Reproductive Rates of Beaver in Newfoundland

Payne, Neil F.

doi:10.2307/3801437

Cited by 20 publications

(14 citation statements)

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“…In the data collected from 1969 to 1971, the mean number of foetuses was 4.7 (Lahti & Helminen, 1974). In general, mean litter size in North America seems to increase towards higher latitudes: Mississippi 2.6 (Wigley et al, 1983), California 2.3 (Busher, 1987), Wisconsin 3.9 (Peterson & Payne, 1986), Newfoundland 2.9 (Payne, 1984a) and Alaska 3.1 (Boyce, 1981) per female. Mean litter size of Canadian beavers in Russian Carelia, originating from the Finnish population, is 3.3 (Danilov, 1995), paralleling our results.…”

Section: Discussionmentioning

confidence: 91%

“…Mean litter size of Canadian beavers in Russian Carelia, originating from the Finnish population, is 3.3 (Danilov, 1995), paralleling our results. In general, mean litter size in North America seems to increase towards higher latitudes: Mississippi 2.6 (Wigley et al, 1983), California 2.3 (Busher, 1987), Wisconsin 3.9 (Peterson & Payne, 1986), Newfoundland 2.9 (Payne, 1984a) and Alaska 3.1 (Boyce, 1981) per female. The pregnancy rate in our study (72.5%) is a little higher than the ones reported in North America (Newfoundland 70%, Payne, 1984a;Wisconsin 58%, Peterson & Payne, 1986).…”

Section: Discussionmentioning

confidence: 96%

“…In general, mean litter size in North America seems to increase towards higher latitudes: Mississippi 2.6 (Wigley et al, 1983), California 2.3 (Busher, 1987), Wisconsin 3.9 (Peterson & Payne, 1986), Newfoundland 2.9 (Payne, 1984a) and Alaska 3.1 (Boyce, 1981) per female. The pregnancy rate in our study (72.5%) is a little higher than the ones reported in North America (Newfoundland 70%, Payne, 1984a;Wisconsin 58%, Peterson & Payne, 1986). The bulk of the Finnish Canadian beaver population originates from only two pairs (seven individuals introduced in total), whose offspring were further reintroduced to different parts of the country (Lahti & Helminen, 1974;Ermala, Helminen & Lahti, 1989).…”

Section: Discussionmentioning

confidence: 96%

“…In general, reproductive value ®rst rises and then falls with age (Charlesworth, 1980). According to Wigley et al (1983), reproductive success of Canadian beavers is not dependent on age, whereas Payne (1984a) states that mean litter size increases until 9.5 years of age. He also detected high between-year variation in reproductive success in old females.…”

Section: Discussionmentioning

confidence: 99%

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Costs of reproduction in introduced female Canadian beavers (Castor canadensis)

Ruusila¹,

Ermala²,

Hyvärinen

2000

Journal of Zoology

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In iteroparous organisms, maximum lifetime reproductive success is achieved through multiple successful breeding attempts. Therefore one of an individual's major life-history decisions is the allocation of resources between current and future reproduction. We studied the production of foetuses in the introduced female Canadian beaver Castor canadensis in Finland in 1992±93. The number of foetuses produced in 1993 was negatively correlated with the number produced in the previous year, irrespective of female age. Females that bred only in 1993 tended to produce more foetuses in that year than females that had reproduced in both years. However, the total number of foetuses produced was higher in females that had young in both years, stressing the importance of multiple breeding attempts in maximizing lifetime reproductive success. Despite the small size of the founder population in Finland, mean litter size and pregnancy rates were not different from North American populations.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Costs of reproduction in introduced female Canadian beavers (Castor canadensis)

Ruusila¹,

Ermala²,

Hyvärinen

2000

Journal of Zoology

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“…The natality rate of breeding females (3.6 kits/ad F) on the UCCA was within the reported range of 2.6 (Wigley et al 1983) to 4.0 (Dieter 1992, McTaggart andNelson 2003) from other beaver studies, but only 36% of adult females were bred. Regarding kit survival, Payne (1984) found kit survival to be 48% (1.8 kits/colony), and McTaggart and Nelson (2003) reported kit survival at 43% (1.7 kits/colony). Both studies estimated a 6-month (spring-fall) kit-survival percentage.…”

