Bourque Jennifer, Atwood Todd C, Divoky George J, Stewart Connie, McKinney Melissa A
Wildlife and Fisheries Conservation Center Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering University of Connecticut Storrs CT USA.
Alaska Science Center United States Geological Survey Anchorage AK USA.
Ecol Evol. 2020 Jan 29;10(4):2093-2103. doi: 10.1002/ece3.6043. eCollection 2020 Feb.
Polar bears () from the southern Beaufort Sea (SB) subpopulation have traditionally fed predominantly upon ice-seals; however, as the proportion of the subpopulation using onshore habitat has recently increased, foraging on land-based resources, including remains of subsistence-harvested bowhead whales () and colonial nesting seabirds has been observed. Adipose tissue samples were collected from this subpopulation during the springs of 2013-2016 and analyzed for fatty acid signatures. Diet estimates were generated for the proportional consumption of ringed seal (), bearded seal (), and beluga whale (), relative to onshore foods, including bowhead whale remains and seabird, as represented by black guillemot () nestlings and eggs. Quantitative fatty acid signature analysis (QFASA) estimated that the ice-obligate prey, ringed seal, remained the predominant prey species of SB polar bears (46.4 ± 1.8%), with much lower consumption of bearded seal (19.6 ± 2.0%), seabird (17.0 ± 1.2%), bowhead whale (15.0 ± 1.4%), and hardly any beluga whale (2.0 ± 0.5%). Adult and subadult females appeared to depend more on the traditional ringed seal prey than adult and subadult males. Diet estimates of SB polar bears showed significant interannual variability for all prey ( = 3.17, < .001). Longer-term estimates suggested that both types of onshore prey, bowhead whale remains and seabird, have represented a moderate proportion of the food resources used by SB polar bears since at least the start of the 21st Century.
来自波弗特海（SB）南部亚种群的北极熊传统上主要以海豹为食；然而，随着该亚种群使用陆上栖息地的比例最近有所增加，人们观察到它们会觅食陆基资源，包括自给性捕猎的弓头鲸残骸和群居筑巢海鸟。在2013年至2016年春季期间，从该亚种群中采集了脂肪组织样本，并对脂肪酸特征进行了分析。针对环斑海豹、髯海豹和白鲸相对于陆上食物（包括弓头鲸残骸和海鸟，以黑脚三趾鸥雏鸟和卵为代表）的比例消耗情况进行了饮食估算。定量脂肪酸特征分析（QFASA）估计，依赖冰面生存的猎物环斑海豹仍然是波弗特海南部北极熊的主要猎物种类（46.4±1.8%），髯海豹（19.6±2.0%）、海鸟（17.0±1.2%）、弓头鲸（15.0±1.4%）的消耗量要低得多，而白鲸几乎没有（2.0±0.5%）。成年和亚成年雌性似乎比成年和亚成年雄性更依赖传统的环斑海豹猎物。波弗特海南部北极熊的饮食估算显示，所有猎物的年际变化都很显著（F = 3.17，P <.001）。长期估算表明，至少从21世纪初以来，弓头鲸残骸和海鸟这两种陆上猎物在波弗特海南部北极熊所利用的食物资源中都占了相当比例。
