Eurasian Beaver: Castor fiber

PRODUCT HIGHLIGHTS

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.

References

Batbold, J., Batsaikhan, N., Shar, S., Amori, G., Hutterer, R., Kryštufek, B., Yigit, N., Mitsain, G. and Palomo, L.J. 2008. Castor fiber. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>.

Bau, L. M. 2001. Behavioural ecology of reintroduced beavers (Castor fiber) in Klosterheden State Forest, Denmark. MSc Thesis, 82 pp. Available at: http://www.sns.dk/natur/baever/links/Castorfiber.pdf.

Belova, O. 2016. Management of Beaver Population in the Baltic Sea Countries – A Review of Current Knowledge, Methods and Development Needs. Interreg Baltic Sea Region, WAMBAF, 37 pp.

Fauna of Lithuania. 1988. Mammals [Lietuvos fauna. Žinduoliai]. Vilnius, Mokslas, 295 pp.

Zurowski, W. and Kasperczyk, B. 1986. Characteristics of a European beaver population in the Suwalki Lakeland. Acta Theriologica 31(24): 311-325.

Halley D.J. and RoseIl, F. 2003. Population and distribution of European beavers (Castor fiber). Lutra 46 (2): 91-101.

Halley, D.J., Rossel, F and Saveljev, A.P. 2012. Population and Distribution of Eurasian Beaver. Baltic Forestry 18(1): 168-175.

GALLERY REFERENCES:

1) http://www.naturephoto.lt/rusis/upinis_bebras-castor_fiber/ziurimiausios
2) Figure 3. Aspen Populus tremula L. partly (a)
3) and fully (2) felled by beaver: teeth marks (©Olgirda Belova);
4) Figure 4. Beaver lodge in the mixed spruce-deciduous forest (©Olgirda Belova);
5) Figure 5. Forest block and forest road flooded by beaver (©Olgirda Belova)

ID&ECOLOGY

The beaver is the semi-aquatic species and largest rodent in Europe (Figure 2). They are adapted to freshwater systems, including rivers, streams, irrigation ditches, lakes, and swamps surrounded by woodland, but may occur in agricultural land or even suburban and urban areas. Beavers are selective but often opportunistically colonize wetlands. Although beavers prefer natural water bodies (overgrown with woody vegetation and herbs and with steep banks, one third of beaver sites), the most preferable habitats are drainage ditches. Stream gradient is important because steep gradients create the potential for disrupting their dams during high-flow events.

Figure 2. The largest rodent in Europe: Eurasian beaver Castor fiber L. (©Romualdas Barauskas, NaturePhoto)

Eurasian beavers weight on the average 20 kg (15-26 kg) (Fauna of Lithuania 1988) but can reach 35 kg (Zurowski and Kasperczyk 1986; Bau 2001). The sexual dimorphism in size and appearance is rather negligible. The colour of the fur varies from greyish brown to black brown. The thick, strong and waterproof fur helps insulate the beavers against the cold weather in the water or on dry land. When surrounded by air, the beaver is able to maintain a normal body temperature at ambient temperatures below 20°C. Above this temperature, it becomes hyperthermic. Beaver uses its broad and scaly tail as driving power, manoeuvring, diving while swimming; moreover, the tail assumes a function in regulation of body temperature, body energy reserve and defence against enemies (using it as “tail slapping”). Other adaptation to semi-aquatic lifestyle are eyes, ears and nostrils placed high on the head so they can maintain vigilance when swimming. The nostrils have special muscles that close the nose tightly when diving. Beaver’s hind and front feet have five digits with claws. The hind feet are webbed and the fourth claws form a comb, used for grooming. Beaver teeth are suited to this diet having large, curved incisors that never stop growing: the pair on the upper and lower jaws form curved blades that chisel through wood as hard as rock maple and are perfectly designed for felling trees (Figure 3).

Figure 3. Aspen Populus tremula L. partly (a) and fully (2) felled by beaver: teeth marks (©Olgirda Belova)

Beavers are true herbivores, and have specialized digestive system. Colonies of microorganisms in their intestines digest up to 30% of the cellulose from the woody food they eat. Beavers do not actually eat wood per se, only the cambium, a soft tissue close to the surface in which new wood and bark grow. To extract the most needful nutrients from their high-fiber diet, beavers eat everything twice when food supplies are low, a practice called coecotrophy (the kind of coprophagy, specifically refers to the ingestion of the paste-like caecal faeces for nutritional purposes as in lagomorphs). Beavers actually pass food through their entire digestive tract twice, eating the gelatinous, caecal substance that comes out of its anus the first time through. Double-digested beaver faeces look almost like pure sawdust. It is the main source of additional proteins, amino acids and, furthermore, the beavers can make use of the vitamins, mainly ones of the B-group as well as vitamin K, produced by bacteria.

