Paleofloristic and paleofaunistic analysis of Dudváh River oxbow and implication for Late Holocene paleoenvironmental development...

Pišút, P., Břízová, E., Čejka, T., Pipík, R. 2010: Paleofloristic and paleofaunistic analysis of Dudváh River oxbow and implication for Late Holocene paleoenvironmental development of the Žitný ostrov Island (SW Slovakia). Geologica Carpathica, 2010, 61 (6): 513-533.

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Abstract: Žitný ostrov, the largest island of the Danube River (SW Slovakia) was formed to its present-day shape in the Neoholocene period. As a result of increased flood and geomorphological Danube river activity dated to 1378-1528 AD, the lower Dudváh River was abandoned and its alluvium became a part of the Žitný ostrov. Study of Dudváh terrestrialised palaeomeander by means of pollen and macrofossil analysis provides new information about the palaeoenvironments of the Danube Plain. Meander under study was cut-off during the Sub-Boreal period when the land was mostly covered by oak-dominated mixed forest with a notable high frequency of Fagus and Abies. At low-lying depressions, Alnus glutinosa have formed typical alder carrs. The largest decline of the mixed forest occurred during the Sub-Atlantic period. Until the mid-19^th century the region was strongly influenced by shallow groundwater and periodical floods, as reflected by pollen of aquatics and marsh species. Amongst non-arboreal taxa, pollen of Cyperaceae, Brassicaceae/Cuscuta, Poaceae and Apiaceae prevailed. Local successional changes started with i. stage of abandoned oxbow still with influx of moving water, poor in both macrophytes and molluscs, ii. shallow eutrophic oxbow lake with slowly flowing or stagnant water overgrowing with aquatics (Ranunculus subgen. Batrachium, Potamogeton sp., Ceratophyllum demersum etc.) abound with molluscs, iii. an open marsh dominated by Cyperaceae (mainly Carex riparia) with Atriplex prostrata, supporting diverse molluscan and Ostracod fauna. Present-day habitat is a result of landscape changes, which have been associated with draining, intensified agriculture, ruderalisation and spread of invasive species.

Z najstaršej prírodnej histórie Mostnej nivy a Auparku

Pišút, P., 2004. From earlier natural history of the Bridge Island and Aupark. Acta Musei Civitatis Bratislavensis, 16, 2004, s. 47-74. In Slovak, English summary, 12 Figs., 1 Tab., 85 references.

The Sad J. Kráľa (Park of J. Kráľ), also known as Aupark, is a green oasis in the very heart of Bratislava. This paper examines the earliest history of this former floodplain, as it is documented by numerous historical maps, written sources and botanical evidence. Demolition of old Petržalka and successive extensive development of this city suburb meant decline for the territory, once favourite recreation place. But we watch in dismay that even now it is increasingly in conflict with plans of modern developers. Some unknown facts from its natural history are presented here, which emphasize its unique geomorphological, biological, historical and cultural values (see also a table, 12 reconstruction maps and ilustrative figures).
After some of the major floods around 1712, a new mid-channel gravel bar appeared in 500 m wide Danube mainchannel between Bratislava (then Pressburg) and the village of Petržalka (Engerau). Soon it developed into a more stable island by vertical accretion and vegetation-growth. Its position made crossing the river easier and safer. Before long, two bridges led to the island, hence its German name Brücken Au, Bruck Auel (= Bridge Island, B. islet). The traffic from Bratislava across the mainchannel was ensured by a „flying bridge“ (= ferry), whereas fixed bridge led from the island to Petržalka across shallower channel, later known as Höllwasser („Hell´s Water“) or Hellwasser („Clear, light water“). After its destruction by the ice flood in 1740, the wooden pile bridge was re-built into the 270 m long impressive structure. Bank revetment and several groynes were constructed to protect banks and the upstream end of the Bridge Island against floods. Original position of its southern bank where it was in 1751 still indicates a shallow terrain depression in the center of park.
After the construction of the right-side embankment with highway to Vienna in 1770s, Hellwasser channel was cut off and silted up quickly. Eventually, also the 200 m wide Croatian channel (Karlburger Arm) was dammed in 1776-1777. During this period of serious human interventions Brücken Au ceased to exist as an island. The original name fell into oblivion and the territory was colloquially referred to as Au, in der Au (= on the floodplain). In 1776, original floodplain forest was adapted into one of the first public parks in Central Europe, which became known as Aupark.
Botanical data presented in this study are mainly based on the work Flora Posoniensis (1791), written by Stephan Lumnitzer. List of 52 species of lower and higher plants reported from the Bridge Island comprises several plants, nowadays completely missing from here, vulnerable or critically endangered. We may also learn quite a lot about the character of local habitats in 1780s, which were either substantially altered or do not exist here any longer. The core of the island represented mature floodplain forest with dominant willows and Black Poplar (Populus nigra). Large areas of sand bars and banks were covered by incipient stages of floodplain forest and by shrub willows, with Purple Willow (Salix purpurea), Osier (S. viminalis), locally with German tamarisc (Myricaria germanica). Dry, elevated, sandy treeless banks were covered by heliophilous herbs. Among local trees, several had already been planted in the late 18th Century, such as the unique Yew (Taxus baccata) and some of sycamores (Platanus occidentalis).
Disastrous ice flood in January 1809 heavily damaged both public park and Vienna embankment. It also reactivated the Croatian channel, which became reconnected with the Danube after 31 years of siltation. To May of the same year dates back an earthen embankment, encircling the core of Bridge Island in total lenght of 1 447 m. It was built by Austrian corpses to protect strategical approach to Bratislava against progreding French military. In 1825 repair works at the embankment finally began and at the same time connection with the town was established via permanent bridge of boats. This aided further development of the right riverside (= establishment of Aucafé, Arena theatre etc.). In 1830s, damaged floodplain park was rebuilt into its today´s shape of an English park, which provides light, open views of the entire area.
The Bridge Island played an extraordinary role in life and development of modern Bratislava. This study shows that Aupark is not only public arboretum with renewed or re-built historical buildings, but it also represents a precious fragment of the past landscape with well-preserved natural floodplain landforms (= central terrain depression) and artificial landforms (Napoleonic embankment). This values must not be endangered by any of future decisions which might affect this area.