Ondatra zibethicus - NOBANIS

NOBANIS –Invasive Alien Species Fact Sheet 

Ondatra zibethicus 

Author of this fact sheet: 

Christina Birnbaum, Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, 

Kreutzwaldi 64, 51014 Tartu, chbirnbaum@yahoo.com 

Bibliographical reference – how to cite this fact sheet: 

Birnbaum, C. (2006): NOBANIS – Invasive Alien Species Fact Sheet – Ondatra zibethicus. – From: Online Database 

of the North European and Baltic Network on Invasive Alien Species – NOBANIS www.nobanis.org, Date of access 

x/x/200x. 

Species description 

Scientific names: Ondatra zibethicus, (L., 1766) Cricetidae (Muridae, Arvicolinae) 

Synonyms: Ondatra zibethica, Castor zibethicus, Fiber zibethicus, Myocastor zibethicus, Mus 

zibethicus, Mussascus 

Common names: Muskrat (Musquash) (GB), Swamp rabbit (GB), Marsh rabbit (GB), Marsh hare 

(GB), Bisam (DE), Bisamratte (DE), Moschusratte (DE), Zwergbiber (DE), Zibethratte (DE), 

Bisambiber (DE), Biberratte (DE), Sumpfkaninchen (DE), Sumpfhase (DE), Muschmaus (DE), 

Zibetmaus (DE), Wasserratte (DE), Bisamrotte (DK), Ondatra (EE), Piisamrott (EE), Piisami (FI), 

Moskusrotta (IS), Ondatra (LT), Ondatra / bizamžurka (LV), Piżmak (PL), Ондáтра (RU). 

Fig. 1. Ondatra zibethicus, photo by Nanna Ramsgaard.

Fig. 2 and 3. Close-up of tail and hind feet of Ondatra zibethicus, photo by Nanna Ramsgaard 

Species identification 

O. zibethicus can attain a head and body length of 40 cm, a tail length of up to 25 cm, and a 

maximum weight of 1.5 or 2 kg. The species is especially adapted to an aquatic mode of life: its tail 

is naked and laterally flattened, the nose and ears are closeable, and the edges of its hind feet carry 

swimming bristles (Burghause 1988). It has a “rat-like” appearance but is actually closely related to 

voles Microtus spp. and lemmings Lemmus spp (Banfield 1974). 

Native range 

O. zibethicus originates from North America. 

Alien distribution 

The central European populations of O. zibethicus are recruited from at least two centers of 

dispersal. Two males and three females were released for hunting purposes at Dobrisch near Prague 

around 1905 (cf. Hoffman 1958). In 1908 it was introduced to the Czech Republic for fur farming. 

Some animals were said to have been kept at Krumau on the upper Moldavia River at about the 

same time (possibly since 1888), and another group of O. zibethicus was supposedly released at 

Tabor in 1905 (according to Hoffman 1958). Within a few years, these private stocks probably gave 

rise to a wild population in Bohemia, which gradually extended its range, invading Bavaria in 1914, 

and Saxony and Silesia in 1917. From their Bohemian center, O. zibethicus spread across the 

Sudeten Mountains into the Oder Basin, across the Lausitz Mountains to the Spree River, over the 

Fichtelgebirge to the rivers Saale and Main, and over the Bohemian Forest to the Naab and Danube. 

They spread rapidly along the Elbe River, attaining its mouth in 1947 (the first specimens were 

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found in Hamburg in 1933; i.e. after having covered a straight distance of 550 km in only 28 years; 

their colonization of the Elbe and Havel rivers is described by Hoffmann 1958). O. zibethicus 

subsequently colonized eastern Germany, spreading westward across the Mecklenburg lake district 

(Kintzel 1985; cf. Kirchner 1954). In western Germany, Schröpfer & Engstfeld (1983) state that 

they have inhabited the entire Emsland, for instance, since 1967. 

In southwestern Germany, O. zibethicus invaded the counties of Kehl, Offenburg and Lahr in 1932, 

and the counties of Lörrach, Freiburg, Emmendingen, Müllheim, and Säckingen in 1955. By 1980, 

it had colonized every county in the State of Baden-Württemberg. O. zibethicus is now naturalized 

throughout all of Germany (Heidecke & Seide 1986). 

