Tiszadob Floodplain NCA
The wildly romantic aspect of the past, endless waterworld of the wide Plain is known from the works of travellers, historians and authors of the previous centuries. As it was written by Károly Eötvös (1842-1916) ‘... the River Tisza is somehow different from what it once used to be. Since the flood controls, the good old Tisza has been truly present only on the old maps. All his fish, as well as his birds are gone: the fish have swum far, the fowls have flown further.’ The river reaching the plain slows down where the constant alterations of the riverbed and the huge floods have created a diverse landscape. The oxbow lakes are covered by hair-weed carpets, while willows and poplars grow along the banks. Among the wide oxbow bends, the lower reliefs are occupied by tall herb vegetation, whereas on the higher and drier plateaux hardwood forestsstand. This is how the neighbourhood of Tiszadob might have looked 150-200 years before.
1. The past and present of the area
The area expanding over 1.030 ha became protected in 1977. It is situated north of the denominative settlement, Tiszadob, making up a contiguous area along the banks of the River Tisza. Due to sedimentation, the landscape is rather flat. The only dips we can found here are the natural riverbeds left behind by the rivers and the artificial oxbow lakes that were cut off during the flood control. Besides the embankment, the only part emerging from the flat ground is the so called ‘Fisherman-island’ in the middle of the region.
The flood control that was carried out only seven kilometres from the reserve, had drastic effects on the landscape. It was István Széchenyi who initiated the process near the Urkom Forest on the morning of 27th August, 1846. The plan was carried out by Pál Vásárhelyi and was modified by Paleocapa from Venice. Vásárhelyi had hardly lived to see the beginning of the dam construction as he died during the course of that year. The results speak for themselves: bends were cut through at 112 sites, now making up a total of 136.2 km of oxbow lakes. Consequentially, the length of the originally 1419-kilometre-long river section was reduced to 966 km. That, in turn, brought about a decrease in its grade difference from 3.8 cm to 6 cm between Tiszaújlak and Tiszabecs. A 3555-kilomtre-long dyke was constructed which now protects 26,500 km2 against floods. A triplet of monuments emerges in the vicinity of Tiszadob to direct our attention back to this truly amazing enterprise. Right next to the dike stands the statue of Pál Vásárhelyi (1795-1846). Not far from this, we find the obelisk of István Széchenyi (1791-1860) and then comes the third statue, that of Gyula Andrássy (1823-1890), prime minister of the time, who espoused the case.
Later on, when the consequences of the flood control became more and more apparent, scientists began raising awareness about their harmfulness. ‘The irreversible ’success’ of the flood control's results seem to be rather alarming’ said the famous geographer, János Hunfalvy in 1863. ‘Do not construct dikes only, but instead try to work out how to irrigate the soil and the arable lands at times when needed. Otherwise the Hortobágy Puszta will soon resemble the Sahara desert. When planning flood control and the drainage of lakes and ponds, do not only take into account the engineers' drafts but also the opinion and views of naturalists and biologists.’
2. Description and nature conservation of the area
The greater part of the conservation area where the diverse grasslands and forests used to lie, is protected. Due to the regular floods, the area is characterised by a sediment soil poor in humus. As of today, floods still act as a significant environmental factor.
Among the greatest values of the area are the few remnant patches of hardwood groves (Fraxino pannonicae - Ulmetum) growing on the elevated floodplain. This association is of great significance as it survives in its original sites and preserves a typical composition of plant species. These associations have become dominated by ashes due to the changes in environmental conditions, as well as the misuse of forests and the elm-disease of the ’30s. Fortunately, the composition of the association and the proportions have remained untouched. The forest is dominated by very old and huge Pedunculate Oaks. Among these, southern ashes and elm trees stand upright and cast a shadow on the herbaceous layer. The trees decay here standing upright. Thousands of lilies-of-the-valley push their way through the yellow cracks of silt and provide a sweet fragrance among the trees. At other sites, Male-ferns, Lady Ferns and occasionally Ophioglossum vulgatum grow. This is a world of fairies with the orchids. The flowers of the Lesser Butterfly Orchid are greenish-white, while an Epipactis species, the Broad-leaved Helleborine has dark purple flowers. The Sweet Violet is also frequent here. Recently fallen giant trees provide open gaps for the Summer Snowflake. On the sunny forest edges, the large white stars of Chrysanthemum serotinum shine brightly in the autumn. On the sunny sides, lianes such as a vitis species Virginia Creeper, creepers (Parthenocissus sp.), Echinocystis lobata, and the Traveller's Joy creep up the tall trees together with the Berry Catchfly and blackberry (Rubus sp.) below forms an impenetrable and prickly web. Among the trees, we may sometimes come across White or Black Poplars. Some may serve as homes for the Black Stork, a rare bird of these dense forests.
