|Scientific Name:||Gulo gulo|
|Species Authority:||(Linnaeus, 1758)|
|Taxonomic Notes:||Some authors (Hall 1981) have regarded the North American Wolverine as a species (Gulo luscus) distinct from the Eurasian Wolverine (Gulo gulo). Most recent accounts (Jones et al. 1992, Pasitschniak-Arts and Lariviere 1995, Wozencraft 1993, 2005) treat G. luscus as a subspecies of G. gulo, following Degerbol (1935) and Kurten and Rausch (1959).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Abramov, A., Belant, J. & Wozencraft, C.|
|Reviewer/s:||Duckworth , J.W. & Schipper, J.|
This species is listed as Least Concerned due to its wide distribution and remaining large populations. Wolverine occurs at low density and many Wolverine populations appear to be relatively small and isolated (Ruggiero et al. 2007) and there is evidence of resurgence in some places of its historical distribution (Rowland et al. 2003). Thus although there is an overall continued decline due to human persecution and land-use change, the global decline of this species is not at a rate sufficient to qualify for listing at this time. However, the European Mammal Assessment determined that the European Wolverine is currently Vulnerable (A2c), thus the Least Concern listing is driven by the estimation that some large populations remain in North Asia and North America. Wolverines still face some threats such as over-exploitation through hunting and trapping, predator poisoning programs and habitat resource extraction that caused the contraction of wolverines' historical range. More data on population trends, especially in North Asia, may result in this species being re-assessed as Vulnerable in the near future.
|Range Description:||The species has a circumpolar distribution, corresponding with the Boreal zone of the northern hemisphere (Kvam et al. 1988). The range of the wolverine reaches from Scandinavia through the Russian Federation and Siberia to Alaska, Canada and the western lower states of the United States south to California. The range includes territory of the following countries: Canada, China (Heilongiang, Xinjiang, Inner Mongolia), Estonia, Finland, Mongolia, Norway, Russian Federation, Sweden, and United States (Alaska, Wyoming, Idaho, Montana, Washington, Oregon and California) (Whitman 1999).
During the 19th century, wolverines disappeared from the southernmost of these areas in Europe mainly due to persecution, but also due to deforestation and other human developments. In Europe the species is now found in Norway, Sweden, Finland and European part of Russia. Within these countries wolverines are mainly found north of 60ºN. Based on geographic connectivity and genetic surveys the wolverines in Europe likely consist of five populations/occurrences.
Native:Canada; China; Estonia; Finland; Mongolia; Norway; Russian Federation; Sweden; United States
|Range Map:||Click here to open the map viewer and explore range.|
North America: The distribution and abundance of the species has been notably reduced in the 20th century in United States (Pasitschniak-Arts and Larivière 1995) and during the 19th century, wolverines disappeared from the southernmost of its European distribution mainly due to persecution, but also due to deforestation and other human developments. However, although there has been substantial range reduction, there is evidence of resurgence in some places of his historical distribution (Rowland et al. 2003). Throughout their range, wolverines occur at relatively low densities and require large home ranges varying from at least 100 km² to upwards of 600 km² (Whitman 1999). In Europe, the species is relatively rare. Densities of this species are never high, and it has been found to be less abundant than wolves, even in optimal habitats (Pasitschniak-Arts and Lariviere 1995). Densities range from one per 500 km² in Scandinavia to one per 65 km² in Montana, USA (Pasitschniak-Arts and Lariviere 1995).
Substantial populations occur in northern Canada and Alaska. Outside of Alaska, the population in Montana is considered to be the largest and most stable population of wolverines, given its close proximity to healthy populations in Canada (Cegelski et al. 2003). Densities of wolverines are never high (Aubry et al. 2007, Makridin 1964). Many wolverine populations appear to be relatively small and isolated (Ruggiero et al. 2007).
In North America, population density estimates range from one wolverine per 65 km2 in Montana (Hornocker and Hash 1981) to one per 200 km2 in northern British Columbia (Quick 1953), Alaska (Becker and Gardner 1992), and the Northwest Territories (Lee and Niptanatiak 1993). Lofroth and Krebs (2007) estimated densities for wolverines in British Columbia using existing wolverine distribution, wolverine food, ecosystem mapping and human development data. Density estimates range from 6.2 wolverines/1,000 km2 in high-quality habitat to 0.3/1,000 km2 in rare-quality habitat. Their predicted population estimate for British Columbia was 3,530 wolverines.