The importance and share of plant species in the beaver diet depend on the season, habitat conditions and species occurrence. In summer, animals prefer herbaceous vegetation, growth of trees and shrubs and leaves. There have been described 86 tree species and 149 herbs consumed by beavers (Fauna of Lithuania 1988; Heidecke 1984, 1989; Dvorak 2013; Belova 2006). In non-growing period, they feed on tree bark, twigs and water plants. During the growing season, beavers consume mainly water plants and plants on the banks of water bodies or farm crops. The share of tree species represented in the diet increases at the end of the growing season (October-November) when beavers store food caches underwater for winter and use woody material for building activities. Food caches reach up to 10 m2 and more. However, beavers could not store food caches consistently if winters are comparatively mild. The most preferred species are aspen (Populus tremula L.), willows Salix spp., also ash (Fraxinus excelsior) but, if there is a lack of these species, beaver consumes oak Quercus spp., birch (Betula spp.), hazel (Corylus avellana L.), lime Tilia spp., viburnum (Viburnum opulus), European white elm (Ulmus laevis Pall.). Beavers need not only deciduous species but also coniferous ones. Previously, it was considered that a pine is the indicator of starvation; however, beavers select young pines and on occasion, cut a whole plantation (Fauna of Lithuania 1988; Belova 2006). Beavers select trees of the diameter of stem up to 15-20 cm. They cut more thin trees straight away while thicker trees are gnawed around the stem. Beaver use thee branches and stems for reconstruction of their dams and lodges or for building new. In drainage ditches, rivers, streams and other watersheds whenever banks are sufficiently high, beavers dig burrows. In the plain areas, they build lodges (Figure 4) boring tunnels under the water and arranging chambers above the water level.

Figure 4. Beaver lodge in the mixed spruce-deciduous forest (©Olgirda Belova)

However, from the human attitude, the beaver is considered as a problematic species caused damage to forests and adjacent agricultural lands due to its feeding and building activities (Figure 5).

Figure 5. Forest block and forest road flooded by beaver (©Olgirda Belova)

Beaver building (engineering) activity (building of dams, and digging channels, felling of trees) and flooding of large areas significantly alter the character and appearance of the waterbodies and cause changes in species composition but, simultaneously, improve the living conditions not only of its family but also significantly affects the welfare of other animals and plants. Further, the banks of streams recover to the natural meandering state. Illuminated and warmed shallow water in the water bodies creates fertile conditions for the development of wetland communities.

Beavers reach sexual maturity (i.e. the age when breeding results in the first litter) at 1.5–3 years of age. They reproduce only once per year mating in January-March, coming into oestrus for only 12 to 24 hours with peaking in January. The gestation period is relatively long, on average 105 days; give birth in May-June, a lactation 1.5 months. Beavers have a long maturation period for the young that stay with their parents for two years. Beavers are monogamous and the female is dominant. The family consists of 5-6 individuals as rule including parents that own the territory, 1-2 yearlings (2-4 in the North American beaver) and the kids of the previous year. The movement of two-year-old animals is longest and it occurs during their dispersal from parental areas, most often in spring and summer of their second year. However, they do not move far (near 1 km) from parental territory and can come back if did not find suitable habitats.

The territory of a family group is from 100 – 150 m to 0.5 – 1.5 m along a riverbank or shoreline. The most actively used zone is not more than 20-30 m from the water. Within wetland areas, beavers make shorter (0.5–1 km) annual shifts in areas of use. Beavers appear to expand or contract their home ranges depending on food availability. Their territories are usually permanent. Because beaver families tend to use the most preferred food more rapidly than it can be replenished, they continually make adjustments to the areas they use or move up or down streams or along shorelines to more favourable areas. These movements are usually not large but might be 1–2 km.

References

Dvořák, J. 2013. Diet preference of Eurasian Beaver (Castor Fiber L., 1758) in the environment of Oderské vrchy and its influence on the tree species composition of riverbank stands. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, LXI (6): 1637–1643.

Fauna of Lithuania. 1988. Mammals [Lietuvos fauna. Žinduoliai]. Vilnius, Mokslas, 295 pp.

