Dynamics of Mouselike-Rodent Abundance and Rodent Community Structure in Sakhalin

The patterns of structural transformation in forest rodent communities of Sakhalin have been considered using data from long-term comparative studies of two communities of a somewhat similar species composition. An analysis of species abundance dynamics and dominance structure show that the monodominant community structure in northern Sakhalin is characterized by the absence of interannual rearrangements and high stability, with the overall animal number in rodent communities dependent only on the abundance of the northern red-backed vole ( M. rutilus ). The community in the southern part of the island could assume one of the two structural types: the monodominant structure with M. rutilus or the gray red-backed vole ( M. rufocanus ) prevailing or a bidominant structure with both species acting as codominants. The numbers of secondary species vary independently of the numbers of dominant species. Changes in the abundance of M. rutilus and M. rufocanus within the same community are synchronized, whereas the population cycles of these species in the southern and northern communities are not conjugated.