Palaeohydrology and the human impact on one of the largest raised bogs complex in the Western Carpathians (Central Europe) during the last two millennia

Abstract

The Central European area has been extensively studied using qualitative reconstruction techniques focusing on the development of peatlands in the past; however, research based on quantitative techniques is still lacking, especially in relation to highlands and mountainous areas. In this study, we focused on the hydrological changes and human-induced disturbances that affected two raised bogs from the Orawa-Nowy Targ Basin (Carpathian region): Puścizna Krauszowska and Puścizna Mała. We aimed to reconstruct the development of peatlands and changes in water table under different intensities of human activities. Two peat sequences from two different bogs, both possessing absolute chronologies based on high-resolution ¹⁴C dating, were examined in terms of pollen, non-pollen palynomorphs, plant macrofossils and testate amoeba records. We detected an asynchronous decrease in the water table level on the bogs that took place between the 4th and the 7th century ad, which occurred simultaneously with a global cold period ad 300–600 (Migration Period) in case of the Puścizna Mała bog. A concurrent but insignificant human impact on bogs was recorded. A distinct wet shift corresponding to the Wolf solar minimum (ca. ad 1280–1340) in Puścizna Mała was detected during ca. ad 1300–1350. The effect of this climatic event on bog hydrology is difficult to estimate because of the simultaneous human-induced deforestation. Drainage and substantial acceleration of peat extraction in the 19th and the 20th century ad led to the significant disturbances in peatland; however, these bogs were still susceptible to dry climatic events.

Keywords

late Holocene non-pollen palynomorphs peatland plant macrofossils southern Poland testate amoebae

Introduction

Ombrotrophic peatlands dominated by Sphagnum mosses occurring in the temperate and boreal zone of Northern Hemisphere are important carbon sinks (Yu et al., 2009) and unique habitats for relic plants of the Last Glaciation (e.g. Bastl et al., 2009; Koczur, 2006; Marcisz et al., 2015). Peat growth in the ombrotrophic bogs is dependent on precipitation, and the vegetation is isolated from mineral-rich groundwater. Furthermore, peatlands are very sensitive to climatic changes such as shifts in the water balance (the relationship between precipitation and evapotranspiration; Wieder et al., 2006) and thus perceived as highly suitable for palaeoclimatic reconstructions (e.g. Chambers et al., 2012; Gałka et al., 2016; Lamentowicz et al., 2008; Langdon et al., 2003; Nichols et al., 2009; Väliranta et al., 2012). Anoxic conditions and low pH provide suitable conditions for the preservation of pollen, plant macrofossils, testate amoebae (TA), non-pollen palynomorphs (NPPs) and other subfossils (e.g. Chambers et al., 2012; Moore et al., 1991; Rydin and Jeglum, 2006), making them invaluable archives of environmental changes.

The last two millennia were a period of substantial climatic and demographic changes in Europe. Apart from the recent climate-related warming (Hanhijärvi et al., 2013; Mann et al., 2003), many other significant climatic events occurred during this period, such as (1) 1.6 ka event (Bond et al., 1997, 2001) which occurred simultaneously with dramatic demographic changes referred to as the Migration Period (Büntgen et al., 2011); (2) the Mediaeval Climate Anomaly (MCA), also known as the ‘Mediaeval Warm Period’ (MWP; ad 800–1300); and (3) the ‘Little Ice Age’ (LIA; ad 1500–1850; Mann et al., 2009; PAGES 2k Consortium, 2013). The last centuries brought significant transformations, including total disappearance of many peatlands because of increasing human activities. Drainage and peat extraction may have led to transformation of vegetation, disturbances of stratigraphy as well as modification of climatic signal (Davies et al., 2015; Fiałkiewicz-Kozieł et al., 2015).

In this study, we focused on the Orawa-Nowy Targ Basin where the biggest raised bog complex (8255.6 ha) in Poland is located. Like many other peatland areas in Europe, the study area was strongly transformed by human activities (Łajczak, 2006). Previous palaeoecological studies conducted in the Orawa-Nowy Targ Basin based on analyses of pollen, plant macrofossils, a very limited set of identified NPPs, dendrochronology and TA traits (e.g. Kołaczek et al., 2010; Krąpiec et al., 2016; Marcisz et al., 2016; Obidowicz, 1990, 1996). These works focused on general patterns in the development of peatlands and vegetation history. However, there are no detailed in-depth palaeoecological research that are supported by quantitative reconstructions of bog’s hydrology. Herein, we present a multi-proxy study on changes in the peatland ecosystem based on pollen, a broad set of NPPs, plant macrofossils and TA-based quantitative reconstruction of water table depth during the last 2000 years. We aimed to reconstruct the development of peatlands and changes in water table, paying close attention to climatic and human impact changes.

Study area

The study area is located in the Orawa-Nowy Targ Basin (covering approximately 262 km² mainly at an altitude of 490–680 m a.s.l.), an area bounded by the Western Beskid Mountains (Babia Góra and Gorce ranges) in the north and the Tatra Mountains in the south (Figure 1). The Orawa-Nowy Targ Basin is a tectonic depression filled with Neogene and Quaternary deposits (Watycha, 1976). The limited permeability of the loam layer in this basin’s bed is a key factor that supports peatland development in this area (Łajczak, 2009; Kowanetz, 1998). Another factor which supports high-ground wetness is climate. Moderately cool climate in the basin with a tendency to stagnate cold air during the winter supports maintenance of snow cover for long periods (Kondracki, 1998; Lorenc, 2005). In addition, between May and October precipitation exceeds evaporation (Kowanetz, 1998; Obrębska-Starklowa, 1977). The heavy cloudiness and frequent fog further contribute to the condensation of water in the basin (Staszkiewicz and Szeląg, 2003). The basin’s mean annual temperature is 5–6°C; the coldest month being January (mean values range between −3.5°C and −4.0°C; Lorenc, 2005) and the warmest being July (mean temperatures reaching 15.6°C; Kowanetz, 1998). The basin’s annual precipitation is 900–1100 mm, which is highest in July (Lorenc, 2005).

Figure 1.

Location of Puścizna Mała and Puścizna Krauszowska sites: (a) across Central, Western and Northern Europe, dots and open circles with numbers reflect location of sites referred in the ‘Discussion’ section; (b) detailed relief map of the Orawa-Nowy Targ Basin and adjacent geographical units, black rectangles represent area shown in c and d; (c) aerial view on the PM bog (GoogleEarth, date of image acquisition 19 March 2015); and (d) aerial view on the Puścizna Krauszowska bog (GoogleEarth, date of image acquisition 19 March 2015).

As many as 420 species of vascular plants have been found in the Orawa-Nowy Targ peatlands, but only 57 of them were found growing on typical raised bog domes. Bog coniferous forests occupy vast areas adjoining the peat bogs. The area is/was a refugium of glacial relics such as Pinus mugo, Rubus chamaemorus (Koczur, 2006), and until the early 19th century ad, Betula nana (Lubicz-Niezabitowski, 1922).

