Generating multi-proxy Holocene palaeoenvironmental records from blanket peatlands

    Generating multi-proxy Holocene palaeoenvironmental records from blanket peatlands Antony Blundell, Joseph Holden, T. Edward Turner PII: DOI: Reference:

S0031-0182(15)00718-X doi: 10.1016/j.palaeo.2015.11.048 PALAEO 7600

To appear in:

Palaeogeography, Palaeoclimatology, Palaeoecology

Received date: Revised date: Accepted date:

12 May 2015 27 October 2015 30 November 2015

Please cite this article as: Blundell, Antony, Holden, Joseph, Edward Turner, T., Generating multi-proxy Holocene palaeoenvironmental records from blanket peatlands, Palaeogeography, Palaeoclimatology, Palaeoecology (2015), doi: 10.1016/j.palaeo.2015.11.048

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ACCEPTED MANUSCRIPT Generating multi-proxy Holocene palaeoenvironmental records from

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blanket peatlands

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Antony Blundell a

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Joseph Holden a

water@leeds, School of Geography, University of Leeds, Leeds, LS2 9JT, UK.

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a

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T. Edward Turner a

Corresponding author: A. Blundell, School of Geography, University of Leeds, LS2 9JT, UK, +44

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(0)11334 31593, [email protected]

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Abstract

Ombrotrophic peatlands have provided important archives for understanding Holocene

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palaeoenvironmental change. However, records are predominantly from raised bogs due to potential issues regarding preservation of proxy indicators, record length and low temporal resolution in other peat types including blanket bogs. By carrying out peat depth and stratigraphy surveys we demonstrate how blanket peatlands can provide archives capable of providing records that are not reliant on single proxies, as has been often the case in the past, and can provide good resolution records. A record containing humification, testate amoebae and plant macrofossils was derived for the last 3000 years with accumulation rates as high as 8 yrs cm-1 providing favourable temporal resolution, particularly over the last 1500 years. Major changes in proxy indicators reflecting potential changes in water-table depth were often coherent with changes in climate. Human activity also had a major impact on the peatland throughout the record especially in the last

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ACCEPTED MANUSCRIPT 100 years where the influence of wildfire and managed burning, together with an effect of atmospheric pollution, fundamentally changed the state of the peatland.

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Keywords: Blanket bog; peat; Holocene; multi-proxy; palaeoenvironment

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ACCEPTED MANUSCRIPT 1. Introduction Ombrotrophic peatlands have formed an important source of records shaping our understanding of

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palaeoclimate and palaeoenvironmental change over the Holocene epoch (Chambers et al., 2012).

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These peatland systems receive water input predominantly from the atmosphere meaning the

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excess of precipitation over evaporation is the primary control over the water table (Barber, 1993). The majority of palaeoclimate records, especially multi-proxy records, from ombrotrophic peatlands are from raised bogs where the water balance relationship is clear and proxy indicators can be

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employed to reconstruct palaeo water-table changes and hence changes in climate (Langdon et al.,

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2003; Blundell and Barber 2005; Blundell et al., 2008; Mauquoy et al., 2008; Swindles et al., 2009). Blanket peatlands, however, can be much more spatially extensive than raised bogs. In Great Britain blanket bogs cover an estimated 1.4 million ha compared to c. 69,000 ha for raised bogs (Lindsay,

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1995). However, the relationship between climate and water table may be less well established for blanket bogs and there has been a reluctance to employ blanket bogs for palaeoclimate and

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palaeoenvironmental reconstructions. The main reasons for this reticence are concerns around 1) complex topographical patterns across blanket peatlands which mean that locations may have different hydrological contributing areas or different accumulation histories; 2) higher level of

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decomposition in blanket peatlands due to greater topographic drainage and a dominance of sedges leading to poorer preservation of macrofossils (Barber, 1993; Langdon and Barber 2001) and other proxy indicators (Whilmhurst et al., 2003; Chambers et al., 2012); 3) a large range of potential blanket peatland initiation dates (e.g. c. 7500-1000 BP (Tallis, 1991) potentially limiting archive length in the UK), and 4) lower accumulation rates leading to poorer temporal resolution for a given sampling interval.

Raised bogs are a well-defined mesotope (Lindsay, 1995) in the landscape with a convex profile often bordered by a ‘rand’ or slope that separates it from the surrounding ‘lagg’ or fen area where

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ACCEPTED MANUSCRIPT ground water is influential (Charman, 2002). Blanket bogs, in NW Europe, the Atlantic Eastern Seaboard, Patagonia and New Zealand (Gallego-Sala et al., 2013), in contrast, can be more

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hydrologically and spatially diverse often enveloping the underlying regional sloping landscape. Even

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though well-developed blanket peatlands are predominantly rainfed (lacking mineral groundwater),

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different points on the landscape will have different water accumulation catchments delivering flow from upslope which may impact water-tables and the production of overland flow (Holden and Burt, 2003). Blanket peatlands, although often appearing relatively uniform on the surface, can represent

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a complex macrotope within which different mesotopes may be distinguished based on hydromorphology and topography (Lindsay, 1995). Terrestrialisation may have occurred in localised

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wet basins, or peat may have formed directly on shallow slopes leading to highly variable peat depths and ages of initiation over a short distance (Smith and Cloutman, 1988). Hilltops and ridges

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form ‘watershed mires’ where hydrological inputs are predominantly governed by the balance of

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precipitation thus making them more suitable for palaeoclimate reconstruction. ‘Saddle’, ‘spur’ and

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‘valleyside’ mires, although often able to develop ombrotrophy, may be influenced by some mineral groundwater from surrounding slopes as they develop. Peat pipes which are large macropores that can transport of water, sediment and dissolved gases (Holden et al., 2012), may in some

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circumstances impact water-table levels and interfere with the effect of climate as a primary influence on the water table. However, no work in peatlands has yet demonstrated such an effect except where pipes have collapsed and formed gullies (Daniels et al., 2008). Although pipes are found in raised bogs (Ingram, 1983), these features are common in blanket bogs (Holden, 2005) and have been found to be highly dynamic even over short time periods (Holden et al., 2012). Issues of proxy preservation have led palaeo record determinations from blanket peatlands to commonly employ a single proxy; typically humification (Blackford and Chambers, 1995; Tallis, 1995; Chambers, 1997; Anderson et al., 1998; Langdon and Barber, 2001). Differential humification rates, have, however, been cited as a potential problem for blanket peatland studies (Caseldine et al., 2000; Yeloff and Mauquoy, 2006; Hughes et al., 2012). For example, examination of humification 4

ACCEPTED MANUSCRIPT absorption values of fresh vegetation, ‘k values’ (Overbeck et al., 1947), from bogs in Newfoundland by Hughes et al. (2012) revealed a potential difference between species by up to a factor of 19.

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Humification values were subsequently adjusted to provide a ‘k score’ to allow the potential

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contribution of species to be examined; Hughes et al. (2012) suggested that this procedure was not a

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solution but a useful tool for data exploration.

Blanket peatlands often initiate from localised water collecting foci and spread via paludification which may be temporally protracted (Tallis, 1991) resulting in large differences spatially in potential

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archive length. However, if subsurface topography is investigated the development of an area of

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blanket peat can be determined and deeper sections identified to maximise the potential archive recovered. Accumulation levels are also likely to fluctuate due to topography as greater drainage

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will lead to more decay and often favour plants that are less resistant to decay.

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The four key issues above (complex topography, differential humification, late initiation, slow accumulation rates) that have previously been reasons for avoiding blanket bogs as palaeoclimate

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archives may be partially overcome. Careful selection of sampling to account for topographic context could be useful. Spatially-distributed stratigraphic surveys providing information on peat depth and

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underlying topography, together with initial assessments of changes in humification and macrofossil type would permit understanding of the developmental history of a blanket peatland site. With such information the area can be better assessed for its potential as a palaeoenvironmental archive before investing time in more detailed data collection. Use of multi-proxy data collection (Blundell et al., 2005), particularly if some of the proxies are collected at high resolution, may also help us to overcome issues around slow accumulation rates. Here we adopt such an approach and present a 2800 year palaeoenvironmental record from a blanket peat-covered catchment in Northern England. We show that the site has good preservation of proxy indicators for the majority of the record, while for the last 1800 years we determine a temporal resolution (mean of 11.9 yrs cm-1) rivalling those typical of raised bogs.

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2. Site description

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Keighley Moor Reservoir catchment (KMRC) is 1.48 km2, located 3.5 km west of Oakworth

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(53°85’31’’ N, -02°02’13’’ E) in northern England (Figure 1). The site is underlain by geology from the Millstone Grit Group and primarily has a superficial geology of peat as described by the British Geological Survey. The site has been managed for grouse shooting since the 1870s, using controlled

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burning to promote vegetation cover with a high proportion of Calluna vulgaris (heather) of different ages and heights for the rearing of grouse. Cotton grasses Eriophorum vaginatum and E.

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angustifolium are dominant in parts of the catchment. On regions of shallow substrate there is substantial Vaccinium myrtillus. Sphagnum mosses are now rare in the catchment and are

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predominantly S. fallax. Other bryophytes such as Hypnum jutlandicum and Campylopus spp. are

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evident at the site. Two wildfires that are recalled by local land managers have occurred in the last

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century at the site. One wildfire occurred c. 1918 and the other in the 1940s which led to some erosion and loss of peat from parts of the catchment.

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3. Methodology

3.1 Peat depth and stratigraphy Depth of peat was determined using a total of 122 gouge drives across the catchment over seven days within the period of 24/04/2009 to 14/10/2009. Detailed stratigraphic changes were logged for 88 of these cores using the Troels-Smith sediment classification scheme (Troels-Smith 1955). Importantly, the sediment description included estimations of the level of bryophytes and the degree of humification. Initially gouge core drives were executed at a moderate spatial resolution (c. 100-150 m between them) across the catchment (Figure 1). This did not conform rigidly to a grid due the nature of the terrain and location of channels and gullies. Examination of resultant maps of peat

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ACCEPTED MANUSCRIPT depths and estimates of peat humification allowed areas of deep peat (Areas 1-3, Figure 1) with good macrofossil preservation to be determined. Further gouge core drives were then located in one

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of the three areas of deep peat that were identified so as to determine a detailed bathymetry and

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determination of humification in the basin (Figure 1). The location of the core to be used for

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palaeoenvironmental reconstruction was determined based upon these findings in an area of deep peat (Area 1) with good preservation of macrofossils. There was no evidence of peat cutting or artificial drainage near to the coring location. Identifiable sources of water at the coring site are of

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direct precipitation and runoff or through flow from the area upslope at the catchment watershed

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(500 m away), an area where the water input will be primarily atmospheric (Figure 1).

analyses

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3.21 Recovery and sampling

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3.2 Recovery, sampling and analyses of core used for detailed palaeoecological

The core was obtained using a monolith tin from the surface to 50 cm. A 100 cm long by 9 cm wide

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Russian corer was used to obtain cores from 0 - 100 cm and 70 -170 cm. A further narrow width (4 cm) 50 cm long Russian corer was used to sample peat from 145 - 195 cm. Therefore, overlaps of at least 25 cm existed between cores with a complete overlap between the first core and the monolith. The core was subsampled for loss on ignition (LOI), spheroidal carbonaceous particles (SCPs) (both 2 cm3), macrofossils (4 cm3), testate amoebae (2 cm3) and humification analyses. Sampling intervals were every 2 cm throughout for LOI and every 0.5 cm for SCPs from 0 – 20 cm. The main proxies employed to determine palaeo water-table levels, testate amoebae, humification and macrofossils were sampled at 1 cm contiguously from 0 - 50 cm. Testate amoebae and humification sampling resolution from 50 cm depth and below was 2 cm and at 4 cm for macrofossils. LOI (reported as %

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ACCEPTED MANUSCRIPT organic matter) was calculated by determining the loss of mass after exposing dried peat samples to

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550°C for 6 hours (Heiri et al., 2001).

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3.22 Chronology

A chronology for the analysis core was derived from both SCPs and AMS radiocarbon dates. SCPs were prepared and counted using the method detailed by Rose (1990, 1994) with minor

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modifications as used in Blundell et al. (2008). The abundance of SCPs counted at ×400 magnification was expressed as SCPs gDM-1 (number of particles per gram of dry mass of peat). Age

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determinations were based on: 1) the peak and 2) the ‘take off’ point of the characteristic curve produced (Rose et al., 1995). Nine Accelerator Mass Spectrometry (AMS) dates were obtained from

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0 - 174 cm from the master core (Table 1). A single radiocarbon date was also derived for the

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deepest part of Area 1 (Figure 1) to determine the earliest time for peat initiation in that area (Table

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1). Sub-sampled 1 cm³ blocks were washed with deionized water in a 125 µm sieve and Sphagnum leaves, branches or stems were selected and washed and visibly examined in order to minimize any potential contamination. Traces of ericaceous roots were removed to prevent any possible reservoir

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effects as described by Kilian et al. (1995). Bulk samples were used at 140, 154 and 174 cm due to the lack of discernable macrofossils of sufficient mass to provide a selective sample. It is acknowledged that using bulk samples can introduce potential errors as they may contain below ground material such as rootlets that can introduce younger carbon into the sample (Blaauw et al., 2004). Samples were dated via AMS at the CHRONO Laboratory at Queens University Belfast. An age-depth model was produced using the ‘Bacon’ accumulation model (Blaauw and Christen, 2011) in the R program (R Core Team, 2012). This model uses Bayesian statistics to determine Bayesian accumulation histories using radiocarbon dates and prior information. Prior information regarding accumulation rate and its potential to vary (Figure 2 displays parameters used) are accounted for providing potentially more realistic environmentally dependent age-depth models. Calendar 8

ACCEPTED MANUSCRIPT estimated ages from SCPs have also been employed in the model Bacon provides estimates of total chronological error with maximum age probabilities (MAP) for 1 cm intervals. Maximum and

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minimum ages within the modelled age range (MAR) are also provided. Here, as carried out by

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Turner et al. (2014), quoted ages are MAP together with, when required, MAR in subscript text. Due

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to the small depth span of many of the macrofossil and testate amoebae zones the MARs ascribed to their boundaries will overlap as errors associated with radiocarbon dating are often greater than the

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age span of the zone itself.

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3.23 Proxy analyses

Macrofossil analyses were performed using the Quadrat and Leaf method (Barber et al., 1994).

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Nomenclature for Sphagnum mosses follows Daniels and Eddy (1990) and for other vascular plants,

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Stace (1991). A Hydroclimatic Index (HYI) was calculated by weighted averaging ordination after

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Dupont (1986) and Daley and Barber (2012) with each taxa weighted based on its relative position along the water-table gradient. Taxa have been weighted from the wettest (1) to the driest (8) (Sphagnum cuspidatum 1, Sphagnum section Cuspidata 1, Sphagnum papillosum 3, Sphagnum

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magellanicum 3, Sphagnum section Acutifolia 4, monocotelydons 6, Eriophorum vaginatum 6, Unidentified organic matter (UOM) 8, Ericaceae 7, Erica wood 7, Campylopus pyriformis 8)). As part of the macrofossil analysis, charcoal (>125µm) was also recorded as absolute counts and when too numerous as % total macrofossil assemblage. Analyses to determine the degree of humification of the peat were carried out in accordance with methods recommended by Blackford and Chambers (1993). This involved chemical extraction of humic matter which was measured for light absorbance in a spectrophotometer at a wavelength of 550 nm. The extraction method has been criticized as the extraction technique itself may potentially alter the humic products that result and this may be further exacerbated by different plant

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ACCEPTED MANUSCRIPT macrofossil types (Caseldine et al., 2000). Species-dependent decomposition has been noted as a potential concern when employing this method most recently by Hughes et al. (2012). These issues

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were mitigated here by producing a macrofossil diagram to aid careful interpretation of results.

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Samples for testate amoebae analysis were prepared and counted in accordance with methods

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outlined by Charman et al. (2000). Two transfer functions were applied (Charman et al., 2006; Turner et al., 2013) to allow palaeo water-table depths to be estimated. The former is a Pan-European based function using primarily raised bogs whereas the latter is regionally specific to the area of this

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study (Yorkshire) with a training set from both raised and blanket bog. Upon comparison Turner et

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al., (2013) found that use of regional or supra regional transfer functions made little difference in the direction of the water table reconstruction but made some differences in the magnitude. The two

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transfer functions do, however, have some differences in the taxa present and their level of

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representation. Therefore, it was deemed prudent in the first instance to apply both functions to highlight any potential issues related to poorly represented taxa. Testate taxonomy employed here

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was directly related to the transfer functions and therefore water-table reconstructions should not suffer from taxonomic inconsistencies as highlighted by Payne et al. (2010). Counts of at least 100

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are generally considered sufficient to be representative samples (Payne and Mitchell, 2009) and were achieved in all but a few samples with low concentrations where counts of at least 50 were achieved. Recent research by Swindles et al. (2015) suggests that most available testate transfer functions are poor at reconstructing actual absolute values of mean depths to water tables but are reliable in terms of shifts in direction to wetter or drier conditions. Therefore, Swindles et al. (2015) recommend reporting standardised values to avoid confusion with contemporary water-table data that report reliable magnitudes. We therefore report both absolute and standardised water-table values to aid comparison with other studies.

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ACCEPTED MANUSCRIPT 4. Results 4.1 Peat depths and stratigraphy

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A history of catchment-wide peat development was obtained via peat depth and stratigraphic analyses (Blundell and Holden, 2014). The deepest peat is concentrated in three areas (Area 1-3)

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containing localized topographic basins within this water-shedding area (Figure 1) that represent the best locations for obtaining the longest palaeorecords. Sphagnum-rich peat as determined by in-field

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examination was also more prevalent in these deeper areas (Blundell and Holden, 2014) which are likely to have been foci of initial peat accumulation. Sources of water input to this area are from

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rainfall and indirectly from rainfall derived runoff from the upslope contributing area. Hydrological monitoring for 7 years (2008-2015) across all 3 areas of deep peat demonstrated the overriding

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importance of rainfall and evapotranspiration as controls of the modern water table (data not

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(e.g. Holden et al., 2011).

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shown). This process has also been shown to dominate in undrained blanket peatlands elsewhere

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4.2 Results from the detailed core analysis 4.21 Age-depth model, accumulation rates LOI Radiocarbon dates (Table 1) were combined with SCPs to derive a chronology for the core (Figure 2). SCP dates employed in line with Rose et al., (1995) were the ‘start’ c. AD 1850±25 at 11 cm, the ‘take off’ c. AD 1950±10 at 5 cm and the ‘peak’ at c. AD 1978±6 at 3 cm. Peat (>60% organic matter as shown by LOI) accumulation began at the core location at 176 cm (c. 880 BC MAR 1035 BC -643 BC) and at the deepest part of Area 1at 285 cm (c. 2020 -1850 BC 2σ range) from the present day surface. Low accumulation rates of 27-48 yrs cm-1 were evident from the base of the core until 146 cm depth. Accumulation rates increased thereafter with a mean of 11.9 yrs cm-1. Higher accumulation rates were coincident with evidence of Sphagnum moss. Organic matter was above 90% throughout the

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ACCEPTED MANUSCRIPT core except from from 194 – 180 cm depth (%OM <=20%) and from 179 - 169 cm depth with

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associated transitions from bedrock to regolith to peat.

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4.3 Macrofossil, testate amoebae and humification analyses

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The macrofossil record was zoned manually by eye (Figure 3) and these zones were applied to the testate amoebae data for ease of comparison. The main features of each zone are summarised in Table 2. From initiation of peat accumulation to c. AD 570 MAR AD 433-658, macrofossils were dominated

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initially by high levels of UOM (c. 730BC MAR 951 - 418 BC – 30 BC MAR 220 BC – AD 182) and subsequently a mix

415-632,

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of UOM, Eriophorum vaginatum and Ericaceae. Sphagnum established and peaked c. AD 560 MAR AD and fluctuated rapidly especially in the last 1000 years often replaced by Eriophorum

vaginatum/UOM which was often coincident with the presence of charcoal. This was most apparent

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in Zone E, Zone K, Zone M and Zone O. Changes in HYI from drier to wetter-indicating taxa are evident from c. 132 (c. AD 450 MAR AD 309-549), c. 124 (c. AD 570 MAR AD 433-658), 80 (c. AD 1010 MAR AD 89664 (c. AD 1170 MAR AD 1070-1273), 54 (c. AD 1260 MAR AD 1156-1352), 47 (c. AD 1330 MAR AD 1244-1387), 30 (c.

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1116),

AD 1620 MAR AD 1483-1686), 23 (c. AD 1720 MAR AD 1617-1820), 17 (c. AD 1820 MAR AD 1709-1899) and 13 cm (c. AD

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1880 MAR AD 1797-1939).

Absorbance values exhibit a long-term trend which is near linear from 0-125 cm (Figure 4).. The change in trend is coincident with the first recording of Sphagnum in the core. High humification absorbance values before this time were from an environment dominated by Eriophorum vaginatum and ericaceous plants probably reflecting unstable water tables (Hughes et al., 2000) that allowed more rapid and widespread decomposition through the peat mass. To permit a comparison of peat from different time periods this trend was removed by subtracting the absorbance values from an applied LOWESS smoothing function (smoothing parameter q = 0.5) and deriving the residuals (Figure 4a).

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ACCEPTED MANUSCRIPT Variation in humification following detrending, mainly reflects the proportion of UOM (highly degraded material) and/or Sphagnum remains (Figure 3). Also important are Ericaceae/UOM

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dominated zones that demonstrate higher levels of humification. Periods of high UOM and/or

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Ericaceae are likely to reflect drier conditions on the peatland surface whereas greater abundance of

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Sphagnum may generally reflect wetter conditions; although depending on the taxa, Sphagnum can inhabit hummock lawn and hollow environments potentially reflecting a range of hydrological conditions (Andrus et al., 1983). Sphagnum is also less susceptible to rapid decay due to the

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presence of phenolic compounds, lipids and waxes and extremely low nitrogen content (Clymo and Hayward 1982; Johnson and Damman, 1991), although different taxa exhibit different decay rates

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(Johnson and Damman, 1991). It is also possible that damage, especially by fire, could cause shifts in assemblages. Changes to less humified material occured from 168 (c. 510 BC MAR 790-253 BC), 144 (c. AD

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300 MAR AD 125-385), 132 (c. AD 460 MAR AD 308-549), 112 (c. AD 670 MAR AD 537-773), 102 (c. AD 770 MAR AD 662-849),

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80 (c. AD 1010 MAR AD 896-1116), 68 (c. AD 1130 MAR AD 1045-1232)), 54 (c. AD 1260 MAR AD 1156-1352), 47 (c. AD

MAR AD 1709-1899).

