Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 88. (Budapest 1996)

Bajzáth, J.: Plant macrofossils from Hungarian Pleistocene II. Angiospermatophyta in Győrújfalu, West Hungary

From these communities more or less the whole succession of aquatic (backwater) and flood plain vegetation could be reconstructed. I can compare the past vegetation with the modern one around the backwaters of the Mosoni-Duna branch (Figs 25-26). The obligate aquatic species (Characeae, Myriophyllum, Potamogeton etc.) and their communities indicate the starting point of the vegetation succession. These plants must have lived in the broad backwater of the Danube which was cut off the main overdeveloped, meandering river. This water must have been maximum 2 metres deep, rich in nutrients (eutrophic), slightly calcareous (FELFÖLDY 1981, 1990) and getting warm (Fig. 24). Nowadays the dominant plant community is the Potamion on the open water surface. The following reedswamp communities (Phragmition) show the first phase of the filling near the bank. These plants (Typha, Schoenoplectus, Scirpus, Stachys palustris, Oenanthe aquatica etc.) stood in shallow, still water occasionally drying out. In higher places on the accumulated organogenic, reed peat sedge, tall herbs (Carex spp.) swamp communities (Magnocaricion) grew. The water table was shallow and often drying out. These plants such as Carex elata formed tussocks. The plants of relatively lower water-requirement (Thalictrum, Polygonum) formed marsh or swampland community on the wet, open habitats of the flood plain. The first step of the whole organogenic filling was indicated by the swamp forest, alder forest community (Alnion). I found only one pieces of fossil alder. But several typical Carex elongata species were found indicating the alder community. This community stood on the accumulated peat originating from reed and sedge plants. Finally on the same altitude of the highest flood plain alluvial, deciduous, hornbeam forest or mixed deciduous (hornbeam-pine) forest might have grown. This hornbeam forest was very similar to the modern Que reo robori-Carpinetum. This community plays an interesting, unique role in the vegetation of Szigetköz nowadays. The hornbeam-oak forest is between the tipical alluvial hardwood forest (oak-ash-elm) and the climax dry oak forest in wet, but higher habitats. Under the trees there are no elements of the hardwood forest. The characteristic understorey plants belong to the Fagion. Unfortunately I have not found fossils which characterize this forest community. On the higher grounds of the northern area (outside the backwater area) coniferous forest may have existed. Picea abies was very common element of West European interglacial floras. I suppose that the driftwoods, pine and spruce of the coniferous forest may have come from the temporary, later part of this Cromer interglacial (or younger glacial period of the Pleistocene). The water plant associations were very similar in each interglacial, so these edaphic communities are not used for the exact climatic interpretation. We can infer the characteristics of this interglacial climate only in an indirect way. Considering the climatic requirements of both animals and plants, it can be said that this interglacial climate was very similar to the present temperate one, but more humid (JÁNOSSY & KROLOPP 1994). Nevertheless one important question emerges. If the age of the fossil assemblage is Cromer interglacial, then why the tipical, indicator Tertiary elements can not be found in the fluvial deposit? Among the fauna there are extant species indicating the exact age of the assemblage. But we must not exclude the redeposition of the sediment at the top