Two peatlands – Puścizna Krauszowska and Puścizna Mała – were selected for this study, given their well-documented history of human-induced disturbances (Łajczak, 2006). The peat from both bogs is still being extracted; hence, the bog surfaces are continuously shrinking. According to Łajczak (2006), the contemporary Puścizna Krauszowska bog covered 79 ha, including 29 ha of the fragmentary dome, but the present surface of the dome does not exceed 5 ha (B. Fiałkiewicz-Kozieł, personal communication, 2008). The Puścizna Mała bog extends to cover an area of more than 125 ha with a dome surface area covering more than 51 ha. Historical sources revealed that the intensity of human activities varied over time. During the early Slavonic and the early Mediaeval periods, the boggy, forested and almost uninhabited area of the Orawa-Nowy Targ Basin was a natural barrier against the war raids from the south, which means human-induced disturbances were rare. From the late Mediaeval period, the increasing number of settlements brought about gradual deforestation, and the local people were encouraged to exploit the bog in different ways for subsistence, such as pastoral purposes and/or peat extraction. The peat extraction was not significant until the 20th century ad on the Puścizna Mała bog, whereas the increase in this activity started no earlier than 1930s in the Puścizna Krauszowska bog (Łajczak, 2006).

Methods

Coring and absolute chronology of the profiles

For the purpose of our study, the top sections of the peat deposits were collected. The Puścizna Mała profile was retrieved as peat monolith (135 × 20 × 20 cm) from an outcrop in the bog’s dome (613 m a.s.l., 49°28′06″N, 19°56′18″E) in June 2006 (Fiałkiewicz-Kozieł et al., 2014; Kołaczek et al., 2010). The Puścizna Krauszowska profile was collected from the centre of the dome (655 m a.s.l., 49°27′36″N, 19°47′12″E) in June 2008, using a Wardenaar sampler of dimensions measuring 100 × 10 × 10 cm³ (Fiałkiewicz-Kozieł et al., 2015; Kołaczek et al., 2010).

An absolute chronology is based on (1) the age–depth models based on numerous ¹⁴C dates (11 dates for Puścizna Krauszowska and 21 dates for Puścizna Mała) and constructed using the OxCal v. 4.2 software applying the P_Sequence function (Bronk Ramsey, 1995, 2008) and the IntCal13 atmospheric curve (Reimer et al., 2013) as the calibration set and (2) ²¹⁰Pb dates obtained for the topmost sections of the profiles (Fiałkiewicz-Kozieł et al., 2014, 2015; Figure 2). In the case of Puścizna Mała model, in comparison with the one published by Fiałkiewicz-Kozieł et al. (2014), two boundaries (introduced by the command Boundary) that reflect potential changes in the rate of peat accumulation were introduced at depths of (1) 114 cm – an abrupt decrease in pollen concentration and a fall in the content of amorphous organic matter and (2) at 103 cm – an increase in Sphagnum magellanicum (see the following sections) and an increase in bulk density (Fiałkiewicz-Kozieł et al., 2014). In the case of Puścizna Krauszowska profile, the age–depth model no. 3 has been selected from scenarios proposed in the paper by Fiałkiewicz-Kozieł et al. (2015; Figure 2). To facilitate a more detailed description and discussions about results, the age is presented as a µ (mean) value of the modelled age expressed by ad/bc, rounded to tens for the period before 20th century ad and not rounded values for the 20th and 21st centuries.

Figure 2.

Age–depth models from the Puścizna Krauszowska and Puścizna Mała profiles.

The ¹⁴C dating of both profiles revealed inversions in the layers between depths of 48.5 and 21 cm in Puścizna Krauszowska and 45 and 21.5 cm in Puścizna Mała, which hampered the calculation of absolute chronology (Fiałkiewicz-Kozieł et al., 2014, 2015). These fragments of the profiles were excluded from this study.

Testate amoebae (TA)

An analysis of TA was carried out to obtain quantitative estimates of the depth to water table (DWT) changes (Charman et al., 2007). Subfossil TA were extracted from 3–5 cm³ subsamples following the procedure described by Booth et al. (2010). The material was washed through a sieve of 250-µm mesh size, and the filtrate was used for microscopic analyses. Samples were counted under an upright microscope at 200× and 400× magnifications until a minimum of 150 tests was detected (Booth et al., 2010; Payne and Mitchell, 2008). Identification criteria were drawn from available literature, since we tried to achieve the highest possible taxonomical resolution (e.g. Clarke, 2003; Mazei and Tsyganov, 2006; Meisterfeld, 2001; Ogden and Hedley, 1980). DWT was estimated from TA using a training set consisting of 123 samples developed for northern Poland by Lamentowicz and Mitchell (2005) and Lamentowicz et al. (2008), which is the only training set available from Poland.

Pollen and non-pollen palynomorphs (NPPs)

Palynological analysis was used for the reconstruction of (1) terrestrial vegetation changes, (2) human impact and (3) qualitative water table fluctuations (e.g. Cugny et al., 2010; Gaillard, 2013; Moore et al., 1991; Poska et al., 2004). Preliminary results considering vegetation changes based on palynological analysis carried out on 60 samples, with very limited data considering NPPs, were published in the paper by Kołaczek et al. (2010). Consequently, in this paper, the focus is on the palaeohydrology and bog ecosystem dynamics. In this study, the resolution of pollen analysis chosen for the Puścizna Mała profile increased twice compared with the one used by Kołaczek et al. (2010), whereas with Puścizna Krauszowska profile, the number of samples from the bottom section increased. Samples (1 cm³ in volume) were prepared using standard laboratory procedures: (1) a 10% HCl solution was used to dissolve potential carbonates in the samples, (2) samples were heated in a 10% KOH to remove humic compounds and (3) samples were subjected to a minimum 24-h treatment with HF to remove mineral fractions. Next, acetolysis was carried out (Berglund and Ralska-Jasiewiczowa, 1986). One Lycopodium tablet of known number of spores (N = 10,679; produced by the Lund University) was added to each sample for calculating microfossil concentrations (Stockmarr, 1971). Using an upright microscope with 400× and 1000× magnifications, pollen and spores were counted until the number of arboreal pollen (AP) grains in a sample reached at least 500. In extreme cases where low concentrations of pollen material were present, pollen grains were counted to get a minimum of 250 AP grains. Pollen grains and spores were identified with atlases and keys (Beug, 2004; Moore et al., 1991) and the reference pollen slide collection of the W. Szafer Institute of Botany, Polish Academy of Sciences (Kraków, Poland). NPPs were identified using photographs and descriptions reported in various publications (e.g. van Geel, 1978; van Geel and Aptroot, 2006, as well as those cited in Miola, 2012). The NPP-type nomenclature follows Miola (2012). Percentages of pollen grains, spores and NPPs were calculated according to the following formula: number of taxon’s sporomorphs/TPS × 100%; here TPS (total pollen sum) includes both AP and NAP (non-AP, excluding aquatic and wetland plants such as Ericaceae and Cyperaceae, spores and NPPs).

