Despotism and Risk of Infanticide Influence Grizzly Bear Den-Site Selection

Libal, Nathan S.; Belant, Jerrold L.; Leopold, Bruce D.; Wang, Guiming; Owen, Patricia

doi:10.1371/journal.pone.0024133

Cited by 48 publications

(46 citation statements)

References 62 publications

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“…Relative influence of standardized covariates for the combined (second step) top models representing patterns of selection of denning sites by brown bears (Ursus arctos) at the home range scale (third order) across the central Brooks Range, Alaska, USA, 2014-2017. The average (31°) and the range (16°-44°) of slopes of dens were similar to other studies (Reynolds et al 1974, Libal et al 2011, 2012 and may represent the range of slopes providing stable and thermally optimal conditions for excavating dens (Reynolds et al 1974, Vroom et al 1980b, Libal et al 2012. Dots represent estimated coefficients, error bars depict the 95% confidence intervals, SLI indicates snow load index, DTD indicates distance to den in previous year, and Salmon indicates distance to salmon stream.…”

Section: Discussionsupporting

confidence: 84%

“…Nevertheless, other studies have shown a relationship between densite selection and forage availability for brown bears (Libal et al 2011, Pigeon et al 2014. We posit that the energetic output for bears to travel between areas with important food resources and den sites is relatively low compared to the energy saved by selecting den features that reduce disturbances and improve thermal insulation over a 6-to 8month hibernation period.…”

Section: Discussionmentioning

confidence: 89%

“…Plot A depicts the full data, which includes all the den-site data, whereas plot B depicts the subset data, which includes only den sites for which the previous year's den site was known. Selection for steeper slopes has also been attributed to increased security (Ciarniello et al 2005, Goldstein et al 2010, Pigeon et al 2016, particularly by females with young avoiding infanticidal males (Libal et al 2011). Covariates were standardized by subtracting the mean and dividing by the standard deviation.…”

Section: Discussionmentioning

confidence: 99%

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Den‐site characteristics and selection by brown bears (Ursus arctos) in the central Brooks Range of Alaska

et al. 2019

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Selection and use of dens is a critical behavioral adaption of bears (Ursus spp.) to survive extended periods of resource limitation. We analyzed selection of den sites by brown bears (Ursus arctos) in an arctic montane environment from 2014 to 2017. We used GPS data from 51 instrumented bears to physically locate, identify, and describe den sites (n = 33) and to quantitatively model the selection of denning habitat (n = 65 dens over 3 yr). We conducted an analysis of den-site selection at the home range (third order) scale using variables describing topographic, vegetative, and spatially-explicit fish and wildlife models. We hypothesized four main factors influence den-site selection by brown bears: (1) physiography, (2) proximity to food resources, (3) thermal insulation, and (4) den-area fidelity. We used kernel density estimates to define space use and conditional logistic regression to estimate den selection within individual home ranges. Brown bears selected den sites on steep slopes (>31°) with high snow load potential near their previously used den site. Our results supported our hypothesis that den selection by brown bears was related to thermal insulation, structural stability, drainage, and den-area fidelity.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

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Den‐site characteristics and selection by brown bears (Ursus arctos) in the central Brooks Range of Alaska

et al. 2019

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“…; Libal et al . ). Spatiotemporal avoidance of infanticidal individuals is an obvious counterstrategy, but conclusive evidence for it is rare and mainly involves group‐living species (Ebensperger & Blumstein ) such as lions ( Panthera leo ) (Pusey & Packer ) and Hanuman langurs ( Presbytis entellus ) (Hrdy ).…”

Section: Introductionmentioning

confidence: 97%

“…; Bellemain, Swenson & Taberlet ; Libal et al . ). Female counterstrategies to NPI in brown bears include direct defence (Craighead, Sumner & Mitchell ), promiscuity and multiple paternity (Bellemain, Swenson & Taberlet ), selecting escape habitat (Pearson ; Swenson ), elusiveness (Dahle & Swenson ) and avoidance of sites with high infanticide risk (e.g.…”