For financial reasons, Finland imported about 1, 100 O. zibethicus from Germany, Czechoslovakia 

and North America (Artimo 1960). The animals were released in a total of 293 localities all over 

Finland from 1919 and onwards. Within 35 years (1920-1955) O. zibethicus had established in 

almost all available habitats, with the exception of those in the northernmost parts of Finland. In 

northern Finland, the spread has been distinctly slower than in southern Finland. The spread has 

varied within limits of 4-120 km per year, but usually O. zibethicus has spread at rate of 10-20 km 

per year. 

From northern Finland O. zibethicus spread into Sweden, and in 1957 the species had fully 

occupied the lower region of the border river Torneälven (Artimo 1960). In Sweden, there have 

been and still are excellent possibilities of studying the dispersal rate of the O. zibethicus 

southwards in the country (Danell 1996). 

In 1927, 10 O. zibethicus were introduced from Finland to Russia. Twenty individuals from Finland 

were released to the wild (nature) near the islands of Solovets. Beginning in 1928, O. zibethicus was 

released in massive numbers in the territory of the Soviet Union. By 1955 large areas near different 

water bodies were occupied by about 160,000 O. zibethicus (Lavrov 1957). 

In the early 1930s O. zibethicus was also introduced to the Kola Peninsula (Lund and Wikan 1995). 

In total, about 1,000 O. zibethicus were released on the Kola Peninsula during 1931-1936. Just 

before 1950 O. zibethicus occurred all over the peninsula (Semjonov-Tian-Sjanskij 1987). 

1650 O. zibethicus were imported into Russia in 1928 - 1932 from Finland, Canada and England. 

After that ten thousand animals caught in new settlements, were released in the nature. Natural 

moving happened very quickly too and by 1970 the muskrat has occupied almost all suitable 

territories. Their distribution in Russia is from the western border up to Kamchatka. It exceeds the 

natural area significantly. 

Between 1980 and 1988 there are very few observations of O. zibethicus in Norway. Since 1988 

there has been a rapid population increase in Sör-Varanger, and today O. zibethicus has spread to 

almost every part of the municipality (Danell 1996). Little is known about the distribution and 

abundance of O. zibethicus in other parts of Finnmark or the rest of Norway, but it seems likely that 

the species has a scattered distribution and low population numbers (Lund 1995). O. zibethicus has, 

however, been documented shot or caught in gillnets intended for fishing, in Hattfjelldal in 

Nordland county and in Lierne in North Trøndelag county in 2005. For both areas it appears that O. 

zibethicus has migrated into Norway along watersheds crossing the mountain range along the 

border. South of the mountainous areas the O. zibethicus probably will spread easier across the 

border and also spread north-south on rivers in southern Norway. 

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The incidental record of O. zibethicus in Denmark was from the island of Rømø in 1989 

(Ramsgaard and Christensen 2006). Since 2000, O. zibethicus has been regularly reported from the 

southern parts of Denmark close to the German borders, the size of the population has, however, not 

been determined yet (Ramsgaard 2005, Ramsgaard and Christensen 2006). 

In France, O. zibethicus farms were founded in the southern Vosges Mountains after World War I. 

When the price of O. zibethicus furs plunged during the 1920s, a number of farms closed and 

released their animals (e.g. 500 animals in 1928 near Belfort). This population spread to 

Switzerland and Alsace by 1930, and the Meuse and Moselle rivers in 1935. 

O. zibethicus was introduced twice to Estonia: in 1947, 190 animals and in 1952, 361 animals, 

raised from the original stock, were released to water bodies in southern and western parts of 

Estonia (N. Laanetu, pers.comm.). 

The first record of O. zibethicus in Latvia is from 1961; it spread from Belarus and later also from 

Estonia and Lithuania, where it was introduced (Ozols 1997). 

Pathways of introduction 

O. zibethicus was introduced for fur farming and breeding purposes. 

Alien status in region 

O. zibethicus is present in most of the countries of the region (see table 1). In some parts of Estonia 

the American mink (Mustela vison) has displaced O. zibethicus by taking its habitat (Kukk 2001). 

However, in other parts of Estonia O. zibethicus is still present, e.g. in South-Estonia and near the 

Narva reservoir (in north-east of Estonia) (Kull et al. 2005). 

O. zibethicus occurs throughout Poland. However, within the last 15 years, the numbers have 

dropped significantly (by 81% in NW Poland). This is partly due to the presence of Mustela vison, 

since Mustela vison occurs only in the northern part of the country and the decrease in O. zibethicus 

was recorded in all of Poland (Polish Alien Species Database). 

