The importance of meat, particularly salmon, to body size, population productivity, and conservation of North American brown bears

@article{Hilderbrand1999TheIO,
  title={The importance of meat, particularly salmon, to body size, population productivity, and conservation of North American brown bears},
  author={Grant V. Hilderbrand and Charles C. Schwartz and Charles T. Robbins and Michael E. Jacoby and Thomas A. Hanley and Stephen M Arthur and Christopher Servheen},
  journal={Canadian Journal of Zoology},
  year={1999},
  volume={77},
  pages={132-138}
}
We hypothesized that the relative availability of meat, indicated by contribution to the diet, would be positively related to body size and population productivity of North American brown, or grizzly, bears (Ursus arctos). Dietary contributions of plant matter and meat derived from both terrestrial and marine sources were quantified by stable-isotope analysis (δ13C and δ15N) of hair samples from 13 brown bear populations. Estimates of adult female body mass, mean litter size, and population… 

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References

SHOWING 1-10 OF 49 REFERENCES
USE OF STABLE ISOTOPES TO DETERMINE DIETS OF LIVING AND EXTINCT BEARS
TLDR
The potential use of stable-isotope analyses (δ13C and δ15N) to estimate bear diets was assessed in 40-day feeding trials using American black bears (Ursus americanus) and brown bears of Chichagof and Admiralty islands, Alaska.
Black Bear Reproductive Rate Relative to Body Weight in Hunted Populations
Litter size, natality (cubs per adult female per year), and maturation rate are positively related to body weights of adult males and females. This is shown by regressions of reproductive parameters
Seasonal changes in diets of coastal and riverine mink: the role of spawning Pacific salmon
TLDR
It is indicated that riverine mink depended on salmon (carcasses and fry), with little seasonal or individual var...
Reproductive biology of female black bears in relation to body mass in early winter
TLDR
Litter size was influenced by maternal condition in early winter, and overwinter loss of mass greater for females producing litters of three and four young, and for a particular litter size, heavier females tended to produce more male young than expected from an equal sex ratio.
Grizzly Bear Reproductive Rate Relative to Body Size
TLDR
To the extent that IBI and AFW are inversely related to maturation rates to weaning and adulthood, respectively, these results indicate a positive relationship between maturation rate and BS in a population, which would facilitate management of bears.
Possible Impacts of Hunting on the Grizzly/Brown Bear, a Threatened Species
Is hunting detrimental to bear populations? Or do harvests stimulate compensatory reproduction and decrease natural mortality among the survivors? When the literature was reviewed to evaluate support
The diet of grizzly bears in the Flathead River drainage of southeastern British Columbia
TLDR
The hypothesis that a favourable food base in the Flathead is partially responsible for the high density of bears found there is supported by the analysis of 1100 feces or scats.
Using stable carbon (δ13C) and nitrogen (δ15N) isotopes to infer trophic relationships among black and grizzly bears in the upper Columbia River basin, British Columbia
TLDR
Female grizzly bears, however, had lower δ15N values in their hair than the other groups of bears, indicating either less animal protein in their diet or a reliance on foods more depleted in 15N, possibly related to altitude.
Effects of mast and berry crop failures on survival, growth and reproductive success of black bears
TLDR
Existing reports do not support the popular notion that black bears are able to secure an adequate diet each year, and instead of limiting populations below densities that can be supported by long term food supplies, social order may permit higher densities than otherwise might be possible.
The effects of prolonged fasting of the body composition and reproductive success of female polar bears (Ursus maritimus)
TLDR
Pupils that enter maternity dens in late summer/autumn may fast for up to 8 months in addition to meeting the nutritional demands of gestation and lactation, and the nutritional costs of this prolonged 'reproductive fast' are quantified and the effect of variation in maternal body condition on reproductive success is examined.
...
...