European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

This species has shown good recovery across much of its range as a result of numerous conservation and reintroduction programmes. In Europe, numbers are growing and population expansion is expected to continue in the future. As such, this species is assessed as Least Concern for both Europe and the EU 27 Member States.

The Eurasian Beaver (Castor fiber) was once widespread in Europe. However, by the beginning of the 20^th century, overhunting had drastically reduced both the numbers and range of this species. In Europe, only a few isolated sites remained: parts of the Rhône (France) and Elbe (Germany), southern Norway, the Neman River, the Dnieper Basin (Belarus) and the Voronezh Basin (Russia). A series of management measures and reintroductions since the 20^th century have enabled the Eurasian Beaver to return to much of its former range, and there are now several rapidly expanding subpopulations extending from Spain and France across central and eastern Europe to European Russia. Its distribution is thus mapped on this assessment as native (capturing all areas of remnant populations, populations reintroduced from the 19^th century onwards, and that have spread naturally within the native range from both remnant and reintroduced populations). Today, the majority of the European population is found in central and eastern Europe (Wróbel 2020), with subpopulations in western Europe relatively scattered, but growing. The species has become re-established in all countries of its former European range except for Portugal, Italy, and the southern Balkans (Halley et al. 2021), though future range expansions are likely. It is generally a lowland species but occurs up to 1,387 m in France (Poitevin and Quéré 2021)

Outside of the assessment area, the Eurasian Beaver also occurs in Asian Russia, Kazakhstan, Mongolia and China.

By the beginning of the 20^th century, the global population had been reduced to eight subpopulations, totalling approximately 1,200 individuals (Halley and Rosell 2002). Protection, reintroductions and natural spread since the early 1900s have now resulted in considerable population growth across much of the Eurasian Beaver’s historic range. The minimum population estimate of the Eurasian Beaver in 2002 stood at 593,000 individuals (Halley and Rosell 2002), and continued population growth has resulted in the more recent minimum estimate reaching 1,479,863 individuals in Europe (Halley et al. 2021). A review of country-specific population numbers can be found in Halley et al. (2021).

The Eurasian Beaver is one of the largest rodents (15-20 kg, rarely up to 40 kg) and is adapted for a semi-aquatic lifestyle, using a variety of freshwater systems, including rivers, streams, irrigation ditches, lakes, and swamps (Wilson et al. 2016). It generally prefers freshwater habitats surrounded by woodland or scrub, but may occur in agricultural land or even suburban and urban areas (Tattersall 1999, Halley and Rosell 2002). Patterns of recolonisation demonstrate a clear preference for still or slow, laminar water flow if it is available (Nowak 1999, Halley and Rosell 2002, Halley pers. comm. 2006). It is often associated with wetlands containing Salicaceae species (e.g. willows, aspens, poplars) (Piton et al. 2020). 

The Eurasian Beaver lives in family groups of an adult pair, kits and subadults, and can establish territories spanning 1.8-4 km of water bank (Gaywood 2017). It feeds on aquatic and terrestrial herbaceous vegetation and broadleaved woody vegetation. It can construct dams to retain water, create feeding areas (this may be particularly important when terrestrial vegetation is difficult to access), provide safe refuge, facilitate travel and aid the transport of woody material (Gaywood 2017, Mohr Mortensen et al. 2021). They rest in burrows and/or lodges.

The Eurasian Beaver's historic decline was caused by over-hunting for fur, meat and castoreum (a secretion from the scent glands), combined with the loss of wetland habitats. Beaver subpopulations were severely reduced in most countries by medieval times, but the species clung on in marshes and other inaccessible places until the advent of efficient steel traps and accurate firearms in the 17^th century; then, through to the 19^th century, there was a rash of final extinctions for these reasons, combined with the drainage of many of the large marshland areas (all of the European refugia where the species survived, except in Norway, are extensive marshlands).

Today, Eurasian Beaver subpopulations in Europe are expanding rapidly, and there are no major threats of a magnitude likely to cause a decline at the regional level. Competitive exclusion of the native Eurasian Beaver by its American cousin, the North American Beaver (C. canadensis) may be a risk in parts of Finland and northwest Russia, but the mechanisms behind their competition are unclear (Halley et al. 2021) since in other areas, the North American Beaver is ‘losing ground’ to the Eurasian Beaver (Danilov and Fyodorov 2016). In any case, European Union member states are required to control or contain North American beavers as an invasive species. Thus, competitive exclusion is not considered to be a major threat regionally.

Roadkill is an important source of mortality for some subpopulations (Tattersall 1999). Rapidly expanding beaver subpopulations may also come into conflict with humans in some areas, as they can cause damage to forestry and crops, though such damages tend to be less severe than those caused by other species such as deer and voles (Halley and Rosell 2002).

Where populations have recovered well, the Eurasian Beaver is a seasonal game species (Yanuta et al. 2022).

A number of conservation measures have contributed to the species' recovery in Europe, including reintroductions and translocations, hunting restrictions, and habitat protection. It is listed under the Bern Convention (Appendix III) and the EU Habitats and Species Directive (Annex V for the Swedish and Finnish populations, Annex II and IV for all others). Early provision of interpretation and public viewing opportunities as well as education programmes are recommended, as this provides a benefit to the local economy through wildlife tourism, and helps foster positive attitudes toward beavers (Halley and Rosell 2002). Further research into the population trends could be beneficial.