Should I stay or should I go? Natal dispersal in the brown bear

Zedrosser, Andreas; Støen, Ole‐Gunnar; Sæbø, Solve; Swenson, Jon E.

doi:10.1016/j.anbehav.2006.09.015

Cited by 154 publications

(138 citation statements)

References 40 publications

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“…Density dependence in dispersal does not always occur. It was reported in only 16 out of 29 bird studies (Matthysen 2005) and was absent in some studies of small (Rodgers 1990;Hanski et al 1991) and medium-sized mammals (Boutin et al 1985;Holekamp 1986), in large herbivores and in large carnivores (Gese & Mech 1991;Zedrosser et al 2007). A positive relationship between dispersal and density has been reported in birds (13 out of the 16 studies showing density dependence; Matthysen 2005), in lizards (Lena et al 1998), in small rodents (Barash 1973) and in ungulates (Clutton-Brock et al 2002;Fan et al 2003;Catchpole et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Negative density-dependent emigration of males in an increasing red deer population

et al. 2009

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In species with polygynous mating systems, females are regarded as food-limited, while males are limited by access to mates. When local density increases, forage availability declines, while mate access for males may increase due to an increasingly female-biased sex ratio. Density dependence in emigration rates may consequently differ between sexes. Here, we investigate emigration using mark-recovery data from 468 young red deer Cervus elaphus marked in Snillfjord, Norway over a 20-year period when the population size has increased sixfold. We demonstrate a strong negative density-dependent emigration rate in males, while female emigration rates were lower and independent of density. Emigrating males leaving the natal range settled in areas with lower density than expected by chance. Dispersing males moved 42 per cent longer at high density in 1997 (37 km) than at low density in 1977 (26 km), possibly caused by increasing saturation of deer in areas surrounding the marking sites. Our study highlights that pattern of density dependence in dispersal rates may differ markedly between sexes in highly polygynous species. Contrasting patterns reported in small-scale studies are suggestive that spatial scale of density variation may affect the pattern of temporal density dependence in emigration rates and distances.

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Section: Discussionmentioning

confidence: 99%

Negative density-dependent emigration of males in an increasing red deer population

et al. 2009

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“…Because we did not distinguish between dispersing and philopatric individuals, our estimates likely included dispersing bears and, therefore, did not conform to the traditional definition of a home range (Burt 1943). Because sub-adult males disperse farther than sub-adult females (Blanchard and Knight 1991;zedrosser et al 2007), the likely inclusion of dispersing males resulted in a large home range estimate and standard deviation and could explain why our estimate was four times larger than the home range reported for philopatric sub-adult males in Sweden (Dahle et al 2006). the large variation in hourly movement rates by adult and sub-adult males and the conservative nature of the Bonferroni adjustment (Garcia 2004) could have resulted in missing significant differences (type II error).…”

Section: Discussionmentioning

confidence: 99%

Home range, movements, and denning chronology of the Grizzly Bear (<em>Ursus arctos</em>) in west-central Alberta

Graham

Stenhouse

2014

Can Field Nat

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. 2014. Home range, movements, and denning chronology of the Grizzly Bear (Ursus arctos) in west-central Alberta. Canadian Field-naturalist 128(3): 223-234.An understanding of the natural history of the Grizzly Bear (Ursus arctos) is important for recovery planning. We present data on home range size, movements and denning chronology collected using Global Positioning System (GPS) collars on Grizzly Bears in west-central Alberta. Mean annual kernel estimates for adult (1034 ± 656 (SD) km 2 ) and subadult (1298 ± 1207 km 2 ) males were larger than those for females with cubs of the year (213 ± 212 km 2 ) and lone adult females (337 ± 176 km 2 ) but not different from sub-adult females, females with yearlings, or females with ≥ 2-yr old cubs (P > 0.05). Mean rates of movement among female age-reproductive classes were different from each other (Z 9 < 2.70, P > 0.05) but not different from sub-adult males (Z 9 < 2.70, P > 0.05). Rates of movement of adult males were significantly different only from those of females with cubs of the year (Z 9 = 3.94, P = 0.001). the greatest amount of movement occurred in June and the least in october. Bears traveled fastest in the morning and evening and slowest at night. Pregnant females had the longest denning period (175 days, ± 16 days SD). no difference was detected in denning duration among the remaining five age-sex-reproductive classes (P > 0.05). GPS collars provided large location datasets from which accurate home range estimates, hourly movement rates, and precise denning dates were determined. examining similarities and differences in the basic biology of Grizzly Bears from various locations will improve our understanding of the plasticity of this species and the potential impacts of habitat and climate change.

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“…Similarly to other mammals, larger mothers have larger offspring (e.g., Clutton-Brock et al 1988, Wauters et al 1993, Skibiel et al 2009). In addition, larger female yearling brown bears establish their home range closer to or within their natal home range, which probably gives them a reproductive advantage through familiarity with the area and better access to resources facilitated by their mother (Zedrosser et al 2007b). Although compensatory growth can have short-term benefits, it may involve costs that are not evident until much later (Metcalfe and Monaghan 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Because all bears were captured within a two-week period in each study area, we did not adjust mass for capture date. For further details regarding capture and handling of bears, see Arnemo et al (2011) and Zedrosser et al (2007b). Our analyses include only females of known age that were first captured as yearlings.…”

Section: Capturementioning

confidence: 99%

Determinants of lifetime reproduction in female brown bears: early body mass, longevity, and hunting regulations

Zedrosser

Pelletier

Bischof

et al. 2013

Ecology

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Abstract. In iteroparous mammals, conditions experienced early in life may have longlasting effects on lifetime reproductive success. Human-induced mortality is also an important demographic factor in many populations of large mammals and may influence lifetime reproductive success. Here, we explore the effects of early development, population density, and human hunting on survival and lifetime reproductive success in brown bear (Ursus arctos) females, using a 25-year database of individually marked bears in two populations in Sweden. Survival of yearlings to 2 years was not affected by population density or body mass. Yearlings that remained with their mother had higher survival than independent yearlings, partly because regulations prohibit the harvest of bears in family groups. Although mass as a yearling did not affect juvenile survival, it was positively associated with measures of lifetime reproductive success and individual fitness. The majority of adult female brown bear mortality (72%) in our study was due to human causes, mainly hunting, and many females were killed before they reproduced. Therefore, factors allowing females to survive several hunting seasons had a strong positive effect on lifetime reproductive success. We suggest that, in many hunted populations of large mammals, sport harvest is an important influence on both population dynamics and life histories.

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Should I stay or should I go? Natal dispersal in the brown bear

Cited by 154 publications

References 40 publications

Negative density-dependent emigration of males in an increasing red deer population

Negative density-dependent emigration of males in an increasing red deer population

Home range, movements, and denning chronology of the Grizzly Bear (<em>Ursus arctos</em>) in west-central Alberta

Determinants of lifetime reproduction in female brown bears: early body mass, longevity, and hunting regulations

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