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1330 MAR AD 1244-1387), 31 (c. AD 1590 MAR AD 1470-1669), 23 (c. AD 1720 MAR AD 1617-1820) and 17 cm (c. AD 1820

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Testate amoebae concentrations were relatively low at levels deeper than 140 cm and therefore analysis was curtailed at that point (Figure 5). There was also a step-like reduction in diversity with an average taxa diversity of 12 types between 0- 60 cm and 6 types from 62 – 140 cm. This is most likely due to preservation issues. Some taxa are more resistant to decay than others (Swindles and Roe, 2007) which can lead to overrepresentation of certain taxa at greater depths. Here the taxa most resistant to decay tend to be those at the opposite ends of the hydrological gradient (and thus responsible for the large changes in direction of water table reconstruction) such as Archerella flavum, Amphitrema wrightianum and Hyalosphenia subflava. Therefore, some of the more subtle changes in the water table reconstruction may be absent due to test preservation at depth; however, directional changes (wetter/drier) should still be robust.

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ACCEPTED MANUSCRIPT Hyalosphenia subflava was the dominant taxon from 140 (c. AD 350 MAR AD 193-469) – 59 cm (c. AD 1210 MAR AD 1108-1317)

albeit punctuated by a twin peaked rise in Amphitrema stenostoma, Amphitrema

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wrightianum, and Archerella flavum, from 107 – 97 cm (c. AD 720 MAR AD 602-814 – 830 MAR AD 710-919).

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Thereafter, samples were comprised of mainly Hyaloshphenia subflava or Cyclopyxis arcelloides with

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more minor abundances of Trigonopyxis arcula, Difflugia pulex and Assulina muscorum. Breaks in this dominance occurred with a second twin peaked phase of Archerella flavum and Amphitrema stenostoma from 62 - 49 cm (c. AD 1190 MAR AD 1085-1287 – 1310 MAR AD 1213-1378) and with an increase in

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Nebela militaris and N. tincta in Zone G (Table 2) and an isolated peak (71%) in Cryptodifflugia oviformis from 12 – 8 cm (c. AD 1900 MAR AD 1825-1943 – 1940 MAR 1896-1955). Euglypha species were

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abundant at the surface, but rare further down the profile due to their poor resistance to decay as

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they are made of highly soluble siliceous plates (Tolonen, 1986a).

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Differences in the predicted absolute water-table levels were evident between the two testate transfer functions employed here. At sample points deeper than 60 cm especially there was a

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relatively consistent offset between the two functions of on average 10 cm, however the directions of change were generally in agreement (Figure 6). The offset was because the function determined

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by Turner et al. (2013) reconstructed depth to water table as much shallower due to the decline of Cyclopyxis arcelloides and Diflugia pulex. The function developed by Turner et al. (2013) assigned mean water table optima for these taxa of 23.6 and 31.0 cm respectively as opposed to 10.6 and 8.5 cm calculated by Charman et al. (2006). The optimum for Difflugia pulex is only calculated from a single occurrence in the training set in the Turner et al. (2013) derived function and therefore deemed to be not as suitable as that from the ACCROTELM-based function which had 26 occurrences in the depth to water table training set. Opposing directions of change in the two transfer function derived water-table records were rare but were evident at 28-29 cm and 13-15 cm. The former was due to the existence of high levels of Cyclopyxis arcelloides and Difflugia pulex and the latter was due to an increase in Cyclopyxis

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ACCEPTED MANUSCRIPT arcelloides alone. These taxa have already been identified as being modelled differently by the two transfer functions. The ACCROTELM function was employed from this point for discussion. This

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function offered more reliable reconstructions for Difflugia pulex which is an important taxon at the

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site. Changes in the reconstructed depth to water table from deep to shallower levels were evident

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from 132 (c. AD 460 MAR AD 308-549), 112 (c. AD 670 MAR AD 537-773), 102 (c. AD 770 MAR AD 662-849), 89 (c. AD 910 MAR AD 790-1023), 80 (c. AD 1010 MAR AD 896-1116), 61 (c. AD 1200 MAR AD 1090-1298), 54 (c. AD 1260 MAR AD 11561352),

47 (c. AD 1330 MAR AD 1244-1387), 43 (c. AD 1380 MAR AD 1301-1427) 30 (c. AD 1620 MAR AD 1483-1686) and 19

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cm (c. AD 1790 MAR AD 1686-1880).

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5. Discussion

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5.1 Proxy comparisons

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From c. 730 BC MAR 951- 418BC - AD 440 MAR AD 296-542 (the point at which testate amoebae analysis begins) there was little variation in HYI, despite changes in abundance between UOM and Eriophorum

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vaginatum in the macrofossil record (Figure 3-4). This was a consequence of the similar weighting given to these components with regard to their position on the water-table gradient in the

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hydroclimatic index (HYI). Over this period changes in humification occurred coincidently with fluctuations in UOM and E. vaginatum. Thereafter, evidence from all proxies for potentially shallower water tables occurred from c. AD 460 MAR AD 309-549, c. AD 1010 MAR AD 896-1116, c. AD 1250 MAR AD 1140-1347,

c. AD 1330 MAR AD 1244-1387 and c. AD 1620 MAR AD 1483-1686 (Figure 7). Any remaining ‘inferred’

changes in depth to water tables that were not supported by all proxies are discussed below. Changes to lower humification that were synchronous with lower macrofossil HYI alone were evident c. AD 1720 MAR AD 1617-1820 and AD 1820 MAR AD 1709-1899 (Figure 7). A shift to a shallower water table as reconstructed by testate amoebae marginally predated the former of these changes. However, Hyalosphenia subflava and Trigonopyxis arcula, both dry indicating taxa, were the dominant testate amoebae c. AD 1720 AD 1617-1820 (Zone L, Figure 5) which conflicted with lower HYI 15

ACCEPTED MANUSCRIPT values derived from a dominance of Sphagnum magellanicum (Figure 3) and lower values of humification. The conflict here may be a consequence of the potential of Sphagnum magellanicum

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to occupy a wide hydrological niche (Hammond et al., 1990) including drier conditions. Lower

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humification levels may also reflect more of a species-derived humification change as the

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assemblage shifted from Eriophorum vaginatum to S. magellanicum, the latter of which has a reportedly very low k value (Overbeck, 1947; Hughes et al., 2012).

Changes to lower levels of humification that were coincident with reconstructed shallower water

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tables as derived by testate amoebae data, but which were in conflict with the HYI were evident c.

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AD 670 MAR AD 537-773 and c. AD 770 MAR AD 662-849 (Figure 7). Here the macrofossil record is composed of taxa that have been given similar weightings to derive the HYI (UOM, Eriophorum vaginatum and

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Ericaceae). Remains of Sphagnum section Cuspidata, typical in hollow microforms, existed from AD

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610 MAR AD 471-711) – 770 MAR AD 662-849, albeit only 1-2%, providing a hint of wetter conditions, but this was not enough to affect the HYI. Vegetation typically present in hollow microforms may be

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underrepresented here as they have been found to be less resistant to decay (Johnson and Damman, 1991; Hájek, 2009).