In Norway O. zibethicus occur in areas with quite unfavourable habitats where population density is 

very low (Danell 1996). 

The status of O. zibethicus in Latvia is not known; but in later years the number of O. zibethicus has 

decreased, because of its natural enemies, such as Mustela vison and Arvicola terrestris (Ozols 

1997, J. Ozoliņš, pers. comm.). 

In Russia O. zibethicus kept its new huge area, but its quantity has significantly decreased for the 

last 15 - 20 years. There are many reasons for the quantity decline, but in the north of the area there 

has been a reduction of edible plants and intensive growth of inedible plants (Павлов, и др.1973, 

Соколов, Лавров, 1993.) 

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Country Not Not Rare Local Common Very Not 

found established 

common known 

Denmark X 

Estonia X 

European part of Russia X 

Finland X 

Faroe Islands X 

Germany X 

Greenland X 

Iceland X 

Latvia X 

Lithuania X 

Norway X 

Poland X 

Sweden X 

Table 1. The frequency and establishment of Ondatra zibethicus, please refer also to the 

information provided for this species at www.nobanis.org/search.asp. Legend for this table: Not 

found –The species is not found in the country; Not established - The species has not formed selfreproducing 

populations (but is found as a casual or incidental species); Rare - Few sites where it is 

found in the country; Local - Locally abundant, many individuals in some areas of the country; 

Common - Many sites in the country; Very common - Many sites and many individuals; Not 

known – No information was available. 

Ecology 

Habitat description 

The animals live semi-aquatically. They are crepuscular, spending the day in burrows or floating 

reed lodges up to 1.5 m in height (mostly during winter – depending on habitat and climate) 

(Heidecke & Seide 1986, Ramsgaard 2005). 

Reproduction and life cycle 

Females usually throw 3 or 4 times per year from late April on, producing 2 to 12 offspring (4 to 7 

on average) annually. In colder climates females may throw only twice a year (Ramsgaard 2005). 

The young grow a nest coat after 18 days, an adolescent coat after about 4 weeks, and the adult coat 

at about 4 months (Burghause 1988). The rate of reproduction depends on food supply, population 

density, and water temperature. The mortality of the offspring increases at low water temperatures 

and high population densities (cf. Meinert & Diemer 1977). Females may attain sexual maturity at 

the age of five months, and the males after seven months (Heidecke & Seide 1986). 

Dispersal and spread 

The principal migration period of O. zibethicus is during spring (peaking in March) and fall 

(peaking in October). The migration period may extend from fall to spring during very mild 

winters. The rate of dispersal varies from year to year, depending mostly on the survival rate of the 

litter in spring, as well as on the amount of precipitation during the summer, as low water levels 

strongly impede the dispersal of the species (Burghause 1996). Dispersal rates of 6-8 km/year have 

been reported from several countries in Europe including Denmark (Ramsgaard and Christensen 

2006 and references therein). High water levels may provide stochastic dispersal opportunities 

(Ramsgaard 2005). For example O. zibethicus can migrate long distances (up to 160 km/day) by 

rafting, being carried long distances by river currents (Böhmer et al 2001) 

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Impact 

Affected habitats and indigenous organisms 

O. zibethicus feeds mainly on the plants of reed belt communities (Pietsch 1982; Krauss 1990; 

Diemer 1996), particularly on common reed (Phragmites communis). According to Burghause 

(1988), one animal is capable of cropping 1.5 m 2 per night. O. zibethicus also likes to dig for roots, 

and it is particularly attracted to the tubers of Jerusalem artichoke (Helianthus tuberosus), a 

common neophyte in river plains (Burghause 1988, 1996). O. zibethicus is a generalist but usually 

only eats a few species, which for example could be the plant species mentioned above (Ramsgaard 

2005). Small well-vegetated lakes with relatively stable water levels are especially favored by O. 

zibethicus in Finnish waters, but heavy impacts have also been reported in waters with poor stands 

of helophytes (Rintanen 1976). O. zibethicus grazing affects the structure of littoral vegetation 

(Danell 1977, 1979). This change in vegetation affects communities of aquatic invertebrates 

(Nummi et al. 2005). 

O. zibethicus may sometime feed on crayfish, zebra mussels, crustaceans, and insects (cf. Ulbrich 

1928, Hoffmann 1958), bivalves - including threatened taxa such as Anodonta, Unio, and the 

freshwater pearl mussel Margaritifera margaritifera (cf. Brander 1955; Baumann & Everding 1986; 

Hochwald 1990; Zimmermann et al. 2000). This indirectly affects rare fish species that deposit their 

eggs in bivalves, such as the bitterling (Rhodeus amarus). 

