Individual patterns of prey selection and dietary specialization in an Arctic marine carnivore
Abstract
The cumulative effect of individual‐level foraging patterns may have important consequences for ecosystem functioning, population dynamics and conservation. Dietary specialization, whereby an individual exploits a subset of resources available to the rest of the population, can develop in response to environmental or intrinsic population factors. However, accurate assessment of individual diets may be difficult because analyses of recent food intake may misrepresent foraging variability within a heterogeneous environment. We used quantitative fatty acid signature analysis (QFASA) and a novel index of longitudinal dietary change to examine the individual foraging patterns of 64 polar bears Ursus maritimus successively sampled in Western and Southern Hudson Bay between 1994–2003. Estimated diets varied between and within age and sex classes, with adult male polar bears consuming significantly more bearded seal Erignathus barbatus than adult female or subadult bears, whose diets were dominated by ringed seal Pusa hispida. Among individual adult males, consumption of bearded seal accounted for 0–98% of the diet and bearded seal consumption was positively correlated with individual dietary specialization, as measured by proportional similarity (PSi) to the rest of the population. Most individual diets were consistent from year‐to‐year and were therefore not a product of short‐term heterogeneity in prey distribution. However, a novel dietary change index indicated that adult male polar bears had the most temporally variable diets with 23% of adult males switching their diet from predominantly ringed seal to predominantly bearded seal or vice versa. We conclude that QFASA is well‐suited to analyses of individual‐level foraging because it reflects an animal's diet over the preceding weeks to months. The subpopulations of bears in this study were near the southern limit of their species range and have experienced negative individual‐ and population‐level impacts related to sea ice loss and climate warming. The tightly constrained diets of some individuals, particularly adult females and subadults, may make them especially sensitive to future climate change.
Number of times cited: 27
- Melissa A. McKinney, Todd C. Atwood, Sara J. Iverson and Elizabeth Peacock, Temporal complexity of southern Beaufort Sea polar bear diets during a period of increasing land use, Ecosphere, 8, 1, (2017).
- APB Carneiro, AS Bonnet-Lebrun, A Manica, IJ Staniland and RA Phillips, Methods for detecting and quantifying individual specialisation in movement and foraging strategies of marine predators, Marine Ecology Progress Series, 578, (151), (2017).
- Linda J. Gormezano, Susan N. Ellis-Felege, David T. Iles, Andrew Barnas and Robert F. Rockwell, Polar Bear Foraging Behavior During the Ice-Free Period in Western Hudson Bay: Observations, Origins, and Potential Significance, American Museum Novitates, 3885, 3885, (1), (2017).
- Solveig Vogt, F. André de Villiers, Flora Ihlow, Dennis Rödder and John Measey, Competition and feeding ecology in two sympatric Xenopus species (Anura: Pipidae), PeerJ, 5, (e3130), (2017).
- Caroline M. Pond, The Evolution of Mammalian Adipose Tissues, Adipose Tissue Biology, 10.1007/978-3-319-52031-5_1, (1-59), (2017).
- David J. Yurkowski, Steve Ferguson, Emily S. Choy, Lisa L. Loseto, Tanya M. Brown, Derek C. G. Muir, Christina A. D. Semeniuk and Aaron T. Fisk, Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators, Ecology and Evolution, 6, 6, (1666-1678), (2016).
- Alysa G. McCall, Nicholas W. Pilfold, Andrew E. Derocher and Nicholas J. Lunn, Seasonal habitat selection by adult female polar bears in western Hudson Bay, Population Ecology, 58, 3, (407), (2016).
- Eero J. Vesterinen, Lasse Ruokolainen, Niklas Wahlberg, Carlos Peña, Tomas Roslin, Veronika N. Laine, Ville Vasko, Ilari E. Sääksjärvi, Kai Norrdahl and Thomas M. Lilley, What you need is what you eat? Prey selection by the bat Myotis daubentonii, Molecular Ecology, 25, 7, (1581-1594), (2016).
- Adam E. Rosenblatt, James C. Nifong, Michael R. Heithaus, Frank J. Mazzotti, Michael S. Cherkiss, Brian M. Jeffery, Ruth M. Elsey, Rachel A. Decker, Brian R. Silliman, Louis J. Guillette, Russell H. Lowers and Justin C. Larson, Factors affecting individual foraging specialization and temporal diet stability across the range of a large “generalist” apex predator, Oecologia, 178, 1, (5), (2015).
- O. A. Filatova, E. A. Borisova, O. V. Shpak, I. G. Meschersky, A. V. Tiunov, A. A. Goncharov, I. D. Fedutin and A. M. Burdin, Reproductively isolated ecotypes of killer whales Orcinus orca in the seas of the Russian Far East, Biology Bulletin, 42, 7, (674), (2015).
- Philip Matich, Jeremy J. Kiszka, Michael R. Heithaus, Johann Mourier and Serge Planes, Short-term shifts of stable isotope (δ13C, δ15N) values in juvenile sharks within nursery areas suggest rapid shifts in energy pathways, Journal of Experimental Marine Biology and Ecology, 465, (83), (2015).
- Jon Aars, Magnus Andersen, Agnès Brenière and Samuel Blanc, White-beaked dolphins trapped in the ice and eaten by polar bears, Polar Research, 34, 1, (26612), (2015).
- Nathalie Pettorelli, Anne Hilborn, Clare Duncan and Sarah M. Durant, Individual Variability, Trait-Based Ecology - From Structure to Function, 10.1016/bs.aecr.2015.01.001, (19-44), (2015).
- Melissa P. Galicia, Gregory W. Thiemann, Markus G. Dyck and Steven H. Ferguson, Characterization of polar bear (Ursus maritimus) diets in the Canadian High Arctic, Polar Biology, 38, 12, (1983), (2015).
- Nicholas W. Pilfold, Andrew E. Derocher and Evan Richardson, Influence of intraspecific competition on the distribution of a wide‐ranging, non‐territorial carnivore, Global Ecology and Biogeography, 23, 4, (425-435), (2013).
- Andrew Robertson, Robbie A. McDonald, Richard J. Delahay, Simon D. Kelly and Stuart Bearhop, Individual foraging specