Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 5. (Eger, 1985.)

Domokos Tamás: A vízicsigák diszperzióját meghatározó tényezőkkel kapcsolatos megjegyzések

Malakológiai Tájékoztató 5. Domokos Tamás: A VIZICSIGÁK DISZPERZIÓJÁT MEGHATÁROZÓ TÉNYEZŐKKEL KAPCSOLATOS MEGJEGYZÉSEK NOTES ON FACTORS DEFINING THE DISPERSION OF AQUATIC SNAILS Abstract: The author reviews his observations concerning mainly two species, made during collecting. Water snails, living in flowing medium may help their movement by changing the position of their shells according to the direction of the current. In case of a homogenous substrate there is no factor regulating the orientation and the migration. Sadleriana pannonica favours places with swifter current, while Bythinella austriaca prefers those of slower current speed. The speed of migration of the S. pannonica is cca o,5 mm/min. depending on the surface. B. austriaca lives, probably, in the still border zone adhering to the bottom. Dispersion is specific of the species only in the case of homogenous substrate and of steady current circumstances. It means that the ecologists are to be very cautious when analysing abundance and dispersion as the above conditions are rarely fulfilled.