title: Determinants of lifetime reproduction in female brown bears: early body mass, longevity, and hunting regulations.
abstract: In iteroparous mammals, conditions experienced early in life may have long-lasting 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.
authors.affiliation: Faculty of Arts and Sciences, Department of Environmental and Health Studies, Telemark University College, NO-3800 Bø i Telemark, Norway. andreas.zedrosser@hit.no
authors.forename: Andreas
authors.initials: A
authors.lastname: Zedrosser
authors.forename: Fanie
authors.initials: F
authors.lastname: Pelletier
authors.forename: Richard
authors.initials: R
authors.lastname: Bischof
authors.forename: Marco
authors.initials: M
authors.lastname: Festa-Bianchet
authors.forename: Jon E
authors.initials: JE
authors.lastname: Swenson
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology*; D005260:Female; D006802:Human Activities; D006801:Humans; D008136:Longevity / Q000502:physiology*; D011157:Population Dynamics; D012098:Reproduction / Q000502:physiology*; D013548:Sweden; D001503:Ursidae / Q000502:physiology*