On the Dynamics of Population of Common Frog ( Rana temporaria ) in the North-West of Russia

Multiannual variations in number on stages of ova, metamorphosing juveniles, youngs of the year before hibernation, yearlings, and mature frogs in a large population of common frog, Rana temporaria , were studied in 1981 – 1997 in the “Kivach” State Nature Reserve (southern Karelia, Russia). A method of estimating of the relative abundance was used to evaluate indices of number on each developmental stage. Many weather parameters were measured and phenological terms of setting in of different stages were recorded annually. In multiple regression, variation in abundance on preceding stage together with fluctuation of weather conditions determined from 56 to 93% of multiannual variance of the abundance of frogs on different stages. Graphic comparisons of observed data with calculated values indicate that regression models were found simulate the multiannual number variations well and few divergences are in result of influence of the extreme values of some established weather factors which were not include in equations. Regulation of the Common frog population dynamics in natural environment is discussed.