Belova, O. 2006. Assessment of the beaver importance and influence to the forest ecosystem and recommendations for population management. Sc. Rep. Kaunas-Girionys, 34 pp.

 

 

DATA&MODELS

DATA & MODELS

By the 1900’s beaver population in Eurasia had fallen from 100 million to 1 000 and e.g. in Germany from several hundred thousand to only 200. Today, beaver populations in Europe are recovering rapidly, and there are no major threats (e.g. threats of a magnitude likely to cause decline at the regional level. Due to rapid recover, in 2006 the minimum estimate of beaver population in Europe was 639 000. Only in Lithuania, the minimum number of beavers is estimated at 85 879 individuals, the maximum number amounting to 121 025 individuals at the more than 48 000 registered beaver sites (Belova 2016). Beaver number continues increase in Latvia (100 000 – 150 000 beavers), Estonia (16 300 – 17 500), Finland (1 500 – 2 500), Sweden (130 000), Poland (40 000- 80 000). The partial protection of species, e.g. in Poland (Polish Minister of the Environment 2011) contributed to rapid population growth and further spreading to new areas, including near human settlements (Flis 2013; ClientEarth 2016). Beavers are a keystone species, for where beavers build dams the wetlands spread behind them, providing home and food for dozens of species, from migrating ducks to moose. The rapidly expanding beaver population requires new decisions and models considering its status in Europe and damage to forestry and crops. In some countries, the special regulations on assessment and management of beaver sites were adopted. In Lithuania, on the ground of such assessment, beaver dams are divided into “good” (damage is negligible) and “bad” ones (damage is serious). These dams have to be removed.

References

Belova, O. 2016. Management of Beaver Population in the Baltic Sea Countries – A Review of Current Knowledge, Methods and Development Needs. WAMBAF, Interreg Baltic Sea region, 35 pp.

Flis, M. 2013. Ecological, legal and economic aspects of evaluating the damages caused by wild animals. Environment Protection and Natural Resources 24: 53-58.

ClientEarth. 2016. Beavers among wildlife under threat from Polish legal proposals. Available at: http://www.clientearth.org/beavers-polish-nature-plan-threat/

MANAGEMENT

The historic decline in beaver populations was caused by over-hunting for fur, meat and castoreum (a secretion from the scent glands), combined with loss of wetland habitats. Beavers were reduced severely in most countries by medieval times. Since 19th century, further reduction using also efficient steel traps and accurate firearms, caused a rash of final beaver extinction. These reasons have combined with and drainage of many of the large marshland areas, in which the species clung on (all of the European refuge where the species survived, except in Norway, are extensive marshlands) (IUNC 2016). Moreover, forest logging changes drainage patterns and reduces 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 impacts on beaver populations. Continuing human-induced landscape transformation results in habitat loss, increased isolation between landscape fragments and new disturbance types that challenge population (Belova 2016). However, due to legal protection and targeted conservation measures including hunting 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 BS 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 Sweden, Finland, Latvia, Lithuania and Estonia, which are listed in Annex V of the Directive. In Finland, previously allopatric two beaver species becomes sympatric ones. Competitive exclusion of the native Eurasian beaver C. fiber by the North American C. canadensis may be a threat in parts of Finland but it is not a major threat regionally. North American beavers are now confined entirely to Finland, where populations are increasing only slowly (due to heavy harvesting) (Halley and Rosell 2002; Belova 2016).

Beaver management aims to decrease the level of damage caused to forest due its engineering and foraging activities flooding. This management should be at the watershed scale, except where large human-made dams form significant barriers to spread (Halley and Rosell 2002). The management includes three basic and inseparable points as a) quantitative (number control via hunting) b) qualitative (control of population sex and age structure) and c) territorial (habitat management) management (Belova 2006, 2008, 2013). Beaver hunting should be regulated as the optimal management regime in managed landscapes with healthy beaver populations (Halley and Rosell 2002). The management strategy incorporates both technical assistance and direct control via physical exclusion, habitat management by water level manipulation, and population management through hunting/trapping. Within the EU, traps must meet international standards for species referred to in Agreement on International Humane Trapping Standards (AIHTS). For beaver, allowable are Conibear-type traps.

