Fehér-szik (alkaline lake) of Tiszavasvár NCA
1. The past and present of the area
The Fehér Szik lies along highway 36. It is located 4 km to the east from Tiszavasvári. 165 ha of the highly valuable area have been protected since 1977. The area was already categorized as a marshland during the 1781- 89 military mapping. The Fehér Szik is characterized by loess soil in a valley without an outlet and is surrounded by hills. Its geological formation dates back to the quaternary. On the basis of its plankton samples, it was Jenő Daday who, at the beginning of the 20th century, emphasised the hydrobiological importance of the area. Since it is surrounded by hills from all sides and has no outlet, the water balance of the lake is absolutely dependent on precipitation. It was most likely formed during the postglacial period with a presumably much lower ground water level. Due to the rising water table, sodification took place later in the basins that formed during the postglacial period. During the drying up of the lake, sodium carbonate accumulated on the surface. For centuries, local residents used to gather the sodium carbonate and even a natron plant was established here in the 18th century. The saline lake covering over 100 ha is supplied by precipitation and groundwater.
Earlier, the water level followed the alternating changes of wet and arid periods. In some years, the lake dried out completely and by the end of the summer the water receded to the deepest parts of its basin. The constantly fluctuating water-levels sustained the process of sodification thus preventing the habitat from becoming homogenous. The intensive measures to drain inland waters during the mid-60’s upset the water balance of the lake. Since 1976, the inland waters have been drained off into the lake bed, as a result of which the lake does not dry up any longer.
2. Description and nature conservation of the area The changes in water conditions have lead to fundamental transformations of vegetation boundaries. Together with the rising water levels reed species (Phragmites sp.) have advanced towards the margins, driving out the halophyte Maritime Bulrush of its original habitats, the salt marshes. The Maritime Bulrush, in turn, has taken the place of the alkali meadows and the alkali desert associations. This area is now dominated by reeds including separate patches of Common Bulrush and Lesser Bulrush. Today, the plant species once characteristic of the unique community covering the bottom of the saline lake (Heleochloa sp. and the Barilla Plant) occur only during years of drought and even then only in small numbers.
The avifauna as well as the diverse habitats of the saline lake are of the highest value. According to the surveys, 41 bird species nest here. Although both species richness and abundance have been on the increase since the increase of the water-level, the rare species of the saline lake have either disappeared or become scarce. No sooner does the ice melt than the first harbingers of spring, the Lapwings appear. More and more birds occur with the warming weather. On their way to their nesting places, hundreds of geese, swans, ducks (Anatidae) and Cranes and various other waterbirds arrive searching for food and a temporary resting place only to move on a few days later, physically strengthened. However, not all the birds leave the lake. For instance, species such as the Lapwing or the Redshank stay. The Great Crested Grebe or the Little Grebe can easily be observed from the look-out tower that is situated on the western part of the lake while the deep, booming sound of the Bittern can be heard from the reeds. It is the Coot and the Moorhen that can be seen in the greatest numbers and the most frequently. Avocets may nest in the ‘vakszik’ patches that have gone dry. The Marsh Harrier is a characteristic nesting bird of prey. Among the songbirds, Reed Buntings are abundant here, together with the Bearded Tit in bulrush patches. In late summer, large groups of Spoonbills, Little Egrets and Grey Herons forage here. During the autumn migration, smaller or bigger flocks of White Storks and occasionally Black Storks appear in this area. In October, Mallards, Teals and later Bean Geese and White-fronted Geese arrive in large numbers.
The footprints of Red Foxes or Eurasian Badgers can be observed in the soft mud on the shore whereas ‘the strongholds’ of the Muskrat made up of water weeds emerge from the aquatic vegetation.
Admission to the area is strictly controlled during the breeding period, but is open to visitors before and after the breeding season.