Europe: The European population of Gulo gulo is currently estimated to be approximately 2,260 individuals: 1,400 in European Russia (Novikov 2005), 150 in Finland, and 1998–2000 were 326 (±45) individuals in Sweden and 269 (±32) individuals in Norway (Sæther et al. 2005). The southern Norwegian population was naturally re-established during the late 1970s and was a result of protective legalisation (Landa and Skogland 1995). To the east, the Eastern Russian wolverine population is believed to comprise more than 18,000 individuals (Novikov, 2005). The species is not abundant in Mongolia, but still relatively widespread: it is only found in northern taiga habitats in Hentii and Hövsgöl mountain ranges (Bannikov 1954, Dulamsteren 1970), northern parts of Hangai Mountain Range and Mongol Altai Mountain Range (Dulamtseren et al. 1989).The European distribution is connected to the East Russian population along the Urals. The overall European population forms a relatively continuous distribution with a few geographically and genetically distinct subpopulations and constitutes a smaller fraction of the large Eurasian population.
1. Scandinavian wolverine population: The Scandinavian wolverine has shown a low genetic variability and subdivision among populations indicating that the wolverine in Scandinavia has lost variation due to a previous bottleneck event and that the current populations are the result of a recent common genetic background (Walker et al. 2001, Flagstad et al. 2004). The current population estimate is 580 individuals (>1 yrs of age) with approximately 200 in Norway and 380 in Sweden (Larsson 2005, van Dijk et al. 2005). The population has a continuous distribution and is narrowly connected to the Finnish – Western Russian population along the border of Finnmark County in the northernmost parts of its distribution. However, an initial genetic analysis has indicated a clear genetic distinction between these populations (Ø. Flagststad pers. comm.). In its southern distribution, the Scandinavian wolverine population provides as a source for the Southern Norwegian wolverine population (Walker et al. 2001, Flagstad et al. 2004, Flagstad et al. 2006) as well as a source for the Swedish forest wolverine population(s) close to the Gulf of Bothnia in Southern Sweden (Hedmark 2006).
2. Southern Norwegian wolverine population: The southern Norwegian population was naturally reestablished during the late 1970s and was a result of protective legalisation (Landa and Skogland 1995). This population has recently increased in numbers and distribution, but is currently kept at around 100 individuals by various control measurements (Flagstad et al. 2006). Genetic surveys have shown that the Southern Norwegian wolverine population is genetically distinct from the Scandinavian population, but the geographic gap between the southern and the main Scandinavian population to the north and east has decreased from 100-200 km by the early 1990s to virtually connectivity by 2006. However, exchange of individuals still is limited and the Southern Norwegian population seems to form a sink with a few individuals emigrating from the northern continuous population (Landa et al. 2000, Flagstad 2006).
3. Swedish forest wolverine population/occurrence: The Swedish forest wolverine occurrences were naturally established, during the mid 1990s (Hedmark 2006). These new occurrences were likely established by as few as 2 and 2-4 individuals and are currently consisting of 2 and 10 individuals, respectively (Hedmark 2006). Non-invasive genetic surveys has showed that these occurrences have little, if any, contact with the main Scandinavian wolverine population (Hedmark 2006).
4. Finnish – western Russian wolverine population: During the last decades, there has been an increase in population numbers and distribution of wolverines in Finland, but decreasing trends in Russia (Landa et al. 2000a). The western Russian population is estimated to be approximately 1,400 individuals (Novikov 2005). Relationships with other populations: to the west the distribution of the Finnish – Western Russian wolverine population is narrowly connected to the Scandinavian population along common borders with Norway and Sweden. An initial genetic analysis has indicated a clear genetic distinction between the Scandinavian population and the wolverines living in northern parts of Finland (Ø. Flagststad pers. comm.). It is also unclear how the western part of the wolverine distribution within this population (Finland, Kola, Karelia) connects along the narrow isthmus between the White Sea and Lake Onega in Western Russia. This area is judged as an extremely important connection for the northern element of the taiga fauna (Lindén et al. 2000) and these concerns should be further investigated. To the east, the European Russian wolverine population has a wide connection to the much larger East Russian population adjoining along the Urals in western Siberia. The Eastern Russian wolverine population is believed to comprise more than 18,000 individuals (Novikov 2005).
