Ecological flexibility of brown bears on Kodiak Island, Alaska

Daele, Lawrence J. Van; Barnes, Victor G.; Belant, Jerrold L.

doi:10.2192/ursus-d-10-00022.1

Cited by 30 publications

(42 citation statements)

References 34 publications

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“…Brown bears Ursus arctos are opportunistic omnivores with flexible ecological requirements (Krechmar 1995, Van Daele et al 2012 and are able to change their diet in response to spatial and temporal variation in food resources (Mowat andHeard 2006, Bojarska andSelva 2012). Food abundance can influence their body mass, survival, and reproductive success, as well as movements, and habitat use (Jonkel and Cowan 1971, Rogers 1976, Noyce and Garshelis 1997, Hilderbrand et al 1999, Zedrosser et al 2006, Van Daele et al 2012.…”

mentioning

confidence: 99%

“…Food abundance can influence their body mass, survival, and reproductive success, as well as movements, and habitat use (Jonkel and Cowan 1971, Rogers 1976, Noyce and Garshelis 1997, Hilderbrand et al 1999, Zedrosser et al 2006, Van Daele et al 2012. The period of predenning hyperphagia, during which bears must acquire fat reserves, is particularly important for survival and reproduction (Elowe and Dodge 1989), although the additional importance of protein is now being recognized (López-Alfaro et al 2013.…”

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confidence: 99%

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Seasonal and annual variation in the diet of brown bears Ursus arctos in the boreal forest of southcentral Sweden

Stenset¹,

Lutnæs²,

et al. 2016

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Understanding a species' feeding ecology is essential for successful management and conservation, because food abundance can influence body mass, survival, reproductive success, movements, and habitat use. We describe annual and seasonal variations in the diet of brown bears Ursus arctos in southcentral Sweden, based on analysis of 527 fecal samples from 1994–1996 and 2000–2001. There was distinct seasonal variation in most of the 26 food items we documented. Ungulates, predominantly moose Alces alces, and insects comprised most of the estimated dietary energy content in spring and summer. Insects were represented almost entirely by ants, of which Formica spp. and Camponotus herculeanus were the most common. During autumn, berries dominated the diet. The most important berry species were bilberry Vaccinium myrtillus, crowberry Empetrum hermaphoditum and lingonberry V. vitis‐idaea. We determined berry availability by inventorying 308 random plots three times for two consecutive years. These three berries occurred with great spatial, seasonal and annual variation in abundance. The bears showed the strongest positive preference for bilberries, a lesser positive preference for crowberries, but no preference for lingonberries. The proportion of berries in the autmn diet was stable between years, but the relative importance of the species changed, indicating that bears switched to crowberries when bilberries were less abundant. The effects of predicted future climatic change might have severe effects on the availability of the berries, which is the only important food available for fat acquisition prior to hibernation.

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mentioning

confidence: 99%

mentioning

confidence: 99%

Seasonal and annual variation in the diet of brown bears Ursus arctos in the boreal forest of southcentral Sweden

Stenset¹,

Lutnæs²,

et al. 2016

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“…Despite this population being well‐studied, only partial data were available. CMR surveys and concomitant collection of litter information were regularly collected (Van Daele & Barnes, ), but not enough yearly count data were available for proper modeling. To demonstrate the versatility and adaptability of our IPM approach, we fitted a reduced version of our general model to these data, taking advantage of the connection between CMR reproduction data and litter information.…”

Section: Case Study: Kodiak Brown Bear Populationmentioning

confidence: 99%

“…There were bear research projects on four primary study areas across Kodiak Island from 1982 to 1997, all of which included radio telemetry (Van Daele & Barnes, ). We used comparable capture, handling, and processing techniques in all investigations.…”

Section: Case Study: Kodiak Brown Bear Populationmentioning

confidence: 99%

Using multiple data types and integrated population models to improve our knowledge of apex predator population dynamics