Plant macrofossils

In the Puścizna Krauszowska profile, plant macrofossils were analysed from 1.5-cm-thick (depth: 0–15 cm) and 3-cm-thick (depth: 15–100 cm) slices of the profile, whereas in the Puścizna Mała profile, 2-cm-thick (depth: 0–28 cm) and 1-cm-thick (depth: 28–135 cm) slices were analysed. In both cases, slices (ca. 3–5 cm³ in volume) were deemed contiguous if the material was not utilized by other analyses. Each sample was washed and wet-sieved through 0.2-mm mesh screens. The carpological and vegetative remains (leaves, rootlets and epidermis) were identified using available keys and atlases (e.g. Grosse-Brauckmann, 1974; Mauquoy and van Geel, 2007). The volume percentages of the various unidentified vegetative remains and Sphagnum taxa were estimated to the nearest 5% with a stereomicroscope. The relative proportions of the taxonomic sections of Sphagnum were estimated on the basis of the branch leaves, using an upright microscope with two 22 × 22-mm cover glasses. Then, a species-level identification of the Sphagnum was separately performed using appropriate guides for identification (Hölzer, 2010; Laine et al., 2011). The moss nomenclature follows Ochyra et al. (2003), whereas the vascular plant nomenclature follows Mirek et al. (2002). The volume proportion of the amorphous organic matter, which serves as a measure of peat decomposition, was estimated during sieving in steps of 25% and was calculated on the basis of the ratio of the volume of plant remains on the screen to the volume of the sample prior to sieving (same procedure used in Gałka et al., 2013). In the case of Puścizna Mała profile, identification of fossil S. capillifolium and S. rubellum as well as S. angustifolium and S. fallax was found to be impossible due to the similar morphology of branches and stem leaves. Nonetheless, interpretation of DWT and acidity was not a serious problem because these species occur in similar habitats (Hölzer, 2010; Laine et al., 2011).

Presentation of results

The results of each analysis were summarized in diagrams drawn using the TILIA Graph programme (Grimm, 1991). The reconstructions of DWT were plotted in the C2 software (Juggins, 2003). Due to different sampling resolution in particular analyses, diagrams were divided into two common phases of bogs’ development on the basis of water table reconstructions and the level of human impact.

Results and interpretation: palaeoecological reconstruction

Phase I: Moderately wet conditions and low human impact (Puścizna Krauszowska: 100–48.5 cm, ca. 70 bc–ad 680; Puścizna Mała: 135–45 cm, ca. ad 120–1360)

The TA-inferred water table slightly fluctuated in both profiles but was the highest in the period spanned by both profiles. The mean DWT in the Puścizna Krauszowska profile was 10.7 cm, and in Puścizna Mała, it was 6.9 cm. About ad 1310–1350, the water table distinctly rose in the Puścizna Mała profile (up to DWT = 2 cm, Figure 3). In both profiles, S. magellanicum (in all samples, Puścizna Krauszowska: 5–90%; Puścizna Mała: 5–100%), S. angustifolium or S. angustifolium/fallax and Eriophorum vaginatum were the most frequent taxa among plant macrofossils. The oligotrophic character of the Sphagnum bog was highlighted by peatland-related microfungal NPPs, such as HdV-13, Tilletia sphagni (HdV-27), Lasiosphaeria cf. caudata (HdV-63A) and Geoglossum sphagnophilum (HdV-77A; van Geel, 1978). Some fungi, such as Anthostomella cf.fuegiana (HdV-4) and HdV-18, were probably related to E. vaginatum (van Geel, 1978; van Geel and Aptroot, 2006). In both sites, Archerella flavum dominated (Puścizna Krauszowska: 20–76%; Puścizna Mała: 0–81%), and Hyalosphenia papilio, Assulina muscorum and Heleopera petricola were common during this phase. In addition, in the Puścizna Mała profile, Amphitrema wrightianum, A. seminulum, Heleopera sphagni and Nebela militaris occurred in high frequencies. Among NPPs that originated from animals, Habrotrocha angusticollis (HdV-37) and spermatophores of Copepoda (HdV-28) were present. The former is connected with wet sites (Warner and Chengalath, 1988) and the latter with the presence of shallow pools in the mire (van Geel, 1978).

Figure 3.

Testate amoebae (TA) and TA-inferred depth to water table (DWT) from the Puścizna Krauszowska and Puścizna Mała profiles. The grey area of each column shows percentage values magnified by 10.

In both profiles, layers with very low TA concentrations were recorded (Puścizna Krauszowska: ca. ad 590–640; Puścizna Mała: ca. ad 370–460). This may have been a result of higher decomposition of tests under very dry conditions and/or increased acidity (cf. Mitchell et al., 2008; Swindles and Roe, 2007). Simultaneously, the highest content of E. vaginatum tissues in peat (Puścizna Krauszowska: 30–35% during the 4th to the 7th century ad; Puścizna Mała: 50–80% during the 3rd to the 5th century ad) and an increase in the content of amorphous organic matter may confirm decrease in the water table (Figure 4). In the Puścizna Mała profile, fungi Microthyrium sp. (HdV-8B) and HdV-201 reached maxima in the Puścizna Mała profile at the end or just above the layer lacking TA (Figure 5). The presence of the former taxon might be linked to pine needles, whereas the latter’s presence suggests the occurrence of dry microhabitats (van Geel et al., 1989).

Figure 4.

Plant macrofossils from the Puścizna Krauszowska and Puścizna Mała profiles. The grey area of each column shows percentages magnified by 10.

Figure 5.

Non-pollen palynomorphs (NPPs) and local pollen taxa from the Puścizna Krauszowska and Puścizna Mała profiles. The grey area of each column shows percentages magnified by 10. sapr.: saprotrophic.

Pollen analysis revealed the domination of mixed forests in the region (AP: 86–99%). The forests consisted of beech (Fagus sylvatica: 10–20% in Puścizna Krauszowska, 10–24% in Puścizna Mała), fir (Abies alba: 7–22% in Puścizna Krauszowska, 7–26% in Puścizna Mała) and spruce (Picea abies: 6–26% in Puścizna Krauszowska, 5–23% in Puścizna Mała), with an addition of hornbeam (Carpinus betulus: 3–9% in Puścizna Krauszowska, 1–10% in Puścizna Mała) and oak (Quercus: 3–10% in Puścizna Krauszowska, 3–10% in Puścizna Mała). The relative proximity of the edge of mixed forests to the coring spot is highlighted by the presence of spores of parasitic fungus Kretzschmaria deusta, which is characterized by the poor dispersal ability (cf. van Geel and Andersen, 1988). The drier parts of peatlands were occupied by pines (P. sylvestris type: 7–27% in Puścizna Krauszowska, 11–45% in Puścizna Mała) and birches (Betula: 6–14% in Puścizna Krauszowska, 7–20% in Puścizna Mała), whereas lags and riverine woodlands were occupied by alder (Alnus: 8–16% in Puścizna Krauszowska, 3–18% in Puścizna Mała). Alnus visibly retreated in the 5th (Puścizna Mała) and 7th (Puścizna Krauszowska) centuries ad. This episode was followed by the spread of pine in the coring area (maximum of P. sylvestris type in Phase I in the Puścizna Krauszowska and Puścizna Mała profiles, at ca. ad 630–650 and ca. ad 440–480, respectively), which started with a decline in TA frequency. Pollen of cultivated plants, such as Cerealia type, Secale cereale, Triticum type and Avena type, occurred in most of the spectra in both profiles, which indicates low human pressure. The presence of open communities, probably on alluvial plains, was most distinctly revealed by pollen of Poaceae undiff., Artemisia, Rumex acetosa type and Plantago lanceolata. A slight increase in human activity was recorded ca. ad 750, which was visible in more frequent presence of Artemisia, R. acetosa type, Chenopodiaceae and Secale cereale pollen.

