The Eurasian Beaver (idem European beaver) (Castor fiber Linnaeus 1758) is a largest rodent in Eurasia and the second by its size (excluding capybara in the Southern America) in the world belonging to the order Rodentia, family Castoridae. This species is native in Belarus; China; France; Germany; Kazakhstan; Luxembourg; Mongolia; Norway; Russian Federation and reintroduced in the following countries: Austria; Belgium; Croatia; Czech Republic; Denmark; Estonia; Finland; Hungary; Italy; Latvia; Liechtenstein; Lithuania; Montenegro; Netherlands; Poland; Romania; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Ukraine (Batbold et al. 2014). In Finland, the most important is the invasive species North American beaver (Castor canadensis L.). Since its introduction in 1937, the species becomes established here but further naturally spread beyond the place of introduction to Karelia and northwest Russia (Belova 2016). Although the Eurasian beaver appears superficially similar to the North American beaver, there are several important differences (e.g., the Eurasian beaver has a larger, less rounded head; a longer, narrower muzzle; a narrower, less oval-shaped tail and some other morphological negligible differences). These species are incompatible genetically: the North American beaver has 40 chromosomes, while the Eurasian beaver has 48. After number of attempts in Russia to hybridize these two species, the result was one stillborn kit that was bred from the pairing of a male North American beaver and a female Eurasian beaver. The aforementioned factor makes interspecific breeding unlikely in areas where the two species’ ranges overlap. The continuous population of Eurasian beaver ranges from eastern Poland through the Baltic States and European Russia to central Siberia. A large disjunctive population occurs in Norway and Sweden, and smaller scattered ones through the rest of mainland Europe. Although natural spread has contributed significantly to range and populations, the main reason of such expansion were reintroductions (Halley and Rosell 2003; Halley et al. 2012) (Figure 1).
Figure 1. Distribution map of Castor fiber L. (red colour) and Castor canadensis L. (green colour) in Europe (© Halley D.J. and Rosell F. 2002)
It is well-known fact that animals need spatially and temporally varying habitats containing sufﬁcient and available food supply and shelter. Humans adapt environment for their needs from prehistoric times. They throughout the centuries affected the Eurasian beaver, once widely distributed across European countries. Not only direct impact on beaver populations (hunting/trapping) but also forestry activities affected greatly on beaver habitats. Forest logging changes drainage patterns and reduce the carrying capacity of once stable stream systems. Silvicultural practices that eliminate or shorten the deciduous shrub and tree stage of the forest regeneration cycle also had negative impact on beaver populations. Continuing human-induced landscape transformation results in habitat loss, increased isolation between landscape fragments and new disturbance types that challenge population. Due to legal protection and targeted conservation measures including hunting/trapping restrictions, reintroductions and translocations, natural recolonization, land/water protection and habitat restoration, the beaver has made a remarkable recovery. It is an evident example of positive comeback within its range. The species is still under special protection across Europe by a number of international legal acts as EC Habitat Directive (Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora) and Annexes II and IVa as species of “Community interest”, the Bern Convention (Appendix III). Harvesting of analysed species is strictly controlled and, in general, is limited in the most EU countries. Some countries have derogation for beaver management from strict protection set out in the Directive. Beaver can presently be hunted and/or trapped as a game species throughout much of Eurasia including EU member states Sweden, Finland, Latvia, Lithuania and Estonia that are listed in Annex V of the Directive. Considering its status, damage caused to forests and agricultural land (flooding and tree cutting for dam and lodge building and for food) and increase in abundance, beaver role as game animal increase again.
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