Historical development of floodplain site using Mollusca and cartographic evidence
2002
Pisut, P. | Cejka, T. (Slovak Academy of Sciences, Bratislava (Slovak Republic). Institute of Zoology)
We studied subfossil Molluscan assemblages in the Danube river alluvium near Bratislava, Slovakia. The model floodplain site, currently overgrown by alluvial woodland, was produced by lateral and vertical accretion of fluvial deposits between 1780s-1972. In total 1335 specimens representing 2 aquatic and 31 terrestrial taxa were recovered from soil samples. Distribution of subfossil shells and increasing number of species towards the topsoil were in accord with an alluvial sequence and historically documented floodplain stabilisation by woodland vegetation. Three evolutionary stages were recognised in the development of the site, according to archival maps and assemblages of Mollusca: 1. incipient stage of high energy sedimentary environment in literal zone, with herb vegetation or incipient alluvial woodlands (ca 1780s-carly 19th century), 2. stage of stabilised island with mature softwood floodplain woodland of assoc. Salici-Populetum (early 19th century-1880s), 3. stage of Fraxino-Populetum vegetated floodplain (from late 19th century onward), similar to the present vegetation type, after a palacoenvironmental change to-wards relatively drier environment; presumably as a result of the Danube channelisation. Dating of the floodplain, based on biostratigraphy and cartographic evidence, allowed mean vertical accretion rates of sediment deposition to be determined
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