Měkkýši hradů Sion a Vízmburk – sukcese na znovuobjevených zříceninách [Molluscs of Sion and Vízmburk castles – succession on the reappearance ruins of castles]

Castles Sion near Kutná Hora and Vízmburk near Trutnov were completely excavated 40 and 30 years ago. We can therefore monitor the succession in these localities. In the castle Sion there now live 32 species (with species isolated in this locality Helicodonta obvoluta and Causa holosericea). 12 species living in Vízmburk is also a relatively high number in view of the fact that this castle is completely isolated in spruce monoculture. These castles are indirect evidence of long-range transport of snails by birds and other animals. Both localities represent the long-term ecologic experiment.