Protection of roads, dams in the man-made impoundments, ditches and drainages would enhance the protection of human health and safety. Before beginning any beaver control action, the beaver problem should be assessed fairly and objectively whether beavers really causing damage or creating hardship requiring control action. The very presence of beaver is often seen as a problem when, actually, the beavers are causing no harm. If damage is evident, prevention of damage or relocation of animals are insufficient and removal of the dam can solve the problem (Boume 2001; Parker and Rosell 2003; Belova 2012; Campbell et al. 2016). However, removal of beaver dams stimulates their reconstructive (building) activity and animals re-build dams on the average within 24 hours (Belova 2012). Despite these activities, dam removal is widely used helping to protect forest and watersheds.

The recommendations on beaver population management were suggested in Lithuania. Following the common laws of population ecology, if the abundance of the certain unmanaged population under favourable conditions exceeds the carrying capacity and, moreover, overpopulation cause not only a lack of preferred suitable habitats but also spread of contagious0 diseases, agents of those do not typically display. The extensive hunting/trapping 15% annually stabilizes local population; however, an increase in the damage caused to forest requires management that is more intensive (20%) and the share of juveniles should be near 50% of all harvested beavers (Belova 2008). In Lithuania, the number of harvested beavers (hunting/trapping using allowable selective traps) was 19 544 in 2015 and 21 749 in 2014, in Latvia, beaver harvesting is more intensive (24 248 and 31 376, respectively). The similar tendency is observed in Finland (5 300 and 6 700) while in Estonia it has increased (6 557 and 5 572) (Belova 2016). Selective removal of beaver dams (simultaneously cleaning drainage ditches) help to maintain the beaver population and reduce damage caused to forest.

References

Boume, J. 2001. Control of Beaver Damage. Agriculture, Food and Rural Development. Alberta Agriculture, Agdex 681-1.

Belova, O. 2008. Integrated ecologically based forest and wildlife management model and recommendations ensuring protection and managing (2005-2010). LFRI, Sc. Rep. Girionys, 50 pp.

Belova, O. 2013. Assessment of Beaver impact and population control. In: Aleinikovas et al. (Eds.): New Recommendations for Agriculture and Forestry. Akademija, p. 51-54 (in Lithuanian

Halley. D.J. and Rosell, F. 2002. The beaver’s reconquest of Eurasia: status, population development and management of a conservation success. Mammal Review 32(3): 153–178.

Campbell-Palmer, R., Gow, D., Campbell, R., Dickinson, H., Girling, S., Gurnell, J., Halley, D., Jones, S., Lisle, S., Parker, H., Schwab, G. and Rosell, F. 2016. The Eurasian Beaver Handbook: Ecology and Management of Castor fiber. Pelagic Publishing Ltd., UK, 214 pp.

Parker, H. and Rosell, F. 2003. Beaver management in Norway: a model for continental Europe? Lutra 6(2): 223-234.

TRADE

The main products from beaver are its high quality fur, castoreum and meat. Furs of beavers have been the most valued. The density of beaver pelage on the back is 12 000 hairs per 1 cm2, on the belly 23 000/1 cm2 in the growing period and 27 000/1 cm2 in winter (Belova 2006). Prized for their warmth, luxurious texture, and the longevity of fur as a material, furs have played a large role in clothing people since the beginning of human history. Furs have been used for the production of outerwear as coats and cape, garment and shoe lining, a variety of head coverings, and ornamental trim and trappings. Depending on the supply of animals, Russian, Northern Scandinavia, and Central Asia were the major supplies of this trade through the 15thcentury (Wolf 1982). There were substantial populations of the Eurasian Beaver throughout northern Europe and Siberia, until they were severely depleted in the 17th century due to over-hunting. The depletion of Eurasian beaver populations coincided with the establishment of European colonies in North America by the early-to-mid 17th century.

Today the importance of the fur trade has diminished; it is based on pelts produced at fur farms and regulated fur-bearer trapping, but has become controversial. Animal rights organizations oppose the fur trade, citing that animals are brutally killed and sometimes skinned alive.