Phase II: Dry conditions and strong human impact (Puścizna Krauszowska: 21–0 cm, ad 1900–2008; Puścizna Mała: 21.5–0 cm, ad 1840–2006)

The mean DWT was 26.3 cm for the Puścizna Krauszowska profile and 32.1 cm for the Puścizna Mała profile. In the Puścizna Krauszowska profile, DWT increased ca. ad 1967 (maximum in the profile) and decreased afterwards. In both profiles, TA communities were dominated by dry indicator taxa. In the Puścizna Krauszowska profile, Euglypha rotunda type and afterward Trinema lineare declined dramatically and were replaced by Phryganella acropodia, N. militaris, N. tincta s.l. and A. muscorum. H. elegans and H. papilio reappeared in the topmost layer. In the Puścizna Mała profile, the following taxa revealed subsequent maxima: first, P. acropodia and Heleopera sylvatica; then, T. lineare, Euglypha rotunda, N. tincta s.l. and N. militaris; and later, Trigonopyxis arcula. H. elegans, Euglypha strigosa and A. muscorum reached maximum values in the topmost spectra (Figure 3).

The Puścizna Krauszowska profile revealed very dynamic changes in Sphagnum communities as subsequent dominations of S. cuspidatum, S. rubellum, S. balticum, S. capillifolium and finally again S. rubellum. This suggests a sequence of an initial transition from a wet bog and/or the presence of a hollow towards dry bog conditions and/or the formation of a hummock. Afterwards, together with the occurrence of S. balticum, the microhabitat characterized by high water table reappeared, finally followed by dry conditions on the mire and/or hummock development (cf. Hölzer, 2010). The formation of a hummock and/or decrease in the water table on the bog provided a suitable habitat for C. vulgaris, whose pollen percentage maximum (40%) coincided with the domination of S. rubellum. These possible dry and wet shifts are poorly manifested by the TA composition, which revealed dry conditions during the entire phase; however, S. rubellum increases in frequency are parallel with decreases in the water table. In the Puścizna Mała profile, S. magellanicum and S. capillifolium/S. rubellum dominated, but mosses such as Polytrichum strictum and Aulacomnium palustre became more frequent. This set of taxa points to a continuation of relatively dry conditions (Bragazza and Gerdol, 1996; Manukjanová et al., 2014). Percentages of C. vulgaris reached the highest values in the Puścizna Mała profile and rapidly decreased afterwards (ca. ad 1924), but this retreat took place earlier in comparison with the Puścizna Krauszowska profile (ca. ad 1978). In both profiles, HdV-96A reached maxima of frequency (Puścizna Krauszowska: 16%, Puścizna Mała: 37%) that coincided with or occurred just after C. vulgaris’ optima (Figure 4).

Considerable landscape openness in the bog’s surroundings is reflected by low AP values (Puścizna Krauszowska: 50–87%, Puścizna Mała: 61–81%). However, in the Puścizna Krauszowska profile, AP revealed an increasing trend caused mainly by a rise in P. sylvestris type percentages (from 18% to 37%), which might have been an effect of pine spread on the mire surface and/or preference for this taxon in silviculture. In the vicinity of the bogs, cultivated fields (pollen: Cerealia type, Triticum type and Avena type), meadows and ruderal communities (pollen: Poaceae undiff., Plantago lanceolata, Artemisia, Chenopodiaceae and others) occupied considerable areas (Figure 6). The probable expansion of habitats rich in nitrogen was recorded by maxima of Urtica (cf. Ellenberg and Leuschner, 2010).

Figure 6.

Pollen of forest and open land taxa included to total pollen sum from the Puścizna Krauszowska and Puścizna Mała profiles. The grey area of each column shows percentages magnified by 10. The values of HdV-44 Kretzschmaria deusta are magnified by 10. L.c.TA: low concentrate of testate amoebae.

Discussion

Migration and Mediaeval Periods in the Orawa-Nowy Targ peatlands across climate and palaeohydrological patterns in Central European peatlands

The Migration and further Mediaeval Periods were characterized by high climate variability in Europe (Büntgen et al., 2011). One of the most climate-affecting events during this period was a discharge of the drifting ice to the Atlantic Ocean ca. ad 550 (Bond et al., 2001). This event appeared within the time frames of a larger global-scale period of climate changes (ad 300–600), which in Europe were recorded mainly as cold and wet phases (Wanner et al., 2011). These climate changes contributed to great demographic changes in Europe during the so-called Migration Period (Büntgen et al., 2011). At that time or just after, both examined bogs recorded intriguing spread of P. sylvestris on domes preceded by a distinct decline in the abundance of TA. Giving absolute chronologies in the Puścizna Krauszowska and Puścizna Mała profiles, it can be concluded that the aforementioned expansions of pine were diachronous (Puścizna Krauszowska: ca. ad 630–650; Puścizna Mała: ca. ad 440–480). This lack of synchronicity might be interpreted as an influence of the independent autogenic factors on both bogs or uneven susceptibility of these bogs to the same climatic/hydrological changes. Reconstruction by Büntgen et al. (2011) shows higher summer temperatures and lower spring precipitation in the 3rd century ad, what was a possible cause of dry conditions on peatlands. While in the 4th and the 5th century ad, reconstruction points out rather colder and wetter conditions during the vegetation season (Figure 7). This climate pattern seems to better explain the timing of vegetation changes recorded by the Puścizna Mała bog. Spread of P. sylvestris might have been a consequence of a decrease in the water table, whereas further retreat of pine was a response to the wet shift driven by cooler and wetter climate conditions (Figure 3). Łajczak (2009) suggested that the wetland complex including the Puścizna Krauszowska bog was much bigger than the one including the Puścizna Mała bog before the 15th century ad. Hence, Puścizna Mała, being a smaller bog, was more susceptible to climatic/hydrological changes compared to vast peatland complexes as Puścizna Krauszowska was (cf. Gałka et al., 2017a). This interpretation might be confirmed by a recent dendrochronological study from the Puścizna Wielka bog, adjacent to Puścizna Mała and much bigger than Puścizna Mała, which did not reveal any pine expansion on the bog during the first millennium ad (Krąpiec et al., 2016).

Figure 7.

Testate amoebae (TA)–inferred depth to water table (DWT) from the Puścizna Krauszowska and Puścizna Mała profiles on the background climatic and hydro-climatic reconstruction from Central and Western Europe during the period ad 1–1400.

The other palaeohydrological reconstructions from the period ad 300–600 for the Central Europe region revealed variable patterns. The Linje mire in north Poland recorded dry conditions and a rapid decline in peat accumulation during the period of ca. ad 100–400 (Marcisz et al., 2015). Other reconstructions from the northern area of Poland revealed various hydrological changes, for example, from wet to dry conditions in the Stążki bog from the 4th to 6th centuries cal. ad (northern Poland; Gałka et al., 2013), stable DWT in the Gązwa bog (GZII profile, north-eastern Poland; Gałka et al., 2015), a gradual decrease in the water table from ca. ad 400 to 600 in the Mechacz Wielki bog (Gałka et al., 2017b) and a gradual decrease in the water table from ca. ad 300 to 500 and then a sudden rise in the water table ca. ad 600 in the Bagno Kusowo bog (north-western Poland; Lamentowicz et al., 2015; Figure 7). To summarize, the differences in palaeohydrological records of the global climate event ad 300–600 (sensu Wanner et al., 2011) in Central Europe might have been highly dependent on local conditions, for example, bog size, local geology, topography and the influence of continental/oceanic air masses and/or internal dynamics of bog’s vegetation development.

