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)
in July caused only 200yuS decrease in conductivity 'Fig- 31. It was less here than in the northern part in all cases and the extent of seasonal variation is roughly half of that in the other basin, 18 species were found here, species number varied from 2 to 9, maximum occurred in early June. Daphnia magna was less abundant here, while Diaphanosoma brachyurum occurred for a much longer time, from early April to late September continuously. Moina brachiata was less important here, it occurred only twice., in May and in September. Besides the frequent Daphnia longispina, Ceriodaphnia reticulata and Alona rectangula , Polyphe mus pediculus was also found here in late April. Three diaptomids and four cyclopias composed the copepod fauna of this pan. Mixodiaptomus kupelwieseri appeared in April. Both A. spinosus and A. bacillifer occurred in this pan. A bacillifer and A. spinosus were collected from spring to middle June and from early June throughout the year, respectively (Fig. 8). Of the four cyclopoids, M. viridis was the most abundant one here, too, but only for a shorter period. Szappanosszék was the most sodic of the pans in 1979, it was completely dry in September. Water temperature was 13.9°C as early as in March and the maximum, 30.2°C was measured in late July. The pH varied between 9. 35 and 10. 31, conductivity was high already in March, 15 740^uS, maximum was 83 300,uS in June. The rainfall in June resulted in a sharp decrease in conductivity, afterwards it increased again (Fig. 4 1. These data show that the pan was extremely sodic in 1979, this is reflected in the microcrustacean fauna, too. In 1979 merely four species occurred here, but two of them, Daphnia magna and Megacyclops viridis were represented by one specimen. Some years later, in 1985 and 1986, when conductivity was lower (about 10 OOO^S before drying outl, these species were more abundant, and Macrothrix hirsuticornis also occurred. In 1979 the dominance of three species, Moina b rachiata, M. salina and Arctodiapto mus spinosus indicates high salinity and alkalinity values in this pan. The occurrences of these species are shown in Fig. 9, Szívósszék was the least sodic pan, changes in water temperature were similar to that of in Szappanosszék. The smallest pH and conductivity values were measured in this pan, pH changed between 8. 1-9. 85. In spite of the feet, that the pan dried out in October, conductivity fluctuated only between 1060-2300^5. It was gradually increasing throughout the year, the rainfall in June caused very small decrease (Fig. 5). Both the maximal value and the extent of seasonal variation was the smallest in this pan. The greatest number of species, 18 Cladocera and 12 Copepoda, occurred in this pan in 1979. The species number in late March was the greatest here (17 speciesl. The occurrences of abundant Cladocera species are similar to those of in Kondor-tó, southern part. The copepod fauna is also similar, the same three diaptomids occurred here as in the southern basin of Kondor-tó. However, A. spinosus played here an insignificant role, it was found on two occasions only, A. bacillifer was more important (Fig. 101. All these facts, particularly the decline of A. spinosus refer to fundamental changes in the chemistry of this pan. Hattyússzék is the smallest one of these pans, it dries out each year. It was the warmest pan, temperature varied betwe-en 1. 4-31. 6°C. In March it was 14°C. Both pH and conductivity showed great fluctuations 'Fig. 61, pH varied between 8.47 and 10.41. Conductivity changed from 2700 to 46 500 ^S between March and June, considerable decrease was measured after the rainfall in .Tune. Thereafter the pan was dry. 22 taxa occurred in Hattyússzék in 1979. The number of species varied between 2 and 17, with a maximum in early May. The composition of microcrustacean fauna reflects both the sodic and astatic nature of the pan (e. g. occurrence of A. spinosus , on the other hand the occurrence of Branchinecta ferox and Daphnia atkinsonil Arctodiaptomus bacillifer occurred from February to late June, A. spinosus was found from middle March until there was water in the pan. This latter species was the only one that occurred in the sample before the pan dried out 'Fig. 111.