5. Finnish western wolverine population: This population was established by translocating animals from domestic reindeer herding areas in the north during the 1980s-1990s. The population is estimated to consist of about 10-15 individuals and now seems to reproduce naturally (Kojola 2005). The gap between this and the Karelia distribution is about 200-300 km and little is known about exchange between these populations. This population/occurrence should therefore be judged as isolated from other populations until further knowledge is gained.
|Habitat and Ecology:||
Wolverines inhabit a variety of habitats in the alpine, tundra, taiga, and boreal forest zones. They are found in coniferous, mixed, and deciduous woodlands, bogs, and open mountain as well as tundra habitats (Mitchell-Jones et al. 1999). Snow is generally regarded as an important component of the wolverine's seasonal habitat requirements (Banci 1987, Hatler 1989). Wolverine habitat selection is negatively affected by human activity, including roads, infrastructure, and backcountry recreation (May et al. 2006; Krebs et al. 2007). The wolverine has vast home-ranges (Landa et al. 1998), vary from 100 to 500 km2 for males and 100 to 200 km2 for female, and good dispersal abilities. Faecal DNA sampling has detected dispersal distances of more than 500 kilometres (Flagstad 2005, Flagstad et al. 2006). Hornocker et al. (1983) consider this species as solitary, which influences the large home ranges and extensive seasonal movements.This species is nocturnal with some daylight activity and it is considered as opportunistic feeder. Wolverines prey on hares, rodents and occasionally animals as large as moose given certain snow conditions. They can also prey heavily on domestic sheep and semi-domesticated reindeer.
The wolverine is a nocturnal species (Whitman 1999) with an average life expectancy of 4 to 6 years in the wild, with a maximum of about 13 years (Pasitschniak-Arts and Lariviere 1995). The species reaches its sexual maturity at 2.5 years, breeding occurs in early spring to late fall with litters of 1-5 young (mean litter size is 3 young) born between February and April (Whitman 1999).
Wolverines are thought to have evolved to scavenge from the kills of wild ungulates abandoned by other carnivores such as the lynx and wolf, as well prey animals felled by disease or injury. Wolverines also actively hunt smaller animals such as rodents, hares, musk deer, roe deer and wild sheep; given the appropriate snow conditions they will also hunt larger animals such as moose. Conflicts arise when wolverines prey on domestic livestock such as sheep or semi-domesticated reindeer. Given their dependence on other hunters for much of its scavenged food, wolverines are able to carry and cache large amounts of meat for later consumption.
Within the current range, extensive human activities continue to pressure wolverine populations and habitat (Krebs et al. 2004). Overexploitation through hunting and trapping, as well as predator poisoning programs and resource extraction likely caused wolverine populations to contract in the eastern and south-western portions of their historical range in North America since the early 1900s (Banci 1994).
The wolverine is threatened by fragmented distributions, presumed low genetic diversity, as well as “population control” hunting and conflicts with human settlements resulting from depredation of livestock. While this species inhabits a zone that is particularly affected by climate change (IPCC International Climate Report 2005), habitat change or even loss is not taking place at such a rate to be considered a major threat to the wolverine. Ample forested lands and tundra with suitable prey stocks are available throughout much of its range. The problem is the low rate of human land use expansion into this range, increasing the frequency of interaction with human populations and conflict over livestock depredation. Given the remoteness of these locations, tolerance of wolverines taking livestock is low and in some areas “population control” hunting is used as a proactive means to avoid loss of animals. In Norway, where almost 10,000 sheep are believed to be killed by wolverines each summer, government committees have instituted annual harvest quotas in an effort to control livestock losses; however, these quotas may not be sustainable as they are set very high even in relation to the most liberal estimate of wolverine population size, and it is unclear whether this hunt actually reduces the numbers of sheep and semi-domestic deer lost to predators.