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An increase in Arcella discoides in the testate amoebae record indicated a change to wetter conditions c. AD 910 MAR AD 790- 1023 that is not synchronous with a change in either of the other proxies. The hydrological implication was not clear as Arcella discoides occurred together with Hyalosphenia subflava which were from opposite ends of the hydrological gradient (Charman et al., 2006). This combination is not unusual in peatland archives (Blundell and Barber, 2005) and it has been proposed as reflecting large inter-annual variations in water-table depths with wet and dry taxa being active at different times of the year (Booth, 2008). Although a shift to wetter conditions at the site is supported by all proxies c. AD 1330 MAR AD 1244-1387, the testate amoebae record alone suggests that this shift is a short-lived event. Macrofossils showed a rapid change over time from Eriophorum vaginatum to Sphagnum magellanicum, which was 16

ACCEPTED MANUSCRIPT unrelated to the charcoal record, thus ruling out any ecological response to a cessation in burning. Testate amoebae reflected the shift to wetter conditions to some extent, with a minor increase in

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Arcerella flavum and Amphitrema stenostoma and lower levels of Hyalosphenia subflava: however

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there was also an increase in Nebela tincta and Arcella catinus, both of which were modelled as

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5.2 Palaeoenvironmental record at KMRC

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relatively dry indicators by both Charman et al. (2006) and Turner et al. (2013).

Major changes in vegetation and hydrology at this site were likely to be mainly the result of

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interactions between allogenic factors including climate change and anthropogenic disturbance such as burning, draining or peat cutting or atmospheric pollution. Autogenic factors may also be

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important and can facilitate changes in a palaeo-record that may be open to misinterpretation. For

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example, changes towards inferred ‘drier conditions’ from proxy indicators may be assumed to be due to allogenic factors when, as noted by Aaby (1976), these may be caused by autogenic factors

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under stable climate conditions. Swindles et al. (2012), using a virtual modelled bog and applying precipitation scenarios, were able to show that although peatland water tables do respond to

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climate, the peatland archive can be affected by complex internal responses that are non-linear. Evidence of climate induced change can potentially be supported via comparison with other regional palaeoenvironmental records, as can the possible influence of human activity by examination of the charcoal record and regional history. Evidence of macroscopic charcoal remains at KMRC indicates burning either directly on the site or very close by (Tolonen, 1986b); however, identifying whether charcoal is the result of deliberate human activity or natural wildfires initiated by lightning strikes using the charcoal record alone is problematic. Charred remains can, however, be produced by natural wildfires initiated by lightning strikes.

17

ACCEPTED MANUSCRIPT Peat accumulation at the deepest part of Area 1 initiated between c. 2020 – 1850 BC (2 sigma calibrated range) in the ‘Bronze Age’. This was a small localised basin within this ‘overall water

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shedding’ area conducive to water collection and hence early peat formation. The core location was

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50 m up a gentle slope (c. 5°) from here and peat initiation, likely caused via paludification, was c.

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880 BC MAR 1035 -643 BC and therefore was coeval with the Bronze/Iron Age boundary. For peat initiation to have occurred a shift in local hydrological conditions was required. Although peat initiation can occur as a consequence of succession through pedogenic processes (Taylor and Smith, 1980; Lawson

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et al., 2007), abundant charcoal was evident around the mineral/peat interface at the coring locaction, and elsewhere in Area 1-3 (Figure 1) where deep peat exists on the site, as shown by

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stratigraphy logs (Blundell and Holden 2014). This links initiation to probable anthropogenic activity at KMRC. Use of fire for tree clearance or improvement of grazing has long been suggested as a

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mechanism for blanket peat initiation in Britain and Ireland (Smith 1970; Moore, 1975, 1993;

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Charman, 1992; Huang, 2002). Burnt substrate can exhibit altered drainage properties (Mallik et al.,

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1984) becoming less permeable, increasing the potential for waterlogging. Charcoal at the time of peat initiation at KMRC and later in the Iron Age period is likely a result of burning to improve

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grazing on what was an environment of graminoids and some ericaceous taxa (Figure 3). There is substantial evidence for human activity in the region during the Bronze Age as numerous barrows, cairns and stone circles are evident in nearby areas such as Baildon and Rombalds Moor in the Aire and Calder valleys (Keighley, 1981). Pollen records in the region from sites 20 and 45 km south of KMRC at Rishworth Moor (Bartley, 1975) and Featherbed Moss (Tallis and Switsur, 1973) and 9 km to the southeast at Extwistle Moor (Bartley and Chambers, 1992) show elatively little vegetative/ecological impact of human activity in the Bronze Age. . However impact increased into the Iron Age with evidence of pastoral and arable agriculture with associated loss of woodland. Substantial Iron Age presence in the region is indicated by hill forts at Castercliffe (within 15 km) and further south at Almondbury (35 km) together with many enclosures and cairns especially around Green Crag Slack (Ilkley) and Hirst Wood (Shipley) (Keighley, 1981). 18

ACCEPTED MANUSCRIPT A wetter climate has also been strongly implicated in the formation of blanket peat (Solem, 1986; Tallis, 1991; Tipping, 2008). The radiocarbon date (c. 2020 – 1850 BC) derived for the mineral/peat

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interface in the deepest part of Area 1 (Figure 1) is coherent with transitions to wetter conditions as

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indicated in other peat-based records across Northern Europe: in central Scotland after c. 2050 BC

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(Charman et al., 2006); in Northern England (Hughes et al., 2000) from c. 2460-2040 BC (2σ error); Scandanavia c. 1970 BC (Vorren et al., 2012); and across the Atlantic in Newfoundland at c. 2050 BC (Hughes et al., 2006). Coherent shifts in climate are also recorded by increased river flooding activity

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in the UK between 2450-1650 BC (Macklin et al., 2010), high lake level high-stands in the French PreAlps c. 2250 BC and c. 2100-1900 BC (Magny et al., 2012) and increased drift ice (c.2250 – 2050 BC)

643 BC

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in the North Atlantic (Bond, 2001). Peat initiation at the core location in this study c. 880 BC MAR 1035 was also coherent with the onset of change to a wetter climate across northwest Europe at the

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Bronze/Iron Age transition (van Geel et al., 1996; Swindles et al., 2013; Charman et al., 2006), a

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period linked with major fluctuations in solar activity (van Geel et al., 1996, 1998) and ocean

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circulation patterns (Bond et al., 1997; 2001). Throughout the Romano-British period, peat accumulation remained low at c. 32 yrs cm-1 and the

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macrofossil record was dominated by Eriophorum vaginatum. This taxa is often associated with peatland environments that experience low pH and low base saturation (Wein, 1973) and has, in raised bogs at least, been suggested as indicating an unstable water table where insufficient peat had built up to successfully impede drainage (Hughes et al., 2000). Lack of Sphagnum to this point may reflect an inability to retain a sufficiently stable store of water due to a shallow substrate on what is gently sloping topography. Abundant Cenoccoum spores in zone C (Figure 3) lend support to this having been a more aerated substrate susceptible to drying out (Hughes et al., 2000). Consistent burning, as shown by high counts of charcoal throughout the Romano-British period, would also have favoured the presence of E. vaginatum and actively discouraged Sphagnum colonisation (Lindsay, 2010). E. vaginatum can withstand fire damage and often proliferates after burning of the peat surface due to release of nutrients (Ratcliffe, 1959; Wein, 1973). Evidence exists from pollen 19

ACCEPTED MANUSCRIPT records, from Featherbed Moss Moor (Tallis and Switsur, 1973) and at nearby Extwistle Moor (Bartley and Chambers, 1992), for increased human activity in the region, in both the Iron Age and

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through much of the Romano-British Period. The end of Romano-British period and initial part of the

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‘Dark Ages’ was marked by the establishment of Sphagnum c. AD 570 MAR AD 432-658. The colonisation