Since medieval times, the tail of the beaver covers an even more singular feature. Beavers have castor, from the Latin castratum. The beaver’s sexual organs are modestly tucked up inside its body, while a pair of glands in the anal area of both sexes secrete castoreum, the musky oil the beaver uses to grease its coat and mark scent mounds to delineate its territory. Castoreum was a popular medicine in the Middle Ages against ailments ranging from headaches to impotence; it is high in salicylic acid (that is the basic ingredient of aspirin), which the beaver ingests by dining on willow bark. Long used as a base for perfume, its scent is described as a pungent, waxy, burnt-orange odour, with smoky notes of Irish peat fires and good pipe tobacco and undertones of cardamom and tea (Svendsen 1978; Outwater 1996). The archaeological excavations and geomorphological investigations have revealed the presence of beaver bones from 5.50% to 66% of all animals found in different settlements of the Baltic region during the Late Neolithic (Balodis et al. 1999). The recent limited consumption of beaver meat may be partly due to the lack of public knowledge of its nutritional quality. A beaver carcass on average constitutes 48.6% of beaver body mass and contains 62.8% of meat, 14.5% of fat and 22.4% of bones (Jankowska et al. 2005; Razmaitė et al. 2011; Strazdina et al. 2015; Żochowska-Kujawska et al. 2016). Beaver meat is a high quality protein and lysine source due to its well-balanced essential amino acid composition. With predominant polyunsaturated fatty acids and the n-6/n-3 PUFA value of 2.1, it could be n-3 PUFA-rich food in the diets (Razmaitė et al. 2011; Strazdina et al. 2013). Smaller muscle fibres, thicker perimysium, and lower amount of IMF material in comparison with pig muscles characterize beaver meat. It is a good substitute for pork in sausage production (Żochowska-Kujawska et al. 2016). An increase in consumption and sustainable hunting as a management tool for beaver population is highly demanded. It should be considered that the most common diseases found in Castor fiber are different types of infections in the intestinal tract, for example the beaver fluke Paramphistomum castori, parasites and pseudo tuberculosis (Rosell et al. 1996 in Bau 2001) report of high levels of the parasites Stichorchis subtriquetrus and Travassosius rufus – both helminths (Bau 2001) and other ones. Most dangerous is Trichinellosis is a parasitic disease of public health importance caused by the nematode Trichinella spiralis. Human infections occur by consumption of insufficiently cooked infected meat. Fresh meat must fulfil the animal health requirements laid down in the EU legislation applicable to each classification of game animal. Every game production should be under hygiene and veterinary inspection. The principles of risk management of food safety have to be incorporated wherever appropriate in the design and implementation of meat hygiene programmes. Legislation should include provisions for hunters, gamekeepers and managers to note any unusual conditions observed during hunting and, where appropriate, during evisceration of the each game specimen, and to report any anomalies to the veterinary inspectors. Legislation should also contain precise but realistic guidelines and rules for hygiene standards and design of larders and processing premise for game. These actions can ensure that game meat is safe from the point of origin to that of consumption (EEC 1992; FACE 1995; Lecocq 1997).

REFERENCES

European Economic Community (EEC). 1992. Council Directive 92/45/EEC of 16 June 1992 on public health and animal health problems relating to the killing of wild game and the placing on the market of wild-game meat. Official Journal of the European Communities No. L. 268/35 of 14.09.92, 19 pp.

Federation of Field sports Associations of the European Union (FACE). 1995. Handbook of hunting in Europe. FACE, Brussels, 750 pp.

Jankowska, B., Żmijewski, T., Kwiatkowska, A. and Korzeniowski, W. 2005. Composition and properties of beaver (Castor fiber) meat. European Journal of Wildlife Research 51(4):283-286.

Outwater, A. 1996. Nature’s Hydrologists. In: Water: a natural history. Ch. 2 ©Alice Outwater. Available at: http://www.profumo.it/perfume/internet-documents/beaver/beaver_natural_history.htm

Razmaitė, V., Šveistienė, R. and Švirmickas, G.J. 2011. Compositional Characteristics and Nutritional Quality of Eurasian Beaver (Castor fiber) Meat. Czech Journal of Food Science 29(5): 480–486.

Strazdina, V., Jemeljanovs, A., Sterna, V. and Ikauniece, D. 2013. Nutrition Value of Deer, Wild Boar and Beaver Meat Hunted in Latvia. In: 2nd International Conference on Nutrition and Food Sciences IPCBEE vol.53 (2013) © IACSIT Press, Singapore DOI: 10.7763/IPCBEE 53, 14, p. 71-76.

Strazdina, V., Sterna, V., Jemeljanovs, A., Jansons I. and Ikauniece, D. 2015. Investigation of beaver meat obtained in Latvia. Agronomy Research 13(4): 1096–1103.

Svendsen, G.E. 1978. Castor and Anal Glands of the Beaver (Castor canadensis). Journal of Mammalogy 59(3): 618-620.

Wolf, E. 1982. The Fur Trade. In: The People without History. Berkeley, CA: University of California Press, 158 pp.