Wolverines are scarce in Europe today. Their continued survival is threatened due to their small and fragmented distribution, and the potential for their future survival may be weakened by the likelihood of low genetic diversity. Habitat loss per se is not a substantial threat to wolverine conservation. Large areas of Norway, Sweden and Finland are still covered by forests and mountains that offer a suitable prey base and habitat for wolverines. The problem is that these are not wilderness areas, and wolverines come into conflict with a low, but crucial, number of human land uses. The fact that there are no large areas within their distribution where there is no conflict potential with sheep or semi domestic reindeer means that human tolerance for wolverines is low. This results in a difficult situation for wildlife managers who are forced to try and balance wolverine conservation with the conflicts they create with livestock. In Norway, farmers no longer use traditional sheep-herding methods that once deterred depredation, so wolverines are often controlled in an effort to protect livestock. Poaching also occurs. In Russia, overharvesting and declines in key prey species are major threats.
1. Scandinavian wolverine population: The species is subject to illegal killings due to depredation conflicts (sheep, domestic reindeer). The scope of this is difficult to quantify. Furthermore wolverines are sensitive to human disturbance (settlements, public and private roads etc.) especially in the vicinity of their denning areas (May et al. 2006).
2. Southern Norwegian wolverine population: The Southern Norwegian wolverine population is subject to illegal killings due to depredation conflicts on sheep. The scope of this is difficult to quantify. Most people in Norway are settled in southern Norway and the wolverines are sensitive to human disturbance (settlements, public and private roads, etc.) especially in the vicinity of their denning areas (May et al. 2006).
3. Swedish forest wolverine population/occurrence: A high degree of genetic similarity among individuals in the two areas indicates inbreeding, possibly including brother-sister matings (Hedmark 2006). Inbreeding depression and demographic stochasticity are therefore likely to be the main threats (Pimm et al. 1988). These forest dwelling wolverines live outside the distribution of “domestic” reindeer, which form the most common prey for wolverines (Landa et al. 1997). Establishment of wolverines in the forest landscape is judged to be a way of reducing conflict with the domestic reindeer industry (Hedmark et al. unpubl. ms, Hedmark 2006).
4. Finnish – Western Russian wolverine population: About half the Finnish wolverine population are living within the reindeer management area in the north (Kojola 2005), thus creating conflict with the domestic reindeer industry (Landa et al. 2000b) with associated illegal killings. The scope of this is unknown. The Russian economic depression during the 1990s is believed to have led to widespread poaching of ungulate game species. Furthermore, it led to a reduction of the domestic reindeer herding industry due to large calf/breeding losses. This is believed to have indirectly negatively affected the wolverine’s populations in the European and most human populated part of Russia. The wolverine's main prey base (wild and domestic reindeer) became less abundant and the population has faced a decrease in numbers and distribution during the last few decades (Landa et al. 1997, Landa et al. 2000a, Novikov 2005). In Russia the wolverine is harvested for fur, and to the best knowledge of the assessors, there are no harvest restrictions. Russia has not yet ratified the Bern Convention.
5. Finnish western wolverine population: It is likely that this small and presumably isolated population will face inbreeding problems (Hedmark 2006) as well as being exposed to demographic stochasticity (Pimm et al. 1988). Inbreeding depression and demographic accidents are therefore main threats. These forest dwelling wolverines live outside the distribution of semi domesticated reindeer, which form the most common prey for wolverines (Landa et al. 1997). Establishment of wolverines in the forest landscape is judged to be a way of reducing conflict with the domestic reindeer industry (Hedmark et al. unpubl. ms, Hedmark 2006).
The wolverine has been petitioned twice for listing under the federal Endangered Species Act in the conterminous United States, but the most recent petition was denied citing lack of information on distribution, habitat requirements, and threats (United States Fish and Wildlife Service 2003). In North America, the eastern wolverine population continues to be Endangered, and the western population remains Special Concern.
The wolverine is recorded from a number of protected areas. However, due to its spatial requirement, very few reserves will contain the full home ranges of more than a small number of individuals (Schreiber et al., 1989).
European range states have different monitoring and management regimes varying from strict protection in Finland and Sweden, licensed harvest and control measurements in Norway to legal harvest year round in Russia.
In North America, wolverine management issues include regulating trapper harvest, preventing human disturbance at denning sites, and mitigating for habitat loss and fragmentation (Krebs et al., 2004).
Key conservation measures that need to be implemented revolve around minimizing conflicts resulting from depredation of livestock, reducing legal and illegal hunting of wolverines, establishing well-planned conservation areas and carrying out surveys to gain a better understanding of the population and ecology of the wolverine.