Another period of distinct climate changes, recorded in several palaeoecological archives, was the MWP (ad 800–1300; Mann et al., 2003). In our records, this time interval was registered only by the Puścizna Mała profile. In the Northern Hemisphere, a peak of warming was estimated at ca. ad 950–1050 and characterized by ca. 0.6°C higher temperatures in comparison with the reference period ad 1880–1960 (Christiansen and Ljungqvist, 2012). The reconstruction by Büntgen et al. (2011) revealed the highest temperatures between ca. ad 1050 and ca. ad 1150 in Western Europe and a decrease in spring precipitation from the 10th century ad. These were preceded by a period of higher precipitation ca. ad 900 (Figure 7). The time frame of the warming peak during MWP (sensu Christiansen and Ljungqvist, 2012) overlaps with the Oort solar minimum (ca. ad 1010–1050, Wigley, 1988, or ca. ad 1060 following Magny et al., 2010). This minimum is considered as one of the drivers of a cold climatic spell, which was recorded by a rise in the water table at ca. ad 1050 (Mauquoy et al., 2008) and ca. ad 1090 (Charman et al., 2006). In the Puścizna Mała profile, MWP was reflected by moderately wet conditions with some minor increases in DWT ca. ad 950–1050 (warm optimum sensu Christiansen and Ljungqvist, 2012) and ca. ad 1230–1270. High water table during MWP was also characteristic of the Bagna nad Stążką fen (Lamentowicz et al., 2013) and following northern Polish bogs: Linje (Marcisz et al., 2015), Stążki (Gałka et al., 2013) and Słowińskie Błota (Lamentowicz et al., 2009; Figure 7). A similar pattern was reflected in peatlands from northern Romanian Carpathians (Diaconu et al., 2017; Feurdean et al., 2015). Nonetheless, even on a regional scale, the variability of hydrological response to MWP was detected in some parts of Europe, for example, the compilation of data from Ireland failed to reveal a clear signal for this period (Swindles et al., 2013). Central and Eastern Europe were not an exception in terms of this variability. This is visible, for example, in the Bagno Kusowo bog (northern Poland), which did not reveal any change towards wet conditions (only some relatively short-lived rises in the water table that appeared ca. ad 850 and 1200; Lamentowicz et al., 2015) in contrast to the above-mentioned sites from Poland. Similarly, in the Gązwa bog (north-eastern Poland), only a 200-year-long wet trend was identified at the beginning of MWP, followed by a period of a relatively stable water table (Gałka et al., 2015). The Mechacz Wielki bog (north-eastern Poland) revealed relatively stable water table (Gałka et al., 2017b). As in the case of first millennium ad, the combination of local physical conditions and autogenous development of vegetation on bogs might have also played an important role in the hydrological response of peatlands to MWP climate changes.

The last event of sun activity during the Mediaeval Period being potentially recorded in studied bogs is the Wolf solar minimum (ad 1280–1340; Wigley, 1988). Climate cooling at that time was broadly reflected in peatlands across Europe and resulted in water table rises (e.g. Charman et al., 2006; Gałka et al., 2013; Mauquoy et al., 2008; van der Knaap et al., 2011; van der Linden and van Geel, 2006). This minimum may have resulted in intensification of the mass movements in the Flysch Carpathians (Alexandrowicz, 2013; Margielewski, 2006). A distinct rise in the water table ca. ad 1300–1350 (Figure 3) was detected in the Puścizna Mała bog. However, no response has been recorded to this climate deterioration in the Rodna Mountains (north Romania, the Carpathians, 1360 m a.s.l.; Diaconu et al., 2017; Feurdean et al., 2015). There was also no clear signal from the Hrubý Jeseník Mountains (northern Czech Republic, Eastern Sudetes Mountains, 1320–1350 m a.s.l.; Dudová et al., 2013), but it might have been missed by a too low sampling resolution for this part of the core. The contrasting hydrological patterns of peatlands during the Wolf solar minimum in different areas of Central Europe might be partly explained by different intensities of human impact. The peatland investigated in the Rodna Mountains is located in a remote area where human presence in the past was scarce (Diaconu et al., 2017; Feurdean et al., 2015). In contrast to the Rodna Mountains (Diaconu et al., 2017; Feurdean et al., 2015), an increase in the water table in high altitudes linked to the Wolf solar minimum was recorded in the Mauntschas mire in the eastern Swiss Alps (1818 m a.s.l., van der Knaap et al., 2011). However, also in the latter case, a human impact on the vicinity of the mire was identified but was fluctuating in the period of ca. ad 1000–1500 (van der Knaap et al., 2011). In the area of the Orawa-Nowy Targ Basin, human impact increased in the 13th century ad as an effect of the foundation of a Cistercian monastery in Ludźmierz and a settlement in Nowy Targ (Kołaczek et al., 2010; Figure 1). A similar response was registered in the Linje mire (northern Poland), in which the highest water table (ca. ad 1310–1355) was preceded by the development of settlements in its vicinity (Marcisz et al., 2015; Figure 7). These examples show that deforestations or other human activities contributing to vegetation cover impoverishment might have led to the enhancement of rises in the water table during the Wolf solar minimum; however, it is hardly possible to differentiate the role of climate forcing from human impact in the peatland responses.

Bog’s functioning after the drainage

The last two centuries brought the most severe transformation of the Orawa-Nowy Targ peatlands. The peat extraction dramatically intensified, which was connected to the development of a drainage network (Łajczak, 2006). This is manifested in both studied profiles by very low water table levels. During the second half of the 19th and the first half of the 20th century ad, peat extraction on the Puścizna Mała dome progressed only from the west and the north, whereas from the second half of the 20th century ad, cutting accelerated and encompassed the whole bog area. In the case of Puścizna Krauszowska bog, the increase in peat exploitation started no earlier than 1930s (Łajczak, 2006). In both cases, there are no distinct drops in TA-inferred water tables simultaneously with increased peat exploitation, but only some minor DWT fluctuations were detected. Independently, the top part of the profile is already composed of the dry TA community, not sensitive enough to further dry shifts (Amesbury et al., 2016). According to historical data, the periods ad 1872–1876 and ad 1890–1900 were dry, and especially, the former was characterized by prolonged sequences of days without precipitation (http://posucha.imgw.pl/). These periods might have contributed to the drop in the water table (of ca. 7 cm) at ca. ad 1885 (±20 years) in the Puścizna Mała bog. About ad 1967 (±6–7 years), a maximum drop in the water table was registered by the Puścizna Krauszowska bog, and a minor dry peak was also detected in the Puścizna Mała bog ca. ad 1970 (±6 years). In ad 1964, 1969 and 1976, droughts occurred in the area of Poland during summer and autumn seasons (Farat et al., 1995). Hence, taking into consideration age uncertainties in both profiles, the recorded peaks may have been a manifestation of droughts. The recovery of the water table to the level prior to the drought (in ad 1967) took much longer in the Puścizna Krauszowska bog (about 25 years) in comparison with the Puścizna Mała bog (about 10 years). This discrepancy might be a result of different magnitudes of dry shifts (4 cm in the Puścizna Mała profile and 10 cm in the Puścizna Krauszowska profile; hence, the greater the drop, the longer the recovery) and/or it can be linked to differences in drainage network and locality of these bogs. The Puścizna Krauszowska bog is located on the watershed, and in the past, it had a denser network of ditches (Łajczak, 2006). This could make its drainage more effective which in consequence affected the peatland resilience. However, it should be noted that both peatlands studied experienced so intense disturbances that they could not have possibly recovered the past baseline conditions.