The effects of spreading of O. zibethicus are often linked with those of anthropogenic pollution, as 

in the case of the decline of reed belts in many lakes (Kintzel 1985; Barthelmes 1991). According to 

Barthelmes (1991), long-term observations at a lake in Berlin (Grosser Müggelsee) have shown that 

the decline in reed cover may have been due mainly to the feeding pressure exerted by O. 

zibethicus. In Kintzel (1985), Stüber reports that at the Lake of Döbbertin "the plant cover was 

usually destroyed completely after one or two years, after which O. zibethicus moved on". 

Bernhardt and Schröpfer (1992) have shown that in the Ems region O. zibethicus removes bulrushes 

(Typha latifolia), promoting the development of club-rushes (Schoenoplectus lacustris). 

All in all, the general opinion on the impact of O. zibethicus on their habitat is mixed, especially in 

northern Europe. On one hand, the animal is regarded as a positive factor because it creates 

openings in dense vegetation stands and it prevents lakes from being overgrown by vegetation. On 

the other, it has been blamed for destroying valuable vegetation and creating mud-flats. Depending 

on human interest in the development of the particular wetland, O. zibethicus may be regarded as a 

valuable element or as a “pest” species (Danell 1996). 

The American mink (Mustela vison), which is now spreading throughout Germany, is an important 

predator of O. zibethicus (Burghause 1988; Stubbe 1993). Other natural enemies are martens, 

European polecats, weasels, foxes, lynxes and various birds of prey and large owls; however, the 

populations of these predators have been anthropogenically decimated, so that their predation 

pressure on O. zibethicus is low. (O. zibethicus is difficult to catch for most of the predators since it 

spends most of its time in the water. The O. zibethicus taken by the mentioned predators are often 

sick or young animals which spend more time on land (Ramsgaard 2005). 

Genetic effects 

No known genetic effects. 

Human health effects 

According to Hoffmann (1958), O. zibethicus is host to a great number of parasites (41 species of 

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trematodes, 22 species of cestodes, 27 species of nematodes, and others), notably various species 

capable of infesting humans, such as the dog tapeworm (Taenia hydatigena), the cat tapeworm 

(Taenia taeniaformis), and the dwarf tapeworm (Echinococcus multilocuralis; cf. Diemer 1996). 

O. zibethicus only occasionally affect humans directly. This occurs in situations when the animals 

are cornered. They defend themselves vigorously and may even attack humans (Danell 1996). 

Economic and societal effects (positive/negative) 

O. zibethicus may dig far into the banks of water bodies. Their extended burrowing activity can 

cause serious economic damage (undermining of banks, dams, road and railway embankments) 

causing their collapse during floods. Also damage to flood protection structures (destabilization of 

flood dikes), and to fish farms (chewing through nets and fish traps) have been observed 

(Burghause 1996). The system of passages of one O. zibethicus family may extend up to 25 m along 

the bank and 15 m inland. In Germany the costs of economical impacts caused by O. zibethicus are 

regarded to be 12,400,000 euros (Reinhardt et al 2003). 

O. zibethicus may also reduce the ecological value of wetlands of interest to nature conservation 

destroying the reed belts, feed on endangered plant species and prey upon rare freshwater bivalves. 

The animal moves four times its own weight in gnawed off plants. About a quarter of this is eaten 

by the animal, creating quite a lot of dung which usually goes into the water. 

In Sweden O. zibethicus is called a “keystone” species because it creates better living areas for 

water fowls and insect as it creates openings in dense vegetation stands and thus prevents lakes 

from being overgrown by vegetation (Danell 1996). 

Management approaches 

Prevention methods 

Indications that the spreading of O. zibethicus would result in serious damages already existed at the 

beginning of the 20th century. The first police regulations in Germany on O. zibethicus control were 

enacted in Saxony and Bavaria in 1917, and provided the basis for the organization of the first 

control institutions after World War I (Hoffmann 1958, Burghause 1996). The increasing problems 

caused by O. zibethicus in Germany led to the creation of a State Control Service (Reichsbekämpfungsdienst) 

in 1933. The State Regulation on O. zibethicus Control (Reichsverordnung zur 

Bekämpfung der Bisamratte) came into effect on July 1 st 1938, based on the Act for the Protection 

of Cultivated Plants (Gesetz zum Schutze der Kulturpflanzen) of 5 May 1937. 