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by Sphagnum was coincident with a reduction in burning and proceeded evidence of a relatively minor change to a shallower in water table from c. AD 460 MAR AD 309-549 to c. AD 556 MAR AD 415-630 as reconstructed by testate amoebae. A reduction in burning evident at c. AD 610 MAR AD 470-711 reflects

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the diminished level of human impact, which may be partly due to increased wetness making burning less viable. Reduced human activity was evident in the wider region as woodlands

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expanded in post-Roman times (Tallis and Switsur, 1973). The minor elevation in water table, which was either a result of a more stable substrate, now potentially capable of holding water, or an

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increase in water input, together with reduced burning would be more favourable to Sphagnum

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colonisation. Source water for the coring location would have been either directly as rainfall or

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indirectly from upslope, but ultimately also from rainfall. Coeval with the colonisation of Sphagnum was a well-documented and widespread change to wetter/cooler climatic conditions across northwestern Europe often termed the ‘Dark Ages’ (Lamb 1977, 1995) c. cal. 1400 BP (c. AD 550) that may

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have provided the impetus for Sphagnum colonisation at the coring location. Other peatlands in Europe have registered changes in development around this time (Blackford and Chambers, 1991; Blundell and Barber 2005; Charman et al., 2006; Swindles et al., 2013) indicative of wetter/cooler conditions, that are coherent with periods of glacier advances c. AD 500-600 (Holzhauser et al., 2005) and narrower tree rings (Briffa et al., 1992) in Europe. Having established, Sphagnum remained, but did not become dominant until the first millennia AD whereupon there was evidence for a substantial increase in wetness as determined by all proxies c. AD 1060 MAR AD 1009-1165, peaking at c. AD 1100 MAR AD 1024-1200 and evidence of S. magellanicum . Macrofossils were instead a mix of increasing UOM, ericaceae and fluctuating monocotelydons, especially E. vaginatum, all of which translate into a relatively high and uniform HYI. However, 20

ACCEPTED MANUSCRIPT prominent increases in abundance of testate amoebae taxons Archella flavum, Amphitrema stenostoma and wrightianum from c. AD 670 MAR AD 537-773 and AD 770 MAR AD 662-849, together with

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lower levels of humification and reduced burning, provide strong evidence for short-lived periods of

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intervening wetter bog conditions. Temporally coherent changes to wetter conditions at Tore Hill

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Moss in Scotland (Blundell and Barber, 2005) c. AD 700 and AD 1090 and also in Ireland (Blundell et al., 2008) c. AD 805 and 1040 have been reported potentially implying a common allogenic forcing mechanism. The latter change is also shown in the extremely high temporal resolution record from

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Lille Vildmose in Denmark (Mauquoy et al., 2008) from c. AD 1020 and the compilation for northern Britain c. AD 1090 (Charman et al., 2006). Documentary records left by the Cistercian Monks who

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founded numerous Abbeys in the region describe how years in the mid-12th century were particularly wet leading to numerous abbey site relocations (Donkin, 1969). Given the position of the

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coring site, with water being received primarily by rainfall or indirectly from runoff or through flow

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down slope from the watershed, changes in climate were likely to be highly influential. However, it is

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clear that linking a number of changes that occur over such a small span of time with certainty between sites is highly problematic due to radiocarbon errors.

877-1094 and

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Variable levels of charcoal from c. AD 770 MAR AD 661-849 - 1280 MAR AD 1178-1361 with peaks c. AD 990 MAR AD AD 1160 MAR AD 1009-1165 point to human impact on the site throughout this period (Figure 6).

These were times of new influxes of people to Yorkshire such as Norse and later Norman invaders (Muir, 1997) that may have used burning to improve grazing at KMRC. Benefits of moorland burning were certainly well documented in Medieval times (Tinsley, 1975) for their role in improving pasture. The KMRC region from AD 1132 would also have been influenced by the establishment of Cistercian Abbeys in Yorkshire as large areas of land, including moorland for grazing purposes (Hey, 1986) were acquired, with many ‘granges’ (centres of outlying farming estates) being established in the area by AD 1200 (Donkin, 1969). KMRC and the surrounding marginal areas would have likely been under increasing pressure later in this period (AD 1086 to AD 1377; Hey, 1986) as population across Yorkshire rose seven-fold. 21

ACCEPTED MANUSCRIPT Fluctuating but generally wetter bog conditions were suggested by testate amoebae reconstructions and mirrored by reduced humification towards the end of the Medieval period (Figure 7) from the

Coincident with these changes was an increase in Sphagnum magellanicum after a

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MAR AD 1244-1387).

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13th to early 14th century AD (c. AD 1200 MAR AD 1094-1311 and c. AD 1250 MAR AD 1140-1347, and c. AD 1330

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period of E. vaginatum. Evidence of S. section Cuspidata in this phase further supports a change to wetter bog conditions. Coherent changes have been documented from peatland records at nearby Malham Tarn Moss (Turner et al, 2014) where a rapid shift from dry to wet was evident c. AD 1280-

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1350 and further afield in Ireland (Blackford and Chambers, 1995; Blundell et al., 2008) and Denmark (Mauquoy et al., 2008). Documentary sources used to determine Lamb’s (1977) winter severity index

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for England showed more severe winters from the late 13th century and early 14th century. Lamb’s summer dryness index, which is more related to the critical parameter of summer water deficit

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(Charman, 2007), displays a change to wetter summers from the early to mid-14th century. This is

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also supported by years of ‘bad summers’ (AD 1314, 1315) and ‘torrential rains’ (AD 1315-1316) that

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were recorded for the region (Hey 1986). Although relatively distant from the region, annually resolved reconstructions of spring-summer precipitation variability in East Anglia (Cooper et. al., 2013) and from southern England (Wilson et al., 2012) from tree ring records also show a clear

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increase in spring-summer precipitation in the late 13th and early 14th centuries. Such changes in climate were likely to have led to a general rise in water table height over this period which is evident in the KMRC record. Absence of charcoal remains in the record from c. AD 1300 MAR AD 1193-1375 to 1500 MAR AD 1382-1626 indicates a cessation of burning (Figure 7). Occurrence of disease affecting livestock (AD 1313-17 and 1319-21) and Scottish raids as far south as Pontefract (AD 1314 - 1319) may have driven changes in land management practices (Hey, 1986). By spring AD 1349 the Black Death arrived in Yorkshire and caused a major reduction in population. There would therefore have been reduced pressure on land for agriculture and livestock, thus reducing the likelihood of burning in marginal areas (Hey, 1986) including KMRC and elsewhere in the region (Tallis and Switsur, 1973; Turner et al., 2014). By AD 22

ACCEPTED MANUSCRIPT 1530 population had recovered and by the early 1500s there was re-encroachment of agriculture into more marginal areas of the region (Hey, 1986). This agricultural expansion was coherent with

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the reappearance of charcoal, increases in UOM, humification and loss of Sphagnum in the KMRC

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record.

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In the late 16th to early 17th century, Sphagnum section Acutifolia returned, as levels of humification and Hyalosphenia subflava abundance declined. This could be interpreted as a change to wetter conditions on the site. As in other instances in the archive, however, it is unclear as to whether the

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change from decomposed peat with charcoal remains to Sphagnum dominated, largely charcoal free

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peat is a symptom of reduced human activity alone, or a result of changing climate to wetter conditions that both discourages burning and allows Sphagnum to proliferate. Temporally coherent

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documentary records suggest that in Yorkshire there were ‘heavy rains’ and ‘poor harvests’ in 1555-

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1556, the 1580s and the 1590s (Hey, 1986), a trend largely reflected in the rest of England (Lamb, 1995). Reconstructed spring/summer precipitation from tree ring data from England by Cooper et al.