Conclusions

The study of environmental change that took place in the last two millennia in the Orawa-Nowy Targ Basin (Western Carpathians) based on the Puścizna Krauszowska and Puścizna Mała bogs revealed different palaeohydrological events recorded by biotic proxies:

Two events of drought between the 4th and the 7th century ad, from which the one from Puścizna Mała (ca. ad 370–480) was parallel to the global cold event at ad 300–600 (sensu Wanner et al., 2011). These dry stages were manifested by an increase in percentages of pollen of P. sylvestris type and substantial decrease in testate amoeba concentrations. It is also possible that, at least in Puścizna Krauszowska, the signal of drier conditions might have been a result of autogenic processes such as formation of hummocks within the coring spot area. Despite the signal of human activity recorded in both bogs during this time interval, the dense forest cover points to low human pressure on the environment, including peatland areas.

An increase in the water table reflected by the Puścizna Mała bog (ca. ad 1300–1350) was parallel to the Wolf solar minimum (ca. ad 1280–1340). During this period, the human-induced deforestation probably enhanced the increase in water table level. Hence, it is rather impossible to distinguish the climatic from anthropogenic influence on the bog’s hydrology during the Wolf solar minimum.

A water table decrease was a possible reaction to summer and autumn drought(s) in the period of ad 1960–1980. During the 19th and the 20th century ad, the peatlands in the Orawa-Nowy Targ Basin were subjected to the highest human impact of the last two millennia. Drainage and peat extraction led to a significant lowering of the water table in the studied bogs; nevertheless, these were still susceptible to dry climatic events.

Footnotes

Acknowledgements

Barbara Fiałkiewicz-Kozieł is acknowledged for giving us permission and full access to the peat cores designated for analyses presented in this contribution. We would like to thank Michał Słowiński and Sandra Słowińska for the preparation of samples for the analysis of testate amoebae, and B. Nowaczyńska for carrying out the laboratory preparation of samples designated for palynological analysis. We are grateful to Bas van Geel and two anonymous reviewers for their linguistic support and critical comments on the previous versions of this manuscript.

Funding

The present research was supported by the National Science Centre (Poland) – grants 2011/01/D/ST10/02579 (PI: Barbara Fiałkiewicz-Kozieł) and UMO-2014/13/B/ST10/02091 (PI: Monika Karpińska-Kołaczek); by the Swiss Contribution to the enlarged European Union – grant PSPB-013/2010 CLIMPEAT; and statutory funds of the Institute of Geoecology and Geoinformation (Faculty of Geographical and Geological Sciences, Adam Mickiewicz University) – research topics WNGiG/2012/S/P-B/017 and subsidy for young researchers –0800000000/505/060/STAT_MN (funds for Piotr Kołaczek, 2015).

References

Alexandrowicz

(2013) Molluscan assemblages in the deposits of landslide dammed lakes as indicators of late-Holocene mass movements in the polish Carpathians. Geomorphology 180–181: 10–23.

Amesbury

Swindles

Bobrov

et al . (2016) Development of a new pan-European testate amoeba transfer function for reconstructing peatland palaeohydrology. Quaternary Science Reviews 152: 132–151.

Bastl

MŠ

techová

Prach

(2009) Effect of disturbance on the vegetation of peat bogs with Pinus rotundata in the Třeboň Basin, Czech Republic. Preslia 81: 105–117.

Berglund

Ralska-Jasiewiczowa

(1986) Pollen analysis and pollen diagrams. In Berglund

(ed) Handbook of Holocene Palaeoecology and Palaeohydrology. Chichester; New York; Brisbane; Toronto; Singapore: John Wiley & Sons, pp. 455–484.

Beug

H-J

(2004) Leitfaden der Pollenbestimmung für Mitteleuropa und Angrenzende Gebiete. München: Verlag Dr. Friedrich Pfeil.

Bond

Kromer

Beer

et al . (2001) Persistent solar influence on North Atlantic climate during the Holocene. Science 294: 2130–2136.

Bond

Showers

Cheseby

et al . (1997) A pervasive millennial-scale cycle in North Atlantic Holocene and Glacial climates. Science 278: 1257–1266.

Booth

Lamentowicz

Charman

(2010) Preparation and analysis of testate amoebae in peatland paleoenvironmental studies. Mires and Peat 7: 1–7.

Bragazza

Gerdol

(1996) Response surfaces of plant species along water-table depth and pH gradients in a poor mire on the southern Alps (Italy). Annales Botanici Fennici 33: 11–20.

10.

Bronk Ramsey

(1995) Radiocarbon calibration and analysis of stratigraphy: The OxCal program. Radiocarbon 37: 425–430.

11.

Bronk Ramsey

(2008) Deposition models for chronological records. Quaternary Science Reviews 27: 42–60.

12.

Büntgen

Tegel

Nicolussi

et al . (2011) 2500 years of European climate variability and human susceptibility. Science 331: 578–582.

13.

Chambers

Booth

De Vleeschouwer

et al . (2012) Development and refinement of proxy-climate indicators from peats. Quaternary International 268: 21–33.

14.

Charman

Blundell

ACCROTELM members (2007) A new European testate amoebae transfer function for palaeohydrological reconstruction on ombrotrophic peatlands. Journal of Quaternary Science 22: 209–221.

15.

Charman

Blundell

Chiverrell

et al . (2006) Compilation of non-annually resolved Holocene proxy climate records: stacked Holocene peatland palaeo-water table reconstructions from northern Britain. Quaternary Science Reviews 25: 336–350.

16.

Christiansen

Ljungqvist

(2012) The extra-tropical Northern Hemisphere temperature in the last two millennia: Reconstructions of low-frequency variability. Climate of the past 8: 765–786.

17.

Clarke

(2003) Guide to Identification of Soil Protozoa – Testate Amoebae. Ambleside: Freshwater Biological Association.

18.

Cugny

Mazier

Galop

(2010) Modern and fossil non-pollen palynomorphs from the Basque mountains (Western Pyrenees, France): the use of coprophilous fungi to reconstruct pastoral activity. Vegetation History and Archaeobotany 19: 391–408.

19.

Davies

Fyfe

Charman

(2015) Does peatland drainage damage the palaeoecological record? Review of Palaeobotany and Palynology 221: 92–105.

20.

Diaconu

A-C

Tóth

Lamentowicz

et al . (2017) How warm? How wet? Hydroclimate reconstruction of the past 7500 years in northern Carpathians, Romania. Palaeogeography, Palaeoclimatology, Palaeoecology 482: 1–12.

21.

Dudová

Hájková

Buchtová

et al . (2013) Formation, succession and landscape history of Central-European summit raised bogs: A multiproxy study from the Hrubý Jeseník Mountains. The Holocene 23: 230–242.

22.

Dudová

Hájková

Opravilová

et al . (2014) Holocene history and environmental reconstruction of a Hercynian mire and surrounding mountain landscape based on multiple proxies. Quaternary Research 82: 107–120.

23.

Ellenberg

Leuschner

(2010) Vegetation Mitteleuropas mit den Alpen: In Ökologischer, Dynamischer und Historischer Sicht. Stuttgart: UTB.

24.

Farat

Kępińska-Kasprzak

Magier

(1995) Susze Na Obszarze Polski W Latach 1951–1990 (Materiały Badawcze IMGW Gospodarka Wodna i Ochrona Wód, Nr 16). Warszawa: IMGW.

25.

Feurdean

Gałka

Kuske

et al . (2015) Last Millennium hydro-climate variability in Central–Eastern Europe (Northern Carpathians, Romania). The Holocene 25: 1179–1192.

26.

Fiałkiewicz-Kozieł

Kołaczek

Michczyński

et al . (2015) The construction of a reliable absolute chronology for the last two millennia in an anthropogenically disturbed peat bog: Limitations and advantages of using a radio-isotopic proxy and age-depth modelling. Quaternary Geochronology 25: 83–95.