The Bern Convention on the Preservation of European Wild Plants and Animals and their Natural 

Habitats lists O. zibethicus in Recommendation No. 77 among those species which demonstrably 

pose a threat to biological diversity, and therefore recommends its extermination. However, 

Burghause (pers. comm.) asserts that it has been obvious for decades that an extermination of O. 

zibethicus is no longer possible, not even at considerable effort. 

According to Estonian List of Invasive Alien Species (Ordinance of the Minister of Environment, 

no 126 of 7th Oct. 2004) it is forbidden to bring O. zibethicus in the country for artificial breeding 

or keeping. In the Nature Conservation Law in §49 and §57. cases are described where particular 

prevention actions should take place (considering the problems of (invasive) species and their 

massive distribution. 

Eradication, control and monitoring efforts 

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The choice of the control method depends on the specific features of the problem and the 

characteristics of the impacted area. 

In some countries the control of O. zibethicus is no longer focused on the extermination of the 

species, which is judged impossible. Instead, it is targeted at slowing down the rate of spreading and 

at controlling the population size in critical situations. By these measures, Rhineland-Palatinate has 

succeeded in preventing serious O. zibethicus damage, according to Burghause (1996). However, 

statewide control in Germany of O. zibethicus was only regarded as a reasonable task as long as 

there was hope of keeping certain areas pest-free (Burghause, pers. comm.). 

Direct control of O. zibethicus in Germany, for example, has been conducted with traps (cf. Bothe 

1993), poisoned bait (chlorphacinon), ferrets, poison gas, and firearms (Burghause 1996). 

In the Netherlands O. zibethicus are caught in underwater traps constructed to make entry easy but 

exit difficult. The animals drown using this method, but this is accepted in the Netherlands as the 

period between when O. zibethicus realizing there is no way out and it is drowned within the 

internationally accepted time limit. In the Netherlands during the last decade of last century the 

number of catches was about 30,000 animals and in 2002, 363.042 O. zibethicus were caught 

(Landelijk Jaarverslag 2002). 

In Sweden, trapping of O. zibethicus has been insignificant due to the low price of O. zibethicus furs 

and the banning of leghold traps. Furthermore, the species has not been regarded as a “pest” animal 

in Sweden and therefore there have been no campaigns to reduce their numbers (Danell 1996). 

In Estonia O. zibethicus is a hunting object, which can be also considered as a controlling method. 

According to the Hunting Law in Poland, O. zibethicus occurring in fish ponds can be shot 

throughout the year. Outside fish ponds, the species can be hunted between 11.04 and 15.04 (Polish 

Alien Species Database). In Latvia, according to Hunting Law, O. zibethicus can be shot from 

October 1 st – March 31 st and in unlimited numbers. In the open season of year 2004/2005, 69 O. 

zibethicus were caught in Latvia. 

According to Burghause (1996), the "most successful, but also the most expensive" form of O. 

zibethicus indirect control is fortification of the embankments. The banks of water bodies are 

protected against O. zibethicus essentially by inserting a layer of plastic foil. These sections are 

additionally reinforced with a strong layer of large stones. 

Information and awareness 

In Estonia two booklets introducing invasive species of local importance have been published 

(Kukk et al 2001, Kull et al. 2005.). The purpose of those booklets is to make the wider range of 

people aware of the problems going hand-in-hand with the spread of invasive species. The booklet 

also aims to show how the species look and to explain how the spread of species could be 

controlled. 

Knowledge and research 

In Denmark registration of the O. zibethicus distribution has taken place with the use of O. 

zibethicus rafts (Ramsgaard 2005, Ramsgaard and Christensen 2006). In Norway, there are no 

recent mappings of the O. zibethicus distribution and no analyses of the dispersal rate during 

different periods (Danell 1996). 

Recommendations or comments from experts and local communities 

A monitoring program for O. zibethicus is recommended. It should focus on the maximum population 

density attained in the absence of control measures, and on the efficacy of predation by mink 

(Mustela vison). Lauenstein (pers. comm.) expects that some government agencies may reassess 

their position in the next few years, because the widespread lack of control activities could result in 

8

a serious aggravation of the O. zibethicus problem. Furthermore a better co-operation between the 

implicated countries is needed to collect better knowledge of the species (Nanna R. Ramsgaard, 

pers. comm.). 

