Cascade Effect of Climate Warming: Snow Duration - Vole Population Dynamics - Biodiversity

Several recent reports have presented evidence indicating a change in arvicolid rodent dynamics from high-amplitude density cycles to acyclic fluctuations at relatively low level. The data come mostly from Northern Europe (>60° N) and indicate that the change is caused by climate warming, most pronounced in the winter. In this report we present data showing similar changes in the dynamics of two vole species, Microtus oeconomus and M. arvalis, in open habitats of Poland (<54°N) over last 25 y. Fairly regular fluctuations observed until early 1990s, subsequently changed to become more erratic. We tested which winter weather factors were most important for successful overwintering of M. oeconomus in Białowieża over 12 years, and how those factors changed over the last half-century according to the data from the local meteorological station. Finally, we demonstrate that the fall in the abundance of small game over the last 20 years has been linked to the decline of vole abundance.