27.

Fiałkiewicz-Kozieł

Kołaczek

Piotrowska

et al . (2014) High-resolution age-depth model of a peat bog in Poland as an important basis for paleoenvironmental studies. Radiocarbon 56: 109–125.

28.

Gałka

Miotk-Szpiganowicz

Goslar

et al . (2013) Palaeohydrology, fires and vegetation succession in the southern Baltic during the last 7500 years reconstructed from a raised bog based on multi-proxy data. Palaeogeography, Palaeoclimatology, Palaeoecology 370: 209–221.

29.

Gałka

Miotk-Szpiganowicz

Marczewska

et al . (2015) Palaeoenvironmental changes in Central Europe (NE Poland) during the last 6200 years reconstructed from a high-resolution multi-proxy peat archive. The Holocene 25: 1179–1192.

30.

Gałka

Tantau

Ersek

et al . (2016) A 9000 year record of cyclic vegetation changes identified in a montane peat-land deposit located in the Eastern Carpathians (Central-Eastern Europe): autogenic succession or regional climatic influences? Palaeogeography, Palaeoclimatology, Palaeoecology 449: 52–61.

31.

Gałka

Tobolski

Górska

et al . (2017a) Resilience of plant and testate amoeba communities after climatic and anthropogenic disturbances in a Baltic bog in Northern Poland: Implications for ecological restoration. The Holocene 27: 130–141.

32.

Gałka

Tobolski

Lamentowicz

et al . (2017b) Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae. Quaternary Science Reviews 156: 90–106.

33.

Gaillard

M-J

(2013) Pollen methods and studies – Archaeological applications. In: Elias

Mock

(eds) Encyclopedia of Quaternary Science. 2nd Edition. Amsterdam: Elsevier, pp. 880–904.

34.

Grimm

(1991) Tilia and Tilia Graph. Springfield, IL: Illinois State Museum.

35.

Grosse-Brauckmann

(1974) Über pflanzliche Makrofossilien mitteleuropäischer. Torfe. II. Weitere Reste (Früchte und Samen, Moose u. a.) und ihre Bestimmungsmöglichkeiten. Telma 4: 51–117.

36.

Hanhijärvi

Tingley

Korhola

(2013) Pairwise comparisons to reconstruct mean temperature in the Arctic Atlantic Region over the last 2,000 years. Climate Dynamics 41: 2039–2060.

37.

Hölzer

(2010) Die Torfmoose Sudwestdeutschlands und der Nachbargebiete. Jena: Weissdorn-Verlag.

38.

Juggins

(2003) C2 User Guide. Software for Ecological and Palaeoecological Data Analysis and Visualisation. Newcastle upon Tyne: University of Newcastle.

39.

Koczur

(2006) Importance of vegetation in the Orawsko-Nowotarskie peat bogs to biological diversity in the Polish Carpathians. Acta Agrophysica 7: 383–393.

40.

Kondracki

(1998) Geografia Regionalna Polski. Warszawa: Wydawnictwo Naukowe PWN.

41.

Kowanetz

(1998) On the method of determining the climatic water balance in mountainous areas with an example from the Polish Carpathians. Prace Geograficzne IG UJ 105: 137–164.

42.

Kołaczek

Fiałkiewicz-Kozieł

Karpińska-Kołaczek

et al . (2010) The last two millennia of vegetation development and human activity in the Orawa-Nowy Targ Basin (south-eastern Poland). Acta Palaeobotanica 50: 133–148.

43.

Krąpiec

Margielewski

Korzeń

et al . (2016) Late-Holocene palaeoclimate variability: The significance of bog pine dendrochronology related to peat stratigraphy. The Puścizna Wielka raised bog case study (Orawa-Nowy Targ Basin, Polish Inner Carpathians). Quaternary Science Reviews 148: 192–208.

44.

Laine

Harju

Timonen

et al . (2011) The Intricate Beauty of Sphagnum Mosses – A Finnish Guide to Identification. Helsinki: University of Helsinki Department of Forest Sciences Publications.

45.

Łajczak

(2006) Torfowiska Kotliny Orawsko-nowotarskiej. Rozwój, Antropogeniczna Degradacja, Renaturyzacja I Wybrane Problemy Ochrony. Kraków: W. Szafer Institute of Botany Polish Academy of Sciences.

46.

Łajczak

(2009) Warunki rozwoju i rozmieszczenie torfowisk w Kotlinie Orawsko-Nowotarskiej. Przegląd Geologiczny 57: 694–702.

47.

Lamentowicz

Mitchell

EAD

(2005) The ecology of testate amoebae (Protists) in Sphagnum in North-western Poland in relation to peatland ecology. Microbial Ecology 50: 48–63.

48.

Lamentowicz

Gałka

Lamentowicz

et al . (2015) Reconstructing climate change and ombrotrophic bog development during the last 4000 years in northern Poland using biotic proxies, stable isotopes and trait-based approach. Palaeogeography, Palaeoclimatology, Palaeoecology 418: 261–277.

49.

Lamentowicz

Gałka

Milecka

et al . (2013) A 1300-year multi-proxy, high-resolution record from a rich fen in northern Poland: Reconstructing hydrology, land use and climate change. Journal of Quaternary Science 28: 582–594.

50.

Lamentowicz

Milecka

Gałka

et al . (2009) Climate- and human-induced hydrological change since AD 800 in an ombrotrophic mire in Pomerania (N Poland) tracked by testate amoebae, macro-fossils, pollen, and tree-rings of pine. Boreas 38: 214–229.

51.

Lamentowicz

Obremska

Mitchell

EAD

(2008) Autogenic succession, land-use change, and climatic influences on the Holocene development of a kettle-hole mire in Northern Poland. Review of Palaeobotany and Palynology 151: 21–40.

52.

Langdon

Barber

Hughes

PDM

(2003) 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. Quaternary Science Reviews 22: 259–274.

53.

Lorenc

(2005) Atlas Klimatu Polski. Warszawa: IMGW.

54.

Lubicz-Niezabitowski

(1922) Wysokie torfowiska Podhala i konieczność ich ochrony. Ochrona Przyrody 3: 26–34.

55.

Magny

Arnaud

Holzhauser

et al . (2010) Solar and proxy-sensitivity imprints on paleohydrological records for the last millennium in west-central Europe. Quaternary Research 73: 173–179.

56.

Mann

Ammann

Bradley

et al . (2003) On past temperatures and anomalous late-20th century warmth. EOS 84: 256.

57.

Mann

Zhang

Rutherford

et al . (2009) Global signatures and dynamical origins of the Little Ice Age and Medieval Climate Anomaly. Science 326: 1256–1260.

58.

Manukjanová

Štechová

Kučera

(2014) Drought survival test of eight fen moss species. Cryptogamie Bryologie 35: 397–403.

59.

Marcisz

Colombaroli

Jassey

VEJ

et al . (2016) A novel testate amoebae trait-based approach to infer environmental disturbance in Sphagnum peatlands. Scientific Reports 6: 33907.

60.

Marcisz

Tinner

Colombaroli

et al . (2015) Long-term hydrological dynamics and fire history over the last 2000 years in CE Europe reconstructed from a high-resolution peat archive. Quaternary Science Reviews 112: 138–152.

61.

