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)

and high Na2COg - NaHCOg cor tent. The salt concentration in the groundwater around the pans is 700-4 000 mg/l (MOLNÁR 1976V The pans are in depressions formed by wind at the beginning of the Holocene. These are very shallow waters with maximum depth ranging from 50 to 100 cm. Their surface area is relatively large, between 8 and 35 ha. Three of them have large areas covered with reed, the exception is Szappanosszék, where only small patches of reed can be found. Table 1 provides some information about the chemical features of them after KISS (1975L Kondor-tó is divided into two parts, they are referred to as northern and southern part in this paper. They are merely connected by a channel in the reedbelt. Such a distinction was not used by MEGYERI (1975). He noted that the pans were in natural condition except Kondor-tó, since in its northern basin intensive duck breeding had taken place for some years. Both Szappanosszék and Hattyusszék were in closed basins in 1979, while in Szivósszék a canal was introduced. Sampling Qualitative zoological samples were taken by a plankton net of lOO^um mesh size, from both open and vegetated areas of the pans between 19 78 and 198 6. Monthly*bimonthly sampling was carried out in 1979, when from each pan samples of 15 1 were collected as long as water depth allowed it. However, they are not considered quantitative samples, and they are used only to give estimation of relative abundance. Fig. 1. Map showing position of Fülöpháza (inset) and of the pans ( 1 = Kondor-tó, 2= Szappanosszék, 3 = Szívósszék, 4 = Hattyússzék) Fig. 2. Seasonal changes of some environmental variables in 1979 in Kondor-tó, northern part (a= rainfall, b= water temperature, c= pH, d= conductivity)