Environmental Factors Influencing the Distribution of Land Molluscs of an Oligotrophic Area in Southern Sweden

and breeding experiments. Effects of the calcium content and of the pH value of the foerna upon species number and abundance are demonstrated. It is known that in the leaves of some tree species, Ca citrate and other relatively soluble Ca salts dominate, while others are rich in Ca oxalate. In the breeding experiments, Ca citrate had a considerable, and Ca oxalate a moderate positive effect upon the reproduction of Discus rotundatus (Mull.) and Cochlicopa lubrica (Mull.).