Cycles in the long-term population dynamics of the grey red-backed vole (Myodes rufocanus)

Among species Myodes (Clethrionomys) dwelling in Russia long-term population dynamics of grey red-backed vole (Myodes rufocanus) has been the least studied. To fill this gap we constructed the spectra of the long-term cyclicity of the population dynamics of the vole in different parts of its area and investigated them. In addition, we determined the parameters of perennial rhythms and revealed the features of cyclicity and possible geographical patterns of its changes. We also described the invariant parts of the population rhythm spectrum. Data from western (Northern Sweden, Finland and Kola Peninsula), central (Middle Urals, Western Siberia, Eastern Sayan and Baikal region) and eastern parts of the range (Hokkaido Island and Magadan Reserve) were used. When processing these data, we used spectral analysis programs. It allowed us to obtain a visual representation of the entire set of population cycles of Myodes rufocanus, and to compare the periods and powers of harmonic components. The cycles of long-term dynamics in high frequency bands are shown in all studied populations. 9–14-year cycles of population dynamics are found in many populations in middle frequencies, and on some spectra there are more than 20-years periodic components. Population rhythms of M. rufocanus are adjusted to natural cycles such as cyclical changes in climate conditions. Long-term preservation of such population cycles promotes adaptations to the changes in local climate conditions.