Farmers and local communities should be educated in and encouraged to adopt husbandry practices that will minimize depredation of livestock thereby reducing conflicts. Economic incentives could encourage farmers to conserve wolverines on their land instead of hunting them. A compensation and education program has been implemented in Sweden with reindeer herders where the herders profit financially from identifying dens on their land and protecting them; similar programs could be applied in more areas of the species range.
Governments and researchers require a more solid knowledge of population dynamics, wolverine-prey relationships, habitat-use and distribution of the wolverine. This information is needed to ensure that legal, government-permitted hunting quotas are appropriate and small, localized, endangered populations are protected. Better enforcement of laws that prohibit hunting of wolverines is required in applicable parts of the species range, with higher penalties to discourage poachers. Governments need also improve coordination between wildlife conservation and agriculture programs to ensure that conservation areas are established in regions with little risk of conflict with farmers and herders.
The wolverine is listed on Appendix II of the Bern Convention and Annex II* and Annex IV of the EU Habitats and Species Directive. European range states have different monitoring and management regimes varying from strict protection in Finland and Sweden, licensed harvest and control measurements in Norway to legal harvest year round in Russia.
1. Scandinavian wolverine population: The Scandinavian wolverine population is covered by both Swedish and Norwegian management regimes, which are quite different. However, both Norwegian and Swedish populations are monitored through annual counting of active natal dens (Landa et al. 1998b) and non-invasive faecal DNA surveys (in southern areas). There is cooperation and data exchange between the two national programmes. The Swedish national interim goal is to reach minimum 90 annual wolverine reproductions (approximately 575 individuals >1 yr of age) (Riksdagen 2000). Sweden has international obligations through the Bern Convention for the conservation of the European wildlife and habitats, the regulation of trade through the European Council Regulation on the protection of species of wild fauna and flora, and the EU habitat directive. The wolverine is in Sweden is officially listed as endangered and is not subject to hunting. However, recently a few family groups have been killed in the purpose of reducing conflict with the domestic reindeer herding industry in northern areas. Norway was recently (2003) divided into 6 different management regions with politically appointed management boards (Miljøverndepartementet 2003). The Norwegian national goal is to control the total population within the limits of 39 yearly active reproductions (21 within the Norwegian part of the Scandinavian wolverine population) (Miljøverndepartementet 2003). The total of 39 breedings equals approximately 250 individuals >1 yr of age. Control measurements, killing of family groups in early spring and licensed harvest is used as a management tool to restrict wolverine distribution and predation on unattended sheep during summer and domestic reindeer all year around. Wolverines in Norway are covered by the Bern Convention (Bern 1979). The wolverines in Norway are officially listed as vulnerable (new official listing is expected by the end of 2006).
2. Southern Norwegian wolverine population: Norway was recently (2003) divided into 6 different management regions. The national goal is to control the Southern Norwegian population (including North Trøndelag County) at maximum 18 yearly active reproductions (approximately 115 individuals >1 yr of age) (Miljøverndepartementet 2003). Control measurements, killing of family groups in early spring and licensed harvest is used as a management tool to restrict wolverine distribution and predation on unattended sheep during summer in southern Norway. Wolverines in Norway are covered by the Bern Convention (Bern 1979). The wolverines in Norway are officially listed as vulnerable (new official listing is expected by the end of 2006).
3. Swedish forest wolverine population/occurrence: Totally protected, also see description for the Scandinavian wolverine population for further details.
4. Finnish – western Russian wolverine population: Management differs in Finland and Russia. In Finland the species is monitored through a national fauna monitoring programme based on tracks crossing fixed 4x4+4 km triangles. Wolverines have been fully protected in Finland since 1982. In Russia the wolverine is monitored via tracking surveys and numbers are estimated based on daily pats and a calculation coefficient (Novikov 1994, Novikov 2005). In Russia wolverines are considered a game/pelt species.
5. Finnish western wolverine population: Wolverines have been fully protected in Finland since 1982. In western Finland, the small introduced subpopulation seems to function without the presence of semi-domesticated reindeer, wolf, or lynx. A research project where nutritional ecology of wolverines within the three areas of wolverine distribution within Finland will be compared has been initiated. A future aim is to develop non-invasive molecular genetic monitoring of the wolverines within Finland similar to the one conducted in Scandinavia (Kojola 2005).
|Citation:||Abramov, A., Belant, J. & Wozencraft, C. 2009. Gulo gulo. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 12 March 2014.|
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