References and other resources 

Contact persons 

Nikolai Laanetu (EE) Centre of Forest Protection and Silviculture, Iva 12, 12618 Tallinn, Tel: +372 

6 771 301, Fax: +372 6 771 300, E-mail: nlaanetu@hotmail.com 

Frank Klingenstein (DE) Bundesamt für Naturschutz (Federal Agency for Nature Conservation) 

Konstantinstraße 110 53179 Bonn -- www.bfn.de Tel.: ++49(0)228/8491-264, Fax: -119, E-mail: 

frank.klingenstein@bfn.de 

Pall Hersteinsson (IS) PhD, Professor of Mammalogy, Institute of Biology, University of Iceland, 

Sturlugata 7, IS-101 Reykjavik, Iceland, Tel.: +354-535 4608, E-mail: pher@hi.is 

Petri Nummi (FI) Lecturer in wildlife ecology and management, Department of applied biology 

FIN-00014, University of Helsinki, Tel: +358 9 191 58366, E-mail: petri.nummi@helsinki.fi 

Wojciech Solarz (PL) Institute of Nature Conservation, Polish Academy of Sciences Mickiewicza 

33, 31-120 Krakow, Poland, Tel. +48 609 440 104 E-mail: solarz@iop.krakow.pl 

Thomas Secher Jensen (DK) Aarhus Universitet, Naturhistorisk Museum, Universitetsparken, 

Bygning 210, DK-8000 århus C, Tel:. +45 86 12 97 77, E-mail: 

Thomas.Secher.Jensen@nathist.au.dk 

Nanna R. Ramsgaard (DK) Tordenskjoldsgade 29 st th. 8200 Århus N Tel.: Tel. 87390069, E-mail: 

bisam@somewhere.dk 

Steinar Wikan (NO) Svanhovd Environmental Centr, N-9925 Svanvik, Tel. (+47) 78 97 36 00, Email: 

svanhovd@svanhovd.no 

Jānis Ozoliņš (LV) State forest service, Department of hunting, Rīga, 13 janvāra Str. – 15, LV- 

1932, Tel: +371 7212776, E-mail: janis.ozolins@vmd.gov.lv 

Kjell Danell (SE) Swedish University of Agricultural Sciences, Department of Animal Ecology, 

Tel: +46 70 3747974, E-mail: Kjell.Danell@szooek.slu.se 

Johan Danielsen (NO) Directorate for Nature Management, Tungasletta 2, N-7485 Trondheim, 

Norway, Tel.: + 47 73580 949, E-mail: Johan.Danielsen@dirnat.no 

Andrey Warshavsky (RU) Severtsov Institute of Ecology and Evolution, Russian Academy of 

Sciences, Moskow, Leninskij pros., 33, Russia. Tel.:495 1247932. E-mail: Warsh@yandex.ru 

Links 

A review of European mink (Mustela lutreola) 

Polish Alien Species database 

Bisamrotte – Registreringer i Pasvik Naturreservat 1994-2000 

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References 

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438 pp. 

Barthelmes, D. 1991. Schwere Fraßschäden durch Bisamratten (Ondatra zibethica L.) als Ursache für den 

Gelegerückgang in mitteleuropäischen Seen. – Arch. Natursch. Landschaftsforsch. 31(1): 3-18. 

Baumann, A. and R. Everding .1986. Schädling in Naturschutzgebieten. – Der Bisamjäger 21: 9. 

Bernhardt, K. G., Schröpfer, R.1992. Einfluß des Bisams auf die Vegetation - Untersuchungen im Ersatzbiotop Geeste 

im Emsland. Naturschutz und Landschafts-planung 1/92: 20-26 

Bothe, C. 1993. Über die Wirksamkeit, Zuverlässigkeit, Norwendigkeit und Tierschutzgerechtigkeit von Bisamfallen 

und Fangmethoden. Unveröff. Diplomarbeit, Braunschweig. 

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Burghause, F. 1988. Der Bisam – vom Pelztier zum Schädling. – In: Naturhistorisches Museum Mainz (ed.), 

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126pp. 

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Heidecke, D. and Seide, P. ca. 1986. Bisamratte Ondatra zibethicus (L.). In: Buch der Hege, 640-666. 

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Bedeutung. – Leipzig 1958. 

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2(9): 277-281. 

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Date of creation/modification of this species fact sheet: 05-02-2008 

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