Bled

Belant

Daele

et al. 2017

Ecology and Evolution

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Current management of large carnivores is informed using a variety of parameters, methods, and metrics; however, these data are typically considered independently. Sharing information among data types based on the underlying ecological, and recognizing observation biases, can improve estimation of individual and global parameters. We present a general integrated population model (IPM), specifically designed for brown bears (Ursus arctos), using three common data types for bear (U. spp.) populations: repeated counts, capture–mark–recapture, and litter size. We considered factors affecting ecological and observation processes for these data. We assessed the practicality of this approach on a simulated population and compared estimates from our model to values used for simulation and results from count data only. We then present a practical application of this general approach adapted to the constraints of a case study using historical data available for brown bears on Kodiak Island, Alaska, USA. The IPM provided more accurate and precise estimates than models accounting for repeated count data only, with credible intervals including the true population 94% and 5% of the time, respectively. For the Kodiak population, we estimated annual average litter size (within one year after birth) to vary between 0.45 [95% credible interval: 0.43; 0.55] and 1.59 [1.55; 1.82]. We detected a positive relationship between salmon availability and adult survival, with survival probabilities greater for females than males. Survival probabilities increased from cubs to yearlings to dependent young ≥2 years old and decreased with litter size. Linking multiple information sources based on ecological and observation mechanisms can provide more accurate and precise estimates, to better inform management. IPMs can also reduce data collection efforts by sharing information among agencies and management units. Our approach responds to an increasing need in bear populations’ management and can be readily adapted to other large carnivores.

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“…Brown bears (Ursus arctos) exploit patchy resources available for short periods each year (Elgmork and Kaasa 1992;MacHutchon and Wellwood 2003;Mowat and Heard 2006;Munro et al 2006;Naves et al 2006;Edwards et al 2013). Brown bear diets, however, vary widely among individuals, locations, seasons, and between sexes (Hamilton and Bunnell 1987;Gau et al 2002;Munro et al 2006;Vulla et al 2009;Van Daele et al 2012). While some brown bears are largely herbivorous, consumption of animal protein is linked to increased body mass, population density, and litter size (Hilderbrand et al 1999a, b;Rode et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Use of Arctic ground squirrels (Urocitellus parryii) by brown bears (Ursus arctos)

2014

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Brown bears (Ursus arctos) in the Mackenzie Delta in the Northwest Territories of Canada are at the northern edge of their range and persist in a nutrient poor environment with limited available protein. Arctic ground squirrels (Urocitellus parryii) are widespread across northern Canada and are often cited as an important protein source for brown bears. We hypothesized that Arctic ground squirrels form an important part of brown bear diet in the Mackenzie Delta region, and that their importance varies seasonally, with peak use occurring during bears' pre-dormancy hyperphagic period, as well as annually with fluctuating availability of other food. To investigate the seasonal use of Arctic ground squirrels by brown bears, we used resource selection function analysis to describe habitat use, stable isotope analysis to determine individual trophic level and examine its relationship with habitat use, and GPS satellite telemetry to facilitate site investigations. Arctic ground squirrel habitat was not a significant covariate in resource selection functions for pooled sexes, pooled females, and pooled males. However, at the individual level, bears displayed a range of behaviors from selection against, no selection, to selection for Arctic ground squirrel habitat. We found no significant interannual variation in use of Arctic ground squirrel habitat. Site investigations and stable isotopic values for individual bears also suggest a range of foraging behaviors for Arctic ground squirrels. Individual resource selection models combined with trophic level and site investigations provide support for limited use of Arctic ground squirrels that varied between individuals and provided additional evidence for the diversity of niches exploited by individuals.

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Ecological flexibility of brown bears on Kodiak Island, Alaska

Cited by 30 publications

References 34 publications

Seasonal and annual variation in the diet of brown bears Ursus arctos in the boreal forest of southcentral Sweden

Seasonal and annual variation in the diet of brown bears Ursus arctos in the boreal forest of southcentral Sweden

Using multiple data types and integrated population models to improve our knowledge of apex predator population dynamics

Use of Arctic ground squirrels (Urocitellus parryii) by brown bears (Ursus arctos)

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