A Debreceni Déri Múzeum Évkönyve 1966-1967 (Debrecen, 1968)

Ötvös János–Kovács Béla: A tiszacsegei holt Tisza és környéke élővilága

János Ötvös and Béla Kovács The flora and fauna of the Tisza backwaters and the region at Tiszacsege In the course of redistributing county areas a considerable part of the Tisza riverside was incorporated in County Hajdú-Bihar. Being aware of its responsibility to collect the fauna and flora of the County, the attention of the Déri Museum of Debrecen was focußed on the river Tisza. The village of Tiszacsege was chosen because of its central location in the riverside region of Hajdú-Bihar, and because there is a large backwater area in the environs of the community. Up to the middle of the 19th century, that is before the river was regulated, the riverside was a sea of marshland and swamps. At the time of spring floods the Tisza left its course, flooded the plain of Hortobágy, joined the Berettyó to inundate even Sárrét; it was in this way that the moorland was spreading all over Kunság and went as far as the town of Szolnok. When river control work was started the long bends were cut short for speeding up the downflow of water, and huge dams were erected along both banks. As a result of this regulation the backwaters and swamps beyond the dams dried up gradually — man settled here, ploughing the land, creating arable soil in the place of swamps. This was the case at Tiszacsege, too. Ancient maps show that Tiszacsege was built in an area between two huge bends. These were cut short during regulation, and the lower end of the dam was erected immediately down the village. The backwaters below the village dried up, vanished altogether to be turned into cropland. The bend above the village became a dead channel after it was cut short, but being at the inner side of the dam, it communicates with the live Tisza in spring, at the time of floods. It was this area we chose as the site of our exploration and collecting work- unfortunately, the backwaters have been drained completely since then. This dead channel is about 3 kilometres, with fine open woodland along both banks. Plant communities of Trapetum natantis, Lemno-Utricularietum, Myriophyllo-Potamentum, Nymphaeetum albo-luteae, and Polygono-Potametum are living in these waters. The banks are fringed by communities of Scirpo-Phragmitetum, Caricetum gracilis, Salicetum tirandrae. Communities of Scirpo-Phragmitetum schoeno-plectetosum occur at both ends of the dead channel S.-Ph typhetosum is found upwards, and S.-Ph.-blycerietosum at the drier parts of the banks. Woodland opens beyond the reed and bulrush of the banks. Reedy and sedgy areas are found at the deeper parts where there is water even in summer. The humid soil of the woods is covered by communities of Alopecuretum pratensis, and communities of Salicetum albae-fragilis occur round the groves. From the water of the dead channel we collected aquatic plants and insects, from the humid soil and trees and shrubs of the woodland, a lot of valuable material for our Museum. The ornithological material was studied in more detail, as the avifaune of the Tisza region is better known. Considering the vagrancy of birds, we made an ornithological exploration not only of the dead channel and the adjacent region, but studied a much larger area, a strip of some 20 kilometres stretching from Tiszabábolna to Tiszakeszi along the middle course, from river kilometre mark 445 to 465. We could distinguish 3 biotopes in this area — the first included the avifauna of areas outside the river dam. The second biotope comprises the birds of the woodlands meadows and orchards in the flood areas and of dead channels

; concerning the number of species, we found a predominance of the song-bird build (Passeriformes), and were able to list 57 species here, not including those flying, migrating or wandering over the area. The third biotope is composed of the colony of spoonbills where the dominating species are Ardea cinerea, Ardeola ralloide, Egretta garzetta and Nycticorax nycticorax. We suggest that this latter be declared a nature conservations area. 20