Biological and Genetic Peculiarities of Cross-Composed and Aboriginal Beaver Populations in Russia

Saveljev, Alexander P.; Милишников, А. Н.

doi:10.1080/13921657.2002.10512530

Cited by 10 publications

(10 citation statements)

References 6 publications

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“…Similar to our study, it was shown that delayed dispersal could lead to an increased LRS in male Siberian jays (Ekman et al, 1999) and to an increased probability of reproduction in male red wolves (Sparkman et al, 2010). Generally, the annual reproductive success in our study area was very low compared to other Eurasian beaver populations (Halley, 2011;Saveljev & Milishnikov, 2002). This might be due to resource depletion as beavers inhabited the area at least since 1920 (Olstad, 1937) and because the population is saturated (Campbell et al, 2012;Steyaert et al, 2015).…”

Section: Lifetime Reproductive Successsupporting

confidence: 80%

Couch potatoes do better: Delayed dispersal and territory size affect the duration of territory occupancy in a monogamous mammal

Mayer

Zedrosser

Rosell

2017

Ecology and Evolution

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In territorial, socially monogamous species, the establishment and defense of a territory are an important strategy to maximize individual fitness, but the factors responsible for the duration of territory occupancy are rarely studied, especially in long-lived mammals. A long-term monitoring program in southeast Norway spanning over 18 years allowed us to follow the individual life histories of Eurasian beavers (Castor fiber) from adolescence in their natal family group to dispersal and territory establishment until the end of territory occupancy. We investigated whether territory size, resource availability, population density, and dispersal age could explain the duration of territory occupancy, which ranged from 1 to 11 years. The duration of territory occupancy was positively related to dispersal age, suggesting that individuals that delayed dispersal had a competitive advantage due to a larger body mass. This is in support with the maturation hypothesis, which states that an animal should await its physical and behavioral maturation before the acquisition of a territory. Further, we found that individuals that established in medium-sized territories occupied them longer as compared to individuals in small or large territories. This suggests that large territories are more costly to defend due to an increased patrolling effort, and small territories might not have sufficient resources. The lifetime reproductive success ranged from zero to six kits and generally increased with an increasing duration of territory occupancy. Our findings show the importance of holding a territory and demonstrate that dispersal decisions and territory selection have important consequences for the fitness of an individual.

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Section: Lifetime Reproductive Successsupporting

confidence: 80%

Couch potatoes do better: Delayed dispersal and territory size affect the duration of territory occupancy in a monogamous mammal

Mayer

Zedrosser

Rosell

2017

Ecology and Evolution

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“…2005). Nevertheless, reintroduced populations of beavers in Russia, of mixed Pripet and Voronezh stock origin, show a considerably higher average litter size, 3.4, than stocks from only one of these refugia, whether living in the refugium (2.8 and 2.9) or reintroduced elsewhere (2.9 and 3.0; Saveljev & Milishnikov 2002). Unmixed stocks from western refugia show a similar pattern: beavers from the Elbe have an average litter of 1.9 kits (Nolet et al.…”

Section: Inbreeding Fecundity and Genetic Abnormalitiesmentioning

confidence: 99%

“…Similarly, the introduced North American beaver C. canadensis population of the Obor and Ussuri rivers in the Russian Far East derives from a repeatedly bottlenecked population. Dental abnormalities (Saveljev 2001, Saveljev & Milishnikov 2002) are extremely common: 15% of beavers have fewer, and 7% have more than the normal number of teeth, and 30% have tooth caries and gum abnormalities. Defects of the jaws and teeth are relatively easy to detect; it is likely that other, less evident, abnormalities also occur with heightened frequency in unmixed stocks.…”

Section: Inbreeding Fecundity and Genetic Abnormalitiesmentioning

confidence: 99%

Sourcing Eurasian beaver Castor fiber stock for reintroductions in Great Britain and Western Europe

Halley

2010

Mammal Review

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Eurasian beaversCastor fiber, formerly threatened with extinction, have been widely reintroduced since the 1920s. Reintroductions and studies of possible reintroductions are continuing. 2. The International Union for Conservation of Nature (IUCN) guidelines for reintroductions state that 'the source population should ideally be closely related genetically to the original native stock'. 3. Palaeoecological studies suggest that the species survived the last Ice Age in two refugia: in the west in Iberia and Southern France and in the east in the Black Sea region. The post-Ice Age population of Western Europe, including Great Britain, recolonized from the western refugium. Recent mitochondrial deoxyribonucleic acid studies strongly support this view, and extant beaver populations are clearly divided into eastern and western evolutionarily significant units (ESUs). 4. The western ESU is composed of three stocks which survived the 19th and early 20th century as very small, isolated populations. They are very closely related to each other. Each is genetically depauperate, apparently as a result of genetic drift at low population levels. 5. There is evidence of inbreeding depression and of phenotypic abnormalities in beaver populations descended from unmixed stocks. 6. The evidence suggests three coherent management options for sourcing reintroduction stock for Great Britain and for unoccupied areas of western continental Europe. These are (i) use animals from a single western ESU stock; (ii) intentionally mix animals from two or all three of the surviving western ESU stocks; (iii) make an informed exception to the IUCN guidelines and reintroduce animals of mixed eastern and western ESU provenance. 7. These options are discussed with regard to IUCN guidelines, conservation biology and animal welfare considerations. It would be advantageous if a common policy on the origin of reintroduction stock were agreed by the national agencies responsible.

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“…Halley states that the work of Saveljev and Milishnikov (2002) suggests that the differences in litter size observed between ‘mixed’ and ‘unmixed’ populations are due to inbreeding. Fecundity in the North American beaver C. canadensis is affected by many factors, including e.g.…”

Section: Inbreeding Fecundity and Genetic Abnormalitiesmentioning

confidence: 99%

“…2006). Saveljev and Milishnikov (2002) provide figures for average litter size (see their Table 1). However, the method(s) used to determine litter size are not stated, and a statistical analysis of the differences in mean values is not presented.…”

Section: Inbreeding Fecundity and Genetic Abnormalitiesmentioning

confidence: 99%

More genetic data are needed before populations are mixed: response to ‘Sourcing Eurasian beaver Castor fiber stock for reintroductions in Great Britain and Western Europe’

2011

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Halley described three options for sourcing Eurasian beavers Castor fiber for reintroduction in Britain and Western Europe: (i) use animals from populations within a single western evolutionarily significant unit (ESU); (ii) mix animals from two or three western ESUs; and (iii) mix animals from eastern and western ESUs. Option three contravenes International Union for Conservation of Nature guidelines, so debate should focus on options one and two. We believe there is a need for further genetic analysis, before a final decision can be made. This decision should not be heavily influenced by cost or be determined by the genotypes of existing captive or escaped populations.

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Biological and Genetic Peculiarities of Cross-Composed and Aboriginal Beaver Populations in Russia

Cited by 10 publications

References 6 publications

Couch potatoes do better: Delayed dispersal and territory size affect the duration of territory occupancy in a monogamous mammal

Couch potatoes do better: Delayed dispersal and territory size affect the duration of territory occupancy in a monogamous mammal

Sourcing Eurasian beaver Castor fiber stock for reintroductions in Great Britain and Western Europe

More genetic data are needed before populations are mixed: response to ‘Sourcing Eurasian beaver Castor fiber stock for reintroductions in Great Britain and Western Europe’

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