west Scotland, and analysed for botanical macrofossils and peat humi®cation. The pollen record was used as a template for the identi®cation of synchronous levels between cores. 2 A non-random pattern of change in bryophyte macrofossils and humi®cation was simultaneous between all four cores. Stratigraphic changes occurred independently of human land-use and were best interpreted as palaeoclimatic events. Remains of Racomitrium lanuginosum and Sphagnum papillosum, in conjunction with changes in peat humi®cation, provided the clearest indication of past increases in climatic wetness (`wetshifts') to impact upon mire hydrology and ecology. 3 Eight wetshifts were identi®ed and radiocarbon-dated, beginning at c. 3250, 2550, 2150, 1400, 1150, 875, 600 and 325 calibrated years BP (cal. BP). Seven of these wetshifts match closely with palaeoclimatic events from a range of mires previously examined in Britain and Ireland. We suggest that blanket mires may provide the best source of decade-to century-scale palaeoclimatic information in oceanic north-west Europe. 4 The proxy-climatic evidence indicates that: (i) the extinction of Sphagnum imbricatum at Kentra Moss (at c. 1400 cal. BP) was caused by an increase in climatic and mire surface wetness, when it was replaced ®rst by Racomitrium lanuginosum and then by Sphagnum papillosum; and (ii) that increased climatic wetness and human land-use were responsible for the shift from an early minerotrophic peatland to ombrotrophic blanket mire at c. 4070 cal. BP. 5 Given the evidence for a prevailing climatic e ect on the development of Kentra Moss, the e ect of human-induced global warming on Britain's blanket mire resource will probably be signi®cant. British blanket mires have international conservation status, and future changes in their ecology will challenge conservationists, academics and politicians.

Bioclimatic envelope model of climate change impacts on blanket peatland distribution in Great Britain

“…To a certain extent, this may explain why the predicted distribution of blanket peatlands from the model matches the observed distribution so closely. These ecosystems are very sensitive even to decadal variability in climate (Ellis & Tallis 2000). It is therefore likely that the present distribution of blanket peatlands in Great Britain is close to equilibrium with the current climate, notwithstanding anthropogenic disturbances such as drainage and other land-use changes.…”

“…However, blanket peatlands are special ecosystems in that they are ombrotrophic mires dependent on high water table levels, which are maintained solely by the right climatic conditions, i.e. high precipitation and low temperature, and as such, they are highly vulnerable to climate change (Gignac et al 1998, Ellis & Tallis 2000.…”

Atlantic to Urals – the Holocene climatic record of Mid-Latitude Europe

“…Due to a number of mistaken ideas on bog growth the potential of the record was not properly exploited until the work of Aaby (1976), van Geel (1978 and Barber (1981). Over the last two decades the work of Dupont (1986), Svensson (1988aSvensson ( , 1988b, Chambers (1991, 1995), Barber et al (1994), Chambers et al (1997), van Geel et al (1996, Mauquoy and Barber (1999), Ellis and Tallis (2000) and Chiverrell (2001), amongst others, has shown the important role of climate as an allogenic forcing factor in ombrotrophic (rain-fed) bog growth and therefore of peat stratigraphy as a proxy climate record. Recent developments of more quantified analyses (Barber et al 1994;Blackford and Chambers 1993;Charman et al 1999;Barber et al 2000) have revived the usefulness of the peat archive, and correlations between bog surface wetness (BSW) and chironomid-derived temperature reconstructions from a lowland lake support the hypothesis that changes in BSW are driven primarily by summer temperature .…”

Peat decomposition – shaping factors, significance in environmental studies and methods of determination; a literature review

“…Lowland raised bogs occur in central and southern taiga and the cool, humid zone of mixed forests. Large complexes of them most often occupy spacious seaside valleys of the last glaciations in the region of The most comprehensive palaeoclimatic research based on the degree of peat decomposition was conducted in the British Isles and in Norway (Barber, 1981;Blackford & Chambers, 1991;Nilssen & Vorren, 1991;Blackford & Chambers, 1993;Barber et al, 1998;Blackford, 1998;Ellis & Tallis, 2000;Chiverrell, 2001;Mauquoy & Barber, 2002). The British most often used the method of chemical extraction of humic acids in NaOH, and then measured the light absorbance of the solution using a colorimeter filter, wavelength 540 nm.…”