Section: Introductionmentioning

confidence: 97%

Male reproductive strategy explains spatiotemporal segregation in brown bears

Steyaert

Kindberg

Swenson

et al. 2013

Journal of Animal Ecology

119

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1. Spatiotemporal segregation is often explained by the risk for offspring predation or by differences in physiology, predation risk vulnerability or competitive abilities related to size dimorphism.2. Most large carnivores are size dimorphic and offspring predation is often intraspecific and related to nonparental infanticide (NPI). NPI can be a foraging strategy, a strategy to reduce competition, or a male reproductive strategy. Spatiotemporal segregation is widespread among large carnivores, but its nature remains poorly understood.3. We evaluated three hypotheses to explain spatiotemporal segregation in the brown bear, a size-dimorphic large carnivore in which NPI is common; the ‘NPI – foraging/competition hypothesis', i.e. NPI as a foraging strategy or a strategy to reduce competition, the ‘NPI – sexual selection hypothesis’, i.e. infanticide as a male reproductive strategy and the ‘body size hypothesis’, i.e. body-size-related differences in physiology, predation risk vulnerability or competitive ability causes spatiotemporal segregation. To test these hypotheses, we quantified spatiotemporal segregation among adult males, lone adult females and females with cubs-of-the-year, based on GPS-relocation data (2006–2010) and resource selection functions in a Scandinavian population.4. We found that spatiotemporal segregation was strongest between females with cubs-of-the-year and adult males during the mating season. During the mating season, females with cubs-of-the-year selected their resources, in contrast to adult males, in less rugged landscapes in relative close proximity to certain human-related variables, and in more open habitat types. After the mating season, females with cubs-of-the-year markedly shifted their resource selection towards a pattern more similar to that of their conspecifics. No strong spatiotemporal segregation was apparent between females with cubs-of-the-year and conspecifics during the mating and the postmating season.5. The ‘NPI – sexual selection hypothesis’ best explained spatiotemporal segregation in our study system. We suggest that females with cubs-of-the-year alter their resource selection to avoid infanticidal males. In species exhibiting NPI as a male reproductive strategy, female avoidance of infanticidal males is probably more common than observed or reported, and may come with a fitness cost if females trade safety for optimal resources.

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Non‐invasive mark–resight surveys for brown bears: Incorporating spatial information to improve landscape‐scale monitoring of density and distribution

Schmidt,

Deacy,

Hughes

et al. 2023

Ecol Sol and Evidence

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Effective wildlife monitoring and management are reliant on unbiased estimators of population parameters. Most standard survey approaches ignore spatial pattern in the data although spatial relationships can be leveraged to produce more efficient designs for future surveys, thereby reducing project cost. Landscape‐scale surveys for brown bears are notoriously expensive and difficult to complete, leading to the development of a non‐invasive mark–resight aerial survey approach as a practical alternative to more commonly employed approaches for estimating brown bear density across large areas. Here we extend that model to accommodate spatial covariate information and explicitly model residual spatial autocorrelation. Using brown bear survey data from northwestern Alaska, USA from 2015 to 2021, we demonstrate how our extension can be useful in exploring ecological factors related to spatial variation in bear density and detection probability. We found that detection probability was higher in more rugged terrain, and occurrence probability was higher at mid‐elevations where denning habitat was more prevalent and in areas with more salmon streams. The descriptive model of residual autocorrelation confirmed that additional unmeasured factors were associated with bear distribution. While these findings were not unexpected, they are very useful when considering future survey effort. Using this information, we explored a hypothetical redesign of the 2021 brown bear survey that removed 50% of the survey subunits with elevation values below the mean, where bears were least likely to occur. We demonstrated that the resulting estimates were unbiased, suggesting that adopting the spatial approach to analysis could reduce overall project costs by ~20%–30% going forward. Overall, our work indicates that directly accounting for spatial pattern within the non‐invasive mark–resight framework has substantive advantages over the original non‐spatial approach and may be useful in increasing the amount of information available for brown bear populations.

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Despotism and Risk of Infanticide Influence Grizzly Bear Den-Site Selection

Cited by 48 publications

References 62 publications

Den‐site characteristics and selection by brown bears (Ursus arctos) in the central Brooks Range of Alaska

Den‐site characteristics and selection by brown bears (Ursus arctos) in the central Brooks Range of Alaska

Male reproductive strategy explains spatiotemporal segregation in brown bears

Non‐invasive mark–resight surveys for brown bears: Incorporating spatial information to improve landscape‐scale monitoring of density and distribution

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