The famous heron colony of the Rákóczi-oak forest has been known for decades. 80-90 pairs of Grey Herons nest in the top of the trees. The nearby oxbow lakes provide them with ample food. The old trees rich in cavities give home to a great number of birds. Beside the species that are frequent everywhere like tits (Parus sp.), the Nuthatch and the Short-toed Tree-creeper, species that are rare on the Plain like the Blue-backed Dove and the Tawny Owl regularly breed here. Some species, including the Black Woodpecker have become frequent only recently. Birds, as well as several bat species, the Wildcat and the Beech Marten can find favourable hiding places in the hollows of the old trees.
On the low-lying floodplains of the conservation area, there are willow-poplar groves (Salicetum albae-fragilis). At certain sites, the sarmentums of various lianes like those of the Dewberry or Echinocystis lobata weave through the trees and shrubs, whereas elsewhere the non-native False Indigo create impenetrable walls. These forests are dense and humid, their damp soils are sustained by regular floods. After the floods, pools and wet patches remain in the dents, therefore both the ground level and the herbaceous layer are poor both in animal and plant species. In the thick vegetation, the Large Amber Snail and the Copse Snail are abundant. In ponds and puddles, the common river snail is frequent. The avifauna in the softwood stands is poorer than in the old hardwood groves. Hydrophilous species are characteristic here. The Mallard is likely to nest in the hollows and cavities of the thick willows, as well as species of varying body sizes find appropriate holes for themselves. The Penduline Tit weaves its elaborate nest on branches bending over the river. The drier shrubs provide breeding sites for hundreds and hundreds of loud Nightingales. The thick, impenetrable forests remain undisturbed, therefore these are preferable habitats for the Wild Boar. The rapid growth of their population presents a problem for nature conservation. The floodplain and the surrounding arable lands are also suitable for these animals.
The oxbow lakes are extremely valuable parts of the conservation area. The so called ‘Szelep’ oxbow lake got cut off from the river before the flood controls in a natural way. Due to its advanced stage of eutrophication, open water surfaces can be hardly seen. And yet, the large Great Spearwort can be found in this association. In the central, deepest parts of the lake the deposited organic sediment forms swimming bogs. They are covered by plants: even the Grey Willow can manage to grow here. Sometimes smaller fragments are torn away from these swimming rafts by the wind and the concomitant waves, which may in turn drift to the shore to 'anchor' there. This series of events demonstrates the process of sedimentation and the formation of swamps and bogs. The surface of the lake is covered by a hair-weed carpet which is decorated by the attractive flowers of the White Water-lily in the summertime. The Frogbit also contributes to the spectacular scene with its tiny white petals, as well as the acquatic Floating Fern. The remaining patches are taken over by the thick stands of the Common Duckweed and the Great Duckweed. The occurrence of the smallest flowering plant, the Rootless Duckweed (Wolffia sp.) was recorded here in 1966. An insectivorous plant, the Greater Bladderwort further enriches the diverse vegetation. In addition, the Water Soldier with its jagged, sharp leaves is also a typical species of these lakes with a high organic matter content. Its stems descend to the bottom of the lake in the autumn to survive the harsh wintertime. The quickly growing Water Chestnut is also worth mentioning. These small oxbow lakes have very thick vegetation and warm up fairly quickly, which allows for a rich fish fauna. Nature itself protects these animals, as in the thick hair-weed vegetation it is almost impossible to catch them. The European Mudminnow that used to be a widespread species in the former swamps of the Plain is of especially great conservation value. It has become rare due to to its shrinking habitats.
The side spared from regular floods and those parts of the 'rescued’ side that are affected only by inland waters have some alkali-like meadows resembling the wooded steppes of the Hortobágy. The Hog's Fennel, Artemisia pontica and at certain sites, Aster punctatus belong to its characteristic species. Among the reptiles, the European Pond Terrapin that can be seen sunbathing on the riparian tussocks, can be regarded as a frequent species. We may also catch sight of the Grass Snake here. The avifauna is represented by a nesting community truly characteristic of swamps. Besides the rails including the Moorhen, the Waterrail and the Coot, the Common Pochard and the Ferruginous Duck, the Reed Warbler, Savi's Warbler, the Purple Heron, the Little Bittern and the Marsh Harrier can all be regarded as common species. A small colony of Black Terns can be observed on the edges of one of the lakes.
The area plays an important role in the lives of the residents of the nearby heron colonies. One can always observe fishing Night Herons and Little Egrets from the look-out towers.
It is conspicuous how uniformly the birds utilize all nesting and feeding resources of the habitat. The southern boundary of the nature conservation area is the 12 km long oxbow lake which was formed during the flood control of the Tisza. Old poplars and ashes surround its splendid shores. The colourful carpets of the characteristic plant associations including species like the White Water-lily, the Yellow Water Lily and the Water Chestnut were severely damaged because of the negligently introduced exotic fish species. Several pairs of geese and Great Crested Grebes live in this habitat. The brilliantly coloured Kingfisher is on the lookout for food mainly consisting of small fish from the branches bending over the lake. The avifauna of certain oxbow lakes is diminishing due to the perishing hair-weed vegetation.