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(2013) also suggests enhanced precipitation in the late 16th century. Further afield, documentary evidence from Switzerland demonstrated a marked decline in mean annual temperature of 0.6°C

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from AD 1560 with 0.8 °C cooler summers and up to 20% wetter conditions, leading to a fourfold increase in flooding in the following decades (Pfister, 1992). Changes in the proxies at KMRC from the 18th century to the present day were not synchronous (Figure 7) as human activity takes on a more dominant role. Burning together with the likely influence of elevated air pollution (SOx and NHx compounds) led to a fundamental change in the vegetation and physical characteristics of the peat at KMRC especially over the last 100 years (Blundell and Holden, 2014). Wildfires are known to have occurred at the site in 1918 and in the 1940s and together with subsequent and continuing smaller patch scale burning for grouse moor management have resulted in substantial charcoal. These fires have, in part, led to an ‘atypical’ change in macrofossils and an ‘artificial’ surface vegetation dominated by Calluna vulgaris (Blundell

23

ACCEPTED MANUSCRIPT and Holden, 2014) and Campylopus pyriformis, a species that commonly colonises after fire events (Thomas et al., 1994). This change represents a large perturbation of the ecosystem; a judgment we

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are able to deliver because of comparison with the reconstructed environmental history of the site

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gained in this study.

6. Conclusions

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General

Use of peat depth and stratigraphic surveys in the blanket peat at KMRC, combined with high



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resolution analysis of a peat core have shown that:

Multi-proxy records from blanket bogs are achievable and can provide details of

Areas of blanket bog sites can have high levels of accumulation and provide conditions to

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

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palaeoenvironmental /palaeoclimate change.



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permit good preservation of both testate amoebae and macrofossils. These records can provide information to demonstrate the degree of response of the ecosystem to environmental perturbations of the past such as climate change and human

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influences including prescribed burning which can then be used to inform future management.

Specific A valuable record of palaeoenvironmental changes for the late Holocene, shaped by climate, human activity and some autogenic influences has been determined: 

Peat initiated in the deepest part of Area 1 (area of deep peat) c. 2020 – 1850 BC and at at the core site used for detailed palaeoeocological analyses c. 880 BC MAR 1030 BC -640 BC. These initiations are coherent with a wetter/colder climate, as determined from other regional

24

ACCEPTED MANUSCRIPT archives, and also a high incidence of charcoal suggesting a potential human/climate causal mechanism. Evidence suggesting prolonged periods of more elevated water tables have been

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

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reconstructed using all three proxies (macrofossil, humification and testate amoebae) c. AD

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460 MAR AD 309-549, , c. AD 1010 MAR AD 896-1116, c. AD 1250 MAR AD 1140-1347, c. AD 1330 MAR AD 1244-1387 and c. AD 1620 MAR AD 1483-1686 . Further well-supported changes to elevated water tables are evident c. AD 670 (MAR AD 537-773 and c. AD 770 MAR AD 662-849 . These changes are coherent with

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similarly timed changes in other peatland and non-peatland archives pointing towards a link with climate.

Burning has been an important environmental factor that has affected the site since its

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

initiation to the present day. Incidence of burning before the 20th century was generally in

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anti-phase with indicators of wetter conditions suggesting a link between the two. Burning

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may be less viable in wetter conditions or when the pressure to use marginal land is

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reduced. Cessation of burning was coincident with the ‘Black Death’, a period of declining population.

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Acknowledgements

We are grateful to Yorkshire Water who funded the research undertaken in this paper. We are also grateful to Yorkshire Water, Mr Robin Feather, Mr Kevin Benson and Mr David Airey for allowing access to the study site and providing useful local information. Thanks also to Dylan Young for providing very useful comment.

25

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ACCEPTED MANUSCRIPT Table Captions Table 1. AMS radiocarbon dates, calibrated (2 sigma range). Dates are from the core used for

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detailed palaeoecological analyses except for the final entry which dates the deepest peat/mineral

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interface in Area 1 (Figure 1). 14

Depth (m)

C Age

Material

KM_20_BLUND

0.205

Sphagnum leaves/branches/stems

UBA-18259

KM_28_BLUND

0.285

Sphagnum leaves/branches/stems

UBA-18260

KM_42_BLUND

0.425

Sphagnum leaves/branches/stems

UBA-18672

KM_73_BLUND

0.735

UBA-18671

KM_98_BLUND

UBA-18673

+/-

Cal 2δ range

Cal 2δ range

BP

AD/BC

177

30

-26.3

- 4 - 295

1954 -1655

258

32

-37.1

-3 - 432

1953 - 1518

580

27

-30.5

535 - 646

1415 - 1304

Sphagnum leaves/branches/stems

909

25

-32.7

744-914

1206 - 1036

0.985

Sphagnum leaves/branches/stems

1227

27

-24.3

1068-1259

882 - 691

KM_122_BLUND

1.225

Sphagnum leaves/branches/stems

1472

38

-30.6

1296-1480

654 - 470

UBA-18677

KM_140_BLUND

1.405

Bulk peat

1664

34

-29.2

1421-1693

529 - 257

UBA-18676

KM_154_BLUND

1.545

Bulk peat

2078

35

-25.6

1950-2142

1 - -192

UBA-18263

KM_174_BLUND

1.745

Bulk peat

2785

26

-29.3

2796 - 2954

-846 - -1004

UBA-20133

KM_285_BLUND

2.85

Bulk peat

5100

30

-30.4

3968 - 3800

-2018 - -1850

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UBA-18258

AMS 13 δ C

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Code

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Lab no.

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Table 2. Summary of proxy data from KMRC and implications. Zone (cm)

Age (AD/BC)

Macrofossil

A

- 850 BC

189 - 175

MAR 1025 BC-548 BC

Quartz grains and some finer mineral matter together with charcoal fragments and monocot remains.

Dominated by xeric Hyalosphenia subflava.

560 MAR 415- 631 –1010 MAR

Ericaceous and monocot remains dominate. Sphagnum evident for the first time. Sphagnum section Acutifolia predominately but some evidence of Sphagnum section Cuspidata at start of zone.

Overall dominated by Hyalosphenia subflava. Archerella flavum peaks at 48 and 42% c. AD 780 and 730 together with elevated Amphitrema stenostoma / wrightianium.

Dominated by Sphagnum magellanicum and Sphagnum section Acutifolia. Ericaceous roots evident ~20%.

1134-1337

1240 MAR 1134-1337 –1340 MAR 1254-1392

56 – 46.5 1340 MAR 1254-1392 –

46.5 41.5

1400 MAR 1315-1492

H

1400MAR 1315-1492 –1450 MAR

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G

1355-1558

41.5 – 38.5 I

1450

MAR 1355-1558 –1620 MAR

1483-1686

39.5 – 30.5

J

1620 MAR 1483-1696–1660 MAR 1533-1747

30.5 – 27.5 K

1660 (MAR 1533-1747) –1720 (MAR 1616-1820)

27.5 – 23.5 L

Overall highly humified peat. Variations reflect UOM levels. Lower humification coincident with greater Eriophorum vaginatum.

Eriophorum vaginatum dominated moor with frequent fires. Relatively dry.

Overall highly humified peat. Variation reflects UOM levels. Lower humification coincident with greater Sphagnum and Eriophorum vaginatum.

Mixed vegetation Sphagnum/ericaceous/Sedge. Evidence of Sphagnum section Cuspidata suggests increase in wetness initially. Frequent localised burning possibly limiting Sphagnum.

Overall dominated by Hyalosphenia subflava. Archerella flavum peaks at 9 and 41% c. AD 1120 and 1230 with elevated Amphitrema stenostoma.

