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)
1979 was a rather dry year, the rainfall was only 385 mm. Zoological samples were collected between 30 January and 18 December chemical samples were taken between 22 March and 15 October. RESULTS AND DISCUSSION Faunistical aspects In the sodic pans at Fülöpháza forty one microcrustacean species (one anostracan, 27 Cladocera and 13 Copepoda^ were found between 1978 and 1986 (Table 2L Moina s alina Daday was recorded for the first time in Hungary, a detailed account of this record was given elsewhere (FORRÓ 1988L There was a great variation in the number of species recorded in the individual pans. Szivósszék had the greatest number, thirty three species occurred here, while the minimum, seven species were found in Szappanosszék. Twenty - twenty two species were recorded in the other three pans (Table 2L The great difference between maximum and minimum values is very likely due to the difference between the salinity values of these pans in 1979 (for a comparison of conductivity values see Figs 4 and 5L MEGYERI (1975) reported the occurrence of-sixteen species in these pans between 1972 and 1974. He found the maximum number of species in Kondor-tó, and the minimum in Szappanosszék. The reason why a greater number of species is recorded in the present study may be the frequent sampling in 1979 and the changes'in the chemistry of Szivósszék. This pan was rather sodic in the time of MEGYERI's work, while in 1979 the conductivity was rather slow, it indicates a sharp decrease in salinity; the pan has actually lost its sodic character. MEGYERI (1975^ found 11 Cladocera and 4 Copepoda species in these pans, most of them are widely distributed in Hungarian sodic waters. In my samples many species were found which are typical of littoral areas of various lakes. This is indicated by the much greater number of cyclopoid species s too. The number of chydorid species has also increased. Another interesting point is the occurrence of Polyphemus pediculus in Kondor-tó, which is the fourth record of this species in sodic waters in Hungary. Four species occurred in each pan: Daphnia magna, Moina brachiata, Macrothrix hirsuticornis and Megacyclops viridis . Arctodiaptomus spinosus was very abundant in each season, it occurred also in Szivósszék, however, it was not found in the northern basin of Kondor-tó. In this latter pan A. bacillifer was recorded, and it also appeared in other pans except for the highly sodic Szappanosszék. Seasonal changes In the northern part of Kondor-tó water temperature varied from 0. 8 to 2 8. 4°C; in middle March it was above 10°C in May. it exceeded 20°C and dropped below this value only in October. The pH fluctuated between 8. 42 and 10. 19, the maximum value occurred in May probably due to the photosynthetic activity of an algal bloom. The conductivity almost continuously increased up to late autumn, from 1940 ^S to 3920 ^S. In July it decreased with 600^uS, which is certainly the effect of a rainfall (Fig. 21. 17 Cladocera and 5 Copepoda species were found here. The maximum number of species, 13, was observed at the end of April, with the majority of species in samples from vegetated areas. Arctodiaptomus bacillifer was collected at all occasions, while A. spinosus did not occur in this pan. Three Cladocera species accompanied with A. bacillifer during the year. Daphnia magna in the cold season, in winter, spring and in late autumn again, Diaphanosoma brachyurum occurred in summer and Moina brachiata was abundant from August to middle October (Fig. 71. Macrothrix hirsuticornis was also frequently found in summer samples. Of the cyclopoids, Megacyclops viridis was the most frequent, occurring in almost all samples, from vegetated areas. In the southern part of Kondor-tó temperature and pH were similar to that of measured in the northern part, with a bit smaller values here. The differences in conductivity were much greater between the two parts. It varied from 1220 to 2200 ^iS, and the rainfall
