L. Forró - É. Murai szerk.: Miscellanea Zoologica Hungarica 5. 1989 (Budapest, 1989)

Forró, L.: Composition and seasonal changes of the microcrustacean fauna of sodic waters near Fülöpháza (Kiskunság National Park, Hungary)

Composition and seasonal changes of the microcrustacean fauna of sodic waters near Fülöpháza (Kiskunság National Park, Hungary) By L. FORRÓ (Received February 10, 1989) ABSTRACT. 41 species of Cladocera and Copepoda were found in five sodic pans situated in the vicinity of the village Fülöpháza between 1978 and 1986. Most of these species are common in Hungarian sodic waters. Moina salina was found here for the first time in Hungary. Usually, few species dominate in the plankton. A clear seasonal succession was observed in Zooplankton composition. In cold season one of the two diaptomids, Arctodiaptomus spinosus and A. bacillifer, occurred with Daphnia magna. In warm periods two further species of Cladocera, Diaphanosoma brachyurum and Moina brachiata were dominant in companion with these diaptomids. KEY WORDS: Cladocera, Copepoda, seasonal succession, small sodic pans A good deal of the sodic waters in the Carpathian Basin can be found in the Great Hungarian Plain, many of them in the region between the rivers Danube and Tisza. Due to various human activities their number decreased greatly in the last decades. Kiskunság National Park was established in 1975 and it includes the sodic pans near Fülöpháza, too. Zoological studies concerning Hungarian sodic waters started almost 100 years ago, for a review see PONYI (1961) and MEGYERI (1972L Extensive studies have been carried out on the Fülöpháza pans by a team between 1972 and 1974: geology was studied by MOLNÁR (1976L phytoplankton by KISS (1975\ Zooplankton by MEGYERI Í1975\ and zoobentos by FERENCZ (1976L Since 1978 I have worked on the Cladocera and Copepoda fauna of these pans. In 1979 I carried out frequent sampling in order to detect seasonal changes. This paper reports the faunistical results of my studies between 1978 and 1986. The seasonal changes observed in 1979 are outlined. MATERIALS AND METHODS Study sites The sodic pans near Fülöpháza (Kondor-tó, Szappanosszék, Szivósszék, Hattyusszék) 'Fig. D and the sand dunes west of them form the IV. basic unit of the Kiskunság National Park. A detailed description of the national park is given by TÓTH (1979L In this lowland area between the rivers Danube and Tisza in Middle Hungary, the climate is continental with uneven spatial and temporal distribution of precipitation and negative water balance (average annual rainfall is 500-550 mm, lower than potential évapotranspiration of 680- 700 mml. Mean annual temperature is 10-11°C, January is the coldest (-1. 5 2°C) and July is the warmest (21-22°C) month. Mean daily temperature is above 10°C from middle April to middle October. Groundwaters have very slow horizontal current