Section: Natality and Apparent Kit Survivalmentioning

confidence: 99%

Demography of Unexploited Beavers in Southern Illinois

Bloomquist

Nielsen

2010

J Wildl Manag

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Beavers (Castor canadensis) are important in ecosystems and to humans. Although beavers are increasingly protected from harvest, relatively few studies of unexploited beaver populations have been reported. Furthermore, few radiotelemetry studies exist for beavers because no practical method of attaching a radiotransmitter to beavers was available until recently. We used radiotelemetry, remote videography, and trapping data to quantify survival, dispersal, and natality of unexploited beavers in southern Illinois, USA, during 2004 to 2006. Beaver colony density was one of the highest reported in the wildlife literature at 3.27 colonies/km2. We monitored 62 beavers for survival; all mortalities (n = 15) occurred during the fall and winter seasons. The pooled annual survival rate for adult and juvenile females was (x̄±SE) 0.76±0.05. Annual survival rates for adult and juvenile males were 0.87±0.04 and 0.55±0.07, respectively. Seasonal survival only differed among sex classes and age classes during the fall. Dispersal rates for juvenile beavers ranged from 0.38±0.13 to 0.59±0.13 and did not vary by sex or age. To quantify natality and recruitment, we captured and euthanized 79 beavers adjacent to our live‐capture area; we found a low pregnancy rate of adult females (36%), and no juveniles were bred. Natality of bred females was 3.6 offspring per adult female, and 0.36 kits were recruited per adult female. Apparent kit survival was 28%. Our research provides information to wildlife managers about beaver demographics for a high‐density population, based on relatively large sample sizes and novel research techniques for the species.

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Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Johnson‐Bice

Ferguson

Erb

et al. 2020

Ecological Applications

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Over the past two decades, there have been numerous calls to make ecology a more predictive science through direct empirical assessments of ecological models and predictions. While the widespread use of model selection using information criteria has pushed ecology toward placing a higher emphasis on prediction, few attempts have been made to validate the ability of information criteria to correctly identify the most parsimonious model with the greatest predictive accuracy. Here, we used an ecological forecasting framework to test the ability of information criteria to accurately predict the relative contribution of density dependence and density-independent factors (forage availability, harvest, weather, wolf [Canis lupus] density) on inter-annual fluctuations in beaver (Castor canadensis) colony densities. We modeled changes in colony densities using a discrete-time Gompertz model, and assessed the performance of four models using information criteria values: density-independent models with (1) and without (2) environmental covariates; and density-dependent models with (3) and without (4) environmental covariates. We then evaluated the forecasting accuracy of each model by withholding the final one-third of observations from each population and compared observed vs. predicted densities. Information criteria and our forecasting accuracy metrics both provided strong evidence of compensatory density dependence in the annual dynamics of beaver colony densities. However, despite strong within-sample performance by the most complex model (density-dependent with covariates) as determined using information criteria, hindcasts of colony densities revealed that the much simpler density-dependent model without covariates performed nearly as well predicting out-of-sample colony densities. The hindcast results indicated that the complex model over-fit our data, suggesting that parameters identified by information criteria as important predictor variables are only marginally valuable for predicting landscapescale beaver colony dynamics. Our study demonstrates the importance of evaluating ecological models and predictions with long-term data and revealed how a known limitation of information criteria (over-fitting of complex models) can affect our interpretation of ecological dynamics. While incorporating knowledge of the factors that influence animal population dynamics can improve population forecasts, we suggest that comparing forecast performance metrics can likewise improve our knowledge of the factors driving population dynamics.

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Reproductive Rates of Beaver in Newfoundland

Cited by 20 publications

References 0 publications

Costs of reproduction in introduced female Canadian beavers (Castor canadensis)

Costs of reproduction in introduced female Canadian beavers (Castor canadensis)

Demography of Unexploited Beavers in Southern Illinois

Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

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