Margielewski

(2006) Records of the Late Glacial–Holocene palaeoenvironmental changes in landslide forms and deposits of the Beskid Makowski and Beskid Wyspowy Mts. Area (Polish Outer Carpathians). Folia Quaternaria 76: 1–149.

62.

Mauquoy

van Geel

(2007) Plant macrofossil methods and studies: Mire and Peat Macros. In Elias

(ed) Encyclopedia of Quaternary Science. Amsterdam: Elsevier Science, pp. 2315–2336.

63.

Mauquoy

Yeloff

van Geel

et al . (2008) Two decadally resolved records from north-west European peat bogs show rapid climate changes associated with solar variability during the mid-late-Holocene. Journal of Quaternary Science 23: 745–763.

64.

Mazei

Tsyganov

(2006) Freshwater Testate Amoebae. Moscow: KMK.

65.

Meisterfeld

(2001) Testate amoebae. In Costello

Emblow

White

(eds) Patrimoines Naturels. Paris: Muséum National d’Histoire Naturelle – Institut d’Ecologie et de Gestion de la Biodiversité (I.E.G.B.) – Service du Patrimoine Naturel (S.P.N.), pp. 54–57.

66.

Miola

(2012) Tools for non-pollen palynomorphs (NPPs) analysis: A list of Quaternary NPP types and reference literature in English language (1972–2011). Review of Palaeobotany and Palynology 186: 142–161.

67.

Mirek

Piękoś-Mirkowa

Zając

et al . (2002) Flowering Plants and Pteridophytes of Poland, A Checklist, Biodiversity of Poland 1. Kraków: W. Szafer Institute of Botany, Polish Academy of Sciences.

68.

Mitchell

EAD

Payne

Lamentowicz

(2008) Potential implications of differential preservation of testate amoeba shells for paleoenvironmental reconstruction in peatlands. Journal of Paleolimnology 40: 603–618.

69.

Moore

Webb

Collison

(1991) Pollen Analysis. London: Hodder & Stoughton.

70.

Nichols

Walcott

Bradley

et al . (2009) Quantitative assessment of precipitation seasonality and summer surface wetness using ombrotrophic sediments from an Arctic Norwegian peatland. Quaternary Research 72: 443–451.

71.

Obidowicz

(1990) Eine pollenanalytische und moorkundliche studie zur vegetationsgeschichte des Podhale-Gebietes (West-Karpaten). Acta Palaeobotanica 30: 147–219.

72.

Obidowicz

(1996) A Late Glacial–Holocene history of the formation of vegetation belts in the Tatra Mts. Acta Palaeobotanica 36: 159–206.

73.

Obrębska-Starklowa

(1977) Typologia I Regionalizacja Fenologiczno-klimatyczna Na Przykładzie Dorzecza Górnej Wisły. Kraków: Uniwersytet Jagielloński.

74.

Ochyra

Żarnowiec

Bednarek-Ochyra

(2003) Census Catalogue of Polish Mosses. Kraków: W. Szafer Institute of Botany, Polish Academy of Sciences.

75.

Ogden

Hedley

(1980) An Atlas of Freshwater Testate Amoebae. London: Oxford University Press.

76.

PAGES 2k Consortium (2013) Continental-scale temperature variability during the past two millennia. Nature Geoscience 6: 339–346.

77.

Payne

Mitchell

EAD

(2008) How many is enough? Determining optimal count totals for ecological and palaeoecological studies of testate amoebae. Journal of Paleolimnology 42: 483–495.

78.

Poska

Saarse

Veski

(2004) Reflections of pre- and early-agrarian human impact in the pollen diagrams of Estonia. Palaeogeography, Palaeoclimatology, Palaeoecology 209: 37–50.

79.

Reimer

Bard

Bayliss

(2013) IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal. BP. Radiocarbon 55: 1869–1887.

80.

Rydin

Jeglum

(2006) The Biology of Peatlands. Oxford: Oxford University Press.

81.

Staszkiewicz

Szeląg

(2003) Flora i roślinność rezerwatu ‘Bór na Czerwonem’ w Kotlinie Orawsko-Nowotarskiej, Karpaty Zachodnie. Fragmenta Floristica Et Geobotanica Polonica 10: 67–91.

82.

Stockmarr

(1971) Tablets with spores used in absolute pollen analysis. Pollen Et Spores 13: 615–621.

83.

Swindles

Roe

(2007) Examining the dissolution characteristics of testate amoebae (Protozoa: Rhizopoda) in low pH conditions: Implications for peatland palaeoclimate studies. Palaeogeography, Palaeoclimatology, Palaeoecology 252: 486–496.

84.

Swindles

Lawson

Matthews

et al . (2013) Centennial-scale climate change in Ireland during the Holocene. Earth Science Reviews 126: 300–320.

85.

Väliranta

Blundell

Charman

et al . (2012) Reconstructing peatland water tables using transfer functions for plant macrofossils and testate amoebae: A methodological comparison. Quaternary International 268: 34–43.

86.

van der Knaap

Lamentowicz

van Leeuwen

JFN

et al . (2011) A multi-proxy, high-resolution record of peatland development and its drivers during the last millennium from the subalpine Swiss Alps. Quaternary Science Reviews 30: 3467–3480.

87.

van der Linden

van Geel

(2006) Late-Holocene climate change and human impact recorded in a south Swedish ombrotrophic peat bog. Palaeogeography, Palaeoclimatology, Palaeoecology 240: 649–667.

88.

van Geel

(1978) A palaeoecological study of Holocene peat bog sections in Germany and The Netherlands, based on the analysis of pollen, spores and macro- and microscopic remains of fungi, algae, cormophytes and animals. Review of Palaeobotany and Palynology 25: 1–120.

89.

van Geel

Andersen

(1988) Fossil ascospores of the parasitic fungus Ustulina deusta in Eemian deposits in Denmark. Review of Palaeobotany and Palynology 56: 89–93.

90.

van Geel

Aptroot

(2006) Fossil ascomycetes in Quaternary deposits. Nova Hegwigia 82: 313–329.

91.

van Geel

Coope

van der Hammen

(1989) Palaeoecology and stratigraphy of the Late Glacial type section at Usselo (the Netherlands). Review Palaeobotany and Palynology 60: 25–129.

92.

Wanner

Solomina

Grosjean

et al . (2011) Structure and origin of Holocene cold events. Quaternary Science Reviews 30: 3109–3123.

93.

Warner

Chengalath

(1988) Holocene fossil Habrotrocha angusticollis (Bdelloidea: Rotifera) in North America. Journal of Paleolimnology 1: 141–147.

94.

Watycha

(1976) Neogen niecki orawsko-nowotarskiej. Kwartalnik Geologiczny 20: 575–587.

95.

Wieder

Vitt

Benscoter

(2006) Peatlands and the boreal forest. In: Wieder

Vitt

(eds) Boreal Peatland Ecosystems. Berlin: Springer-Verlag, pp. 1–8.

96.

Wigley

TML

(1988) The climate of the past 10,000 years and the role of the sun. In Stephenson

Wolfendale

(eds) Secular Solar and Geomagnetic Variations in the Last 10,000 Years. Dordrecht; Boston, MA; London: Kluwer Academic Publishing, pp. 209–224.

97.

Beilman

Jones

(2009) Sensitivity of northern peatland carbon dynamics to Holocene climate change. In: Baird

Belyea

Comas

et al . (eds) Carbon Cycling in Northern Peatlands (Geophysical Monograph 184). Washington, DC: American Geophysical Union, pp. 55–69.