Some ecological features of amphibians in bogs of the Upper Volga River basin

Specific features of population and biotopic distribution of 8 species of amphibians in peat bogs of Tver Oblast were studied. A network of drainage canals and peat carriers became a main habitat of amphibians in the transformed bogs. The level of water acidity was shown to affect the success of reproduction in the common frog, Rana temporaria, and the moor frog, R. moor. At the same time, water acidity was not a decisive limiting factor for adult individuals of frogs, but it might be a cause of significant egg mortality. The egg mortality was assessed by the percentage of dead eggs just before hatching. The large size of clutches and their aggregations promoted the survival of embryos in their central parts. Temperature of water determined the intensity of frog reproduction at its initial stages.