According to the latest monitoring counts, the number of European beavers in Finland totals a minimum of 2,400 individuals and the total number of North American beavers is 4,000 individuals. While the North American beaver population has declined somewhat, there is a risk that the species will spread westwards into areas populated by the European beaver.
The European beaver, which was once the native beaver species in Finland, was hunted to extinction in the latter half of 1800s. To restore the beaver to Finland, both the European beaver and the North American beaver were introduced in Finland in the 1930s.
Later, it became evident that these two very similar species were probably competitors and could not, therefore, coexist for any length of time. The North American beaver may displace the European beaver if their territories overlap. To safeguard the existence of the European beaver, immediate steps should be taken to halt the spread of the North American beaver westward. The North American beaver is a non-native species and has been classified as an invasive species in Finland’s National Strategy on Invasive Alien Species.
The area of distribution of the European beaver comprises most of Satakunta, the municipalities of Parkano, Ikaalinen and Sastamala in the province of Pirkanmaa, part of Etelä-Pohjanmaa, and sections of coastal Ostrobothnia. The North American beaver population is at its densest in Pohjois-Karjala and the provinces of Etelä-Savo and Pohjois-Savo. The population appears to be spreading westwards.
The size of the beaver population is monitored by carrying out nationwide counts of active winter lodges at three-year intervals. Luke evaluates the size of beaver populations on the basis of these counts. Luke also collected beaver skulls for species determination, particularly in Pirkanmaan and Etelä-Pohjanmaa. In these provinces, DNA samples are also taken in order to establish the precise distribution of both species. In addition, Luke participates in other research projects on beavers, by providing guidance to doctoral students, for example.
The monitoring of both species and determining their precise distribution area is highly important to the removal of the North American beaver from critical areas and preventing it from spreading to areas populated by the European beaver. Among other things, such data are used by game management authorities when deciding on hunting quota and licences for European beaver.
Photo on top of the page: Petri Timonen / Luke