Lowering humification as Sphagnum becomes prevalent. Variation reflects UOM and Sphagnum.

Sphagnum lawn. Burning phase is associated with decline in Sphagnum in the middle of this zone.

Sphagnum declines as Eriophorum vaginatum increases. Lack of charcoal.

Peak (45%) in Archerella flavum c. AD 1300.

Variation reflects UOM and Sphagnum.

Change from a Sphagnum lawn to Eriophorum vaginiatum. Relatively dry with brief wet phase.

Reduction in Eriophorum vaginatum as Sphagnum section Acutifolia and subsequently Sphagnum magellanicum increases to dominate.

Declining Hyalosphenia subflava to <20%. Increase in Nebela militaris and tincta and Arcella catinus.

Low humification reflecting abundant Sphagnum.

Transfer to a Sphagnum lawn from Eriophorum vaginatum. Increase in water table and no burning activity.

Major decline in Sphagnum magellanicum as Eriophorum vaginatum remains dominate. No Charcoal.

Increase in Hyalosphenia subflava to 50% and Trigonopyxis arcula.

Rise in humification as UOM increases.

Return to Eriophorum vaginatum. Greater DTWT. No burning.

Increase in UOM (>60%) as Eriophorum vaginatum remains decline. Sphagnum evident but low. Evidence of Cenococcum and charcoal.

Dominated by Hyalosphenia subflava (60%).

Sustained high humification as UOM increases.

Sustained greater DTWT. Increase in burning activity.

Increase in Sphagnum section Acutifolia to > 60%. No Charcoal.

Reduction of Hyalosphenia subflava as Difflugia pulex increases.

Low humification coincident with Sphagnum.

Lack of burning coincides with a return to Sphagnum

Increased Eriophorum vaginatum (>60%) remains. Increasing charcoal.

Elevated Hyalosphenia subflava to ~60% and reduced Nebela militaris.

Elevated humification as Sphagnum declines.

Greater level of burning associated with a decline in Sphagnum and increase in Eriophorum vaginatum and greater DTWT.

S. magellanicum dominates (>60%).

Sustained Hyalosphenia subflava, increasing Trigonopyxis

Low humification coincident with

Lack of burning coincides with a return to Sphagnum.

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80 - 56

1720 (MAR 1616-1820) –1810 (MAR 1700-1888)

Development of thin soil upon regolith. Area being burnt.

Shallow organic substrate with mix of monocot and ericaceous plants including Calluna vulgaris.

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1010 MAR 896-1116 –1240 MAR

Implication

Highly humified peat.

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124 - 80

F

T

Dominated by fluctuating Eriophorum vaginatum and UOM. Charcoal fragments abundant. Ericaceous remains evident especially Calluna vulgaris.

896-1116

E

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30 BC MAR 220BC-AD 182 – AD 560 MAR AD 415- 631

155 - 124

D

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Few identifiable macrofossils. Ericaceous plants evident with monocots. Charcoal fragments abundant initially.

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850 BC MAR 1025 BC-548 BC – 30 BC MAR 220BC-AD 182

175 - 155

C

Humification

D

B

Testate amoebae

23.5 –

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1810 MAR 1700-1888 – 1880 MAR 1797-1939

18.5 – 13.5

N

1880 MAR 1797-1939 –1940 MAR 1896-1959

arcula. Return of Arcella catinus.

abundant Sphagnum

UOM increases with E. vaginatum. Extensive charcoal.

Hyalosphenia subflava declines as Cyclopyxis arcelloides, Archella flavum, Amphitrema stenastoma and Nebela flabullelum increase.

Peak in humification as Sphagnum declines.

Sphagnum declines in association with burning activity. Eriophorum vaginatum becomes prevalent.

S. papillosum dominates and. S.s.Cuspidata is also evident.

Major decline in Cyclopyxis

Low humification as Sphagnum increases

Lack of burning activity coincident with reinvigorated Sphagnum. A lawn habitat of Sphagnum papillosum.

13.5 – 7.5

arcelloides. Cryptodifflugia oviformis peaks

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~60%. Amphitremas decline.

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M

No charcoal.

T

18.5

Hyalosphenia subflava replaces Cryptodifflugia oviformis as

O

1940 MAR 1896-195) –2009

Hyalosphenia subflava substantial but declines throughout as Arcellas and Euglyphas increase to surface.

High humification as UOM increases and Sphagnum declines.

Major decline in Sphagnum associated initially with massive burning event/s (up to 70% of macro abundance). Further lesser burning events post AD 1960s. No evidence of Sphagnum at all thereafter.

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CE P

TE

D

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7.5 – 0

Ericaceous material increases. Calluna leaves/wood/flowers increase. Campylopus piriformis evident.

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dominant taxa.

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ACCEPTED MANUSCRIPT Figure Captions Figure 1. Location of KMRC (black triangle) with survey points and interpolated peat depths within

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the catchment area. Deep peat is denoted in Areas 1-3. Grey shading in lower inset denotes land

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over 200 m in altitude.

Figure 2. ‘Bacon’ based Bayesian age-depth model for the core from KMRC. The three upper charts from left to right denote the stability of the Markov Chain Monte Carlo iterations (>1000 iterations),

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and the prior (green line) and posterior (grey shading) for accumulation rate and memory employed. For the lower chart: blue shading shows age distributions of calibrated AMS 14C dates; green shading

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denotes calendar dates incorporated into model from SCP data; grey shading denotes the posterior age-depth model bounded by grey dots showing the 95% probability intervals of the model.

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Figure 3. Macrofossil diagram for the KMRC master core. Peat components are derived from averaged quadrat counts under low-power magnification (×10). Leaf counts are a breakdown of the

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% identifiable Sphagnum and consist of proportions based on a random selection of leaves (100 per sample interval where possible) identified at high magnification (×400). Bar graphs are absolute counts. For charcoal, Charcoal 1 represents proportion of charcoal in each quadrat count and is used

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only when absolute counts are not feasible due to the large level of remains. Charcoal 2 represents the absolute count of charcoal pieces over 125 µm. The Hydroclimatic Index (HYI) is also displayed. Figure 4. Humification data displayed a) before and after detrending against depth (cm) and b) detrended data against age AD/BC. Figure 5. Testate amoebae diagram for KMRC. All data are percentages of the total number counted per depth level. Depth to water table reconstruction in centimetres from transfer functions derived by Charman et al. (2007) and Turner et al. (2013) together with associated errors derived from bootstrapping are displayed.

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ACCEPTED MANUSCRIPT Figure 6. Comparison between the two testate amoebae transfer functions employed; ACCROTELM (Charman et al., 2007, red line) and Turner et al., (2012) (black line) showing depth to water table

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(DTWT). Grey shading delimits areas of conflict between the two functions.

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Figure 7. Display of a) Charcoal record expressed as absolute number of fragments and percentage

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of macrofossil remains (when too numerous to count absolute fragments), and comparison of proxy records including b) z scores of the Hydroclimatic Index (HI) together with humification residuals, c) z scores of testate amoebae depth to water table and humification residuals and d) z scores of testate

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amoebae depth to water table data and HI. Grey shaded bands denote changes in depth to water

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table supported by all three proxies. Dashed lines denote changes in depth to water table supported

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D

by two proxies.

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49

ACCEPTED MANUSCRIPT Highlights 

Demonstrate how basins in blanket peatlands can provide valuable multi-proxy

Demonstrate that blanket bog sites can have high levels of accumulation and good

Demonstrate the response of the ecosystem to environmental perturbations which can then

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be used to inform future management.

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

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preservation of both testate amoebae and macrofossils.

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

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palaeorecords.

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