Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 12. (Eger, 1993.)

SZABÓ, S.: The effect of becoming waterless and experiments of livingplace reconstraction on Monusca living in the soid laces of Upper Kiskunság

The effect of becoming waterless and experiments of livingplace reconstruction on Mollusca living in the soid laces of Upper Kiskunság S. Szabó It is commended to remembrance of my master dr. Andor Richnowszky Abstract: The escape factor of the species is the sudden decrease of waterdepth, increase of pH value, quantity of sodium carbonate value of conductivity. The survival: in the sodic lakes nearly every species forms thin skin or chalky iclusion on its mouth sometimes. Individuals of certain species stay on the surface in latent condition but individuals of other species hide in still humid mud or into the polygonal rents of parched bed. Raising of problem The extremely dry weather of the last, nearly one and a half decade has put to the test the sodic lakes placed on the territory of National Park called "KISKUNSÁGI" (HUNGARY). Our big sodic lakes have shrivelled or temporarily have disappeared because of the permament lack of precipitation. The permamental livingplace reconstruction has been started with return of water artificially by the Directory of National Park "Kiskunsági" on territories number I. and H The water has been brought according to definite order from canal XXXI to the "Halas-tó" (fish-pond) of Apaj-puszta and from the Main Canal "Kiskunsági" to the "Fehérszék" of "Fülöpszállás" in the last three years. In the summer period the territories are kept dry for two months and the rich occured fitomassa is cleared away by mowing. The molluscs - in their death as welle! - are good indicator organisms and suitable for analysis of former conditions and for observation of reconstruction's process. The continuous dry period and the livingplace reconstructional initiations have caused decided difference in coenosis of watersnails living in the sodic lakes of Upper Kiskunság (Szabó, S. 1992 b). These differences are og importance according to order in the biomassa of the snailcoenosis. I have examined the next problems in my researches: - the dispersion, and change of snailcoenosis, - the questions of survival, return and spread, - the methodics of snailbiomassa, - the biomassa of snailspecies, snailcoenosis in the sodic waters. Paralell with the work done in the living-place reconstructional territories I. have done some observations in the territory number III. of National Park "Kiskunsági" at "Kelemenszék", at lake "Kisréti", at "Zabszék" and at "Pipásszék"; in the territory number II: at "Pozsáros" of Kun szentmiklós, at lake "Gyékény" and next to territory number II. at lake "Háromszögi".