A reconstruction of the palaeohydrological conditions of a flood‐plain: a multi‐proxy study from the Grabia River valley mire, central Poland

Abstract

This study investigated the Grabia River valley mire in central Poland to reconstruct its palaeoenvironmental conditions from the Younger Dryas to the present. We analysed sedimentological, biological and geochemical data from the palaeo-oxbow lake and valley mire to identify the principal hydrological trends, especially episodes of high water level. During the Lateglacial and Holocene, the Grabia River had a meandering channel, and its hydraulic parameters and the channel dimensions changed in response to climatic oscillations and vegetation development. We identified phases of high flood intensity and high groundwater level that correlate with regional and supraregional climatic events. The frequency and timing of palaeohydroclimatic oscillations show strong similarities to records from other sites in Poland and the rest of Europe. We show that various analytical methods, namely, pollen, plant macrofossils, Cladocera, Chironomidae, sedimentological, geochemical and radiocarbon data, can be effective tools for reconstructing past hydroclimatic changes in palaeo-oxbow lakes and investigating the effects of past climate changes on river environments. The high sensitivity of the biota, especially Cladocera, to changes in water level permits the reconstruction of palaeoecological changes, especially flood episodes that occurred in the river valley. In particular, the increase in the proportion of sediment-associated Cladocera and pelagic taxa was closely correlated with floods. Through comparisons with the palaeobiological data, geochemical data allowed the identification of humid phases within the fen associated with a rising groundwater table, direct fluvial activity (floods) and alluvial deposition. We also discuss the limitations of palaeohydrological reconstructions based on these proxies, especially on fossil aquatic invertebrates.

The usefulness of subfossil Cladocera remains in Younger Dryas climatic reconstructions in central Poland

“…An increase in fluvial activity during the YD has been widely reported from Polish and European valleys (e.g. Huisink 2000; Andres et al 2001;Starkel 2002Starkel , 2011Borisova et al 2006;Gao et al 2007;Starkel et al 2007Starkel et al , 2015Pawłowski et al 2015b;Petera-Zganiacz et al 2015). The floodwaters may significantly decrease the water temperature in the oxbow lake, as at the Ldzań site.…”

Radiocarbon and lead-210 age-depth model and trace elements concentration in the Wolbrom fen (S Poland)

“…The high value of Fe/Mn ratio between 40 and 55 cm depth corresponds to the lower accumulation rate. It is clearly visible on the age-depth model (from 3045 BC to 155 BC -median age) and may indicate higher water table in that period (Pawłowski et al, 2015(Pawłowski et al, , 2016.…”

Fen ecosystem responses to water‐level fluctuations during the early and middle Holocene in central Europe: a case study from Wilczków, Poland

“…) and peat pools (Korhola ; Pawłowski et al . ). In addition, chydorid species such as G. testudinaria and C. rectirostris are primarily associated with vegetation.…”

“…Such processes have been observed in central Poland valley mires (Pawłowski et al . , b). This is also evident in Wilczków by the appearance (X 1 and X 2 wet stages) and disappearance (Y 1 and Y 2 – dry stages) of Cladocera.…”