Influence of forest exploitation on faunistic complexes of small insectivores and rodents in Eastern Fennoscandia

As a result of long-term monitoring (1958–2017) of the status and dynamics of small mammals’ population in Eastern Fennoscandia we analyzed the general regularities of felling impact on the structure of habitats, ecological features, number and territorial distribution of 11 regional small mammal species. In the course of the fifty-year complex studies, a definite specificity of the trends in changing the number and dominance of small mammals after clear cutting of various types of native forests was revealed. In continuous open clearings a temporary increase in the number of rodents and insectivores and redistribution of species in favor of open stations representatives is observed. The forest clearings are very dynamic by their environmental conditions. Small mammal population structure is influenced by the age and type of felling, configuration and area of cutting, the species composition of the cut down stands. The clearings are characterized by a less stable population of animals compared with mature forests, although the average censuring rate for clearings is higher. It was found that concentrated felling leads to disruption of population reproduction. The total animals number decreases, and the population dynamics is characterized by short sharp rises and long deep depressions. Silvicultural operations at felling significantly affect the nature and speed of successional processes occurring in the biotopic groups of small mammals. Reforestation is characterized by a change of dominants in small rodents’ and insectivores’ communities. In general, the population waves of small mammals in the forest clearings and in pine forests are quite synchronous, although the years of definite peaks and depressions may not coincide. On the basis of modeling the processes of forest exploitation impact on small mammal populations the possibilities of long-term forecasting and prevention of negative anthropogenic impacts were determined.