Żochowska-Kujawska, J., Lachowicz, K., Sobczak, M., Bienkiewicz, G., Tokarczyk, G., Kotowicz, M. and Machcińska. 2016. Compositional Characteristics and Nutritional Quality of European Beaver (Castor fiber L.) Meat and its Utility for Sausage Production. Czech Journal of Food Science 34, 2016 (1): 87–92

COUNTRY SPECIFICS

FINLAND

In Finland, the most important becomes 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, O. 2016. Management of Beaver Population in the Baltic Sea Countries – A Review of Current Knowledge, Methods and Development Needs. Interreg Baltic Sea Region, WAMBAF, 37 pp.

ESTONIA

Belova, O. 2016. Management of Beaver Population in the Baltic Sea Countries – A Review of Current Knowledge, Methods and Development Needs. Interreg Baltic Sea Region, WAMBAF, 37 pp.

Jõgisalu, I. 2013. Kopra pesakondade inventuur ja kontroll-loendus. (Monitoring and control accounting of beaver families). Estonian Environment Agency (KAUR), Department of Wild Game Monitoring. http://www.keskkonnainfo.ee/failid/Kopra_pesakondade_inventuur_kontroll_lopp.pdf

LATVIA

Strazdina, V., Jemeljanovs, A., Sterna, V. and Ikauniece, D. 2013. Nutrition Value of Deer, Wild Boar and Beaver Meat Hunted in Latvia. In: 2nd International Conference on Nutrition and Food Sciences IPCBEE vol.53 (2013) © IACSIT Press, Singapore DOI: 10.7763/IPCBEE 53, 14, p. 71-76.

Strazdina, V., Sterna, V., Jemeljanovs, A., Jansons I. and Ikauniece, D. 2015. Investigation of beaver meat obtained in Latvia. Agronomy Research 13(4): 1096–1103.

http://www.csb.gov.lv/statistikas-temas/metodologija/mezsaimnieciba-37129.html

LITHUANIA

Belova, O. 2006. Assessment of the beaver importance and influence to the forest ecosystem and recommendations for population management. Sc. Rep. Kaunas-Girionys, 34 pp.

Belova, O. 2008. Integrated ecologically based forest and wildlife management model and recommendations ensuring protection and managing (2005-2010). LFRI, Sc. Rep. Girionys, 50 pp.

Belova, O. 2013. Assessment of Beaver impact and population control. In: Aleinikovas et al. (Eds.): New Recommendations for Agriculture and Forestry. Akademija, p. 51-54 (in Lithuanian)

Belova, O. 2016. Management of Beaver Population in the Baltic Sea Countries – A Review of Current Knowledge, Methods and Development Needs. Interreg Baltic Sea Region, WAMBAF, 37 pp.

Fauna of Lithuania. 1988. Mammals [Lietuvos fauna. Žinduoliai]. Vilnius, Mokslas, 295 pp.

Razmaitė, V., Šveistienė, R. and Švirmickas, G.J. 2011. Compositional Characteristics and Nutritional Quality of Eurasian Beaver (Castor fiber) Meat. Czech Journal of Food Science 29(5): 480–486.

POLAND

ClientEarth. 2016. Beavers among wildlife under threat from Polish legal proposals. Available at: http://www.clientearth.org/beavers-polish-nature-plan-threat/

Jankowska, B., Żmijewski, T., Kwiatkowska, A. and Korzeniowski, W. 2005. Composition and properties of beaver (Castor fiber) meat. European Journal of Wildlife Research 51(4):283-286.

Żochowska-Kujawska, J., Lachowicz, K., Sobczak, M., Bienkiewicz, G., Tokarczyk, G., Kotowicz, M. and Machcińska. 2016. Compositional Characteristics and Nutritional Quality of European Beaver (Castor fiber L.) Meat and its Utility for Sausage Production. Czech Journal of Food Science 34, 2016 (1): 87–92

Zurowski, W. and Kasperczyk, B. 1986. Characteristics of a European beaver population in the Suwalki Lakeland. Acta Theriologica 31(24): 311-325.

SWEDEN-NORWAY:

Halley D.J. and RoseIl, F. 2003. Population and distribution of European beavers (Castor fiber). Lutra 46 (2): 91-101.

Halley, D.J., Rossel, F and Saveljev, A.P. 2012. Population and Distribution of Eurasian Beaver. Baltic Forestry 18(1): 168-175.

Parker, H. and Rosell, F. 2003. Beaver management in Norway: a model for continental Europe? Lutra 6(2): 223-234.

 



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