Reproductive dynamics of the common toad (Bufo bufo) and the grass frog (Rana temporaria) as one of the key species of their seasonal cycle

The results of research on the reproductive dynamics of the key amphibian species of the Ukrainian Roztochchia are presented. Since reproduction is one of the most important and key stages of the seasonal cycle of amphibians, special attention was paid to this period. We used classic and typical methods of recording reproductive activity of amphibians: route records, searching for dead amphibians on the roads, vocalization methods and installation of temporary protective barriers that prevent amphibians from crossing the road. Therefore, amphibians of the genera Rana and Bufo belong to the species with a sudden type of reproduction. We included representatives of the genera Lissotriton, Triturus, Bombina, Hyla, and Pelophylax to the long-term breeding species. In particular, temporary protective barriers gave us indicative and clear concepts regarding the temporal peaks and troughs of reproductive migrations of the studied amphibian species, as well as the direction of movement to reproductive and trophic habitats. Comparing the beginning of reproductive activity and its course throughout the season, we can see certain differences between the model species B. bufo and R. temporaria, in particular, the choice of breeding ponds, the time of spawning and the period of activity of sexually active individuals. Reproductive activity of the common frog occurs in the first half of March — mid-April. In the second half of April, we caught common frogs on both sides of the barriers, which indicates a “turning point” in the sexual activity of this species. Although the common toad is the first to appear after hibernation, spawning occurs approximately a decade later than that of the common frog but takes a little longer. We believe that such research should be continued regularly and our results will encourage herpetologists to further and long-term research.