Abstract
The vegetation development of the East Bohemian lowland is poorly known, despite its interest for archaeology. One reason is that suitable sites are difficult to locate due to the long history of human occupation modifying the natural vegetation. The only site studied in any detail is Na Bahně. Pokorný et al. (Citation2000) described the local vegetation development of the site, whereas the hitherto unpublished regional pollen stratigraphy is presented here.
Site details
The alder-carr fen Na Bahně (240 m a. s. l., 50° 11’ 51.4’’ N, 15° 57’ 32.9’’ E, 1 ha) lies below the youngest, Würmian terrace in a floodplain, 150 m from the Orlice River, about 8 km east of the Elbe River. Mikyška (Citation1926) and Klimešová & Klimeš (Citation1996) described the local fen vegetation as alder carr (Alnion glutinoso-incanae). The floodplain has grasslands on mineral soils (flood loams) with patches of alder carr on peaty soils. The uplands adjacent to the floodplain are mostly arable land, with deciduous-forest remnants of Melampyro nemorosi-Quercetum, Molinio arundinaceae-Quercetum, Vaccinio vitis-idaeae-Quercetum, and Luzulo-Fagetum in the wider region (Neuhäuslová et al., Citation1998). Mean annual air temperature is 7.8 °C, and annual precipitation is 602 mm (AD 1901–1950 average, Nový Hradec Králové Meterological Station, 8.5 km east of the study site; Vesecký, Citation1961). The peat sequence was collected with a Russian corer 5 cm in diameter in early spring 1997 by Petr Pokorný and his crew.
Sediment description
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0–115 cm: woody coarse-detritus peat
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115–195 cm: coarse-detritus and moss peat
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195–330 cm: woody coarse-detritus peat
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330–420 cm: plastic clay
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420–425 cm: sand
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425–438 cm: plastic clay
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438–475 cm: plastic clay with plant detritus
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475–500 cm: unsorted coarse sand and gravel
Dating
Three levels were radiocarbon dated at the Radiocarbon Dating Laboratory, Department of Quaternary Geology, Lund, Sweden. Results are:
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111 cm (2 cm thick): 890±90 BP (Alnus wood; LuA-4528; AMS)
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330 cm (1 cm thick): 1440±70 BP (Alnus wood; Lu-4529; gas decay counting)
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450 cm (1 cm thick): 2020±110 BP (Alnus wood; LuA-4551; AMS)
Interpretation
shows the results. Zone NBR-1 shows a mostly forested floodplain and moderate human impact. Zone NBR-2 shows some forest expansion (Quercus, Carpinus, Ulmus), likely starting in the Migration Period. Zone NBR-3 indicates some deforestation (Abies and deciduous trees) and increased crop cultivation. Zone NBR-4 shows marked deforestation, grassland formation in the floodplain, and extensive crop cultivation in the uplands. Zone NBR-5 records a shift in crop cultivation from Cannabis/Humulus to Secale.
Figure 1. Percentage pollen diagram from Na Bahně site. Only selected pollen taxa are shown.
Acknowledgements
This project was supported by the Grant Agency of the Academy of Sciences of the Czech Republic, project no. IAAX00020701.
Related Research Data
References
- Klimešová , J. and Klimeš , L. 1996 . Vegetace přírodní památky ,,Na bahně“ po 70 letech (Vegetation of the Natural Reserve ,,Na bahně“ (E. Bohemia, Czech Republic) after 70 years) . Příroda , 5 : 147 – 157 . (in Czech)
- Mikyška , R. 1926 . Reservace “Na bahně” u Bělče nad Orlicí na Královéhradecku (La végétation de la tourbière “Na bahně” de Běleč nad Orlicí près de Hradec Králové (Tchécoslovaquie)) , Vol. 50 , Praha : Nat. Sci. Fac. Charles Univ. Spisy Vyd. Přír. Fak. Karlovy Univ . (in Czech)
- Neuhäuslová , Z. , Moravec , J. , Chytrý , M. , Sádlo , J. , Rybníček , K. , Kolbek , J. and Jirásek , J. , eds. 1998 . Mapa potenciální přirozené vegetace České republiky 1 : 500 000. (Map of potential natural vegetation of the Czech Republic 1 : 500 000) , Prague : Academia Ed . (in Czech)
- Pokorný , P. , Klimešová , J. and Klimeš , L. 2000 . Late Holocene history and vegetation dynamics of a floodplain alder carr: A case study from eastern Bohemia, Czech Republic . Folia Geobot , 35 : 43 – 58 .
- Vesecký , A. 1961 . Podnebí Československé socialistické republiky. Tabulky (Climate of Czechoslovakia. Tables) , Prague : ČHMÚ . (in Czech)