Vízügyi Közlemények, 2002 (84. évfolyam)
2. füzet - Csányi B.-Juhász P.-Tyahun Sz.: A ráckevekei-soroksári Duna makroszkopikus vízi gerincteleinek vizsgálata
190 Csányi В. -Juhász P.-Tyahun Sz. Schmedtje U.-Kohmann F.: Bestimmungsschlüssel für die Saprobier-DIN-Arten Macroorganismen. Bayerische Landesamt für Wasserwirtschaft, Informationsberichte Heft. 1992. Steinmann, H:. Tevenyakúfátyolkák, Vízifátyolkák, Recésszárnyúak és Csőrös rovarok Raphidioptera. Megaloptera, Neuroptera, Mecoptera. In: Magyarország Állatvilága. Fauna Hungáriáé. 13. 1967. Tyahun. Sz:. Populationsdynamische Untersuchungen der Mesofauna in den Laichkrautbeständen des Donauarmes von Soroksár. -Opusc. Zool. Budapest XIII, 1—2. 1977. Vepsäläinen, K.—Krajewski, S.: Identification of the waterstrider. Gerridae. nymphs of Northern Europe. — Ann. Zool. Fennici. 1986. Varga A.-Csányi В.: Vizicsiga fajok elterjedése magyarországi folyókban az elmúlt évtized vizsgálatai alapján I. Fol. Hist.-nat. Mus. Matr. 1997. Varga A.-Csánvi В.: Kagyló fajok elterjedése magyarországi folyókban az elmúlt évtized vizsgálatai alapján II. Mollusca Bivalvia.. Fol. Hist.-nat. Mus. Matr. 19981999. Wallace I. D. Wallace В. Philipsen C.N.: A key to the case-bearing caddis larvae of Britain and Ireland. Scient. Pubis. Freshwat. Biol. Ass. 1990. * * * Investigation of the macroscopic invertebrates of the Ráckeve-Soroksár Danube arm By Dr Béla CSÁNYI PhD.. Péter JUHÁSZ and Dr Szabolcs TYAHUN biologists The study describes the state of the fauna of the Ráckeve-Soroksár Danube (RSD) arm. Three different hydrobiological surveys were carried out. The first one was made in the framework of the survey of the state of the River Danube, supported by the Federal Environmental Ministry of Germany. Two years later qualitative and quantitative analysis of the fauna was carried out in RSD in the framework of a programme on searching rehabilitation options. In June 1998 a quantitative macrozoobenthos study was carried out, which was followed in September with a qualitative survey identifying the presence or absence of the species. Finally in August 2001 the macrozoobenthos survey of the furthest downstream sections of the RSD was carried out in the framework of the International Danube Expedition, which was organised by the International Commission for the Protection of the Danube River (ICPDR). Results of this latter survey completed the data base on the fauna of the RSD. On the basis of the results of the first survey in 1995-96 it was found that the group Mollusca were very rich in species (Table II.). A total of 15 water snail and 7 mussel species were found. A characteristic increase of the communities of Dreissena polymorpha towards the downstream was identified. Of the total number of leach species the many of those characteristic to standing waters were found only in the RESD but not in the neighbouring Danube arm (Erpobdella nigricollis, Haemopis sanguissuga, Hemiclepsis marginata. Theromyzon tessulatum). Among the higher-order crustacea two taxa were found in the RSD only (Argulus foliaceus, Niphargus hrabei). The first one is a parasite of crap-like fish, while the second one is characteristic standing waters and marshlands. Most of the insects were those characteristic to sluggish or standing waters. The exception was the larva of an Ephemera specie, which was found in the vicinity of the Kvassay-gate (the inlet gate from Danube), thus was of danubian origin. A general conclusion is that macrozoobenthos taxa were increasing towards the downstream. On the basis of the samples collected in August 1996 the water quality class was defined as Class 111. В in each section investigated. This means that a rather uniform organic-material input is present along the entire RSD (Table III.). The quantitative data of some of the species collected in 1998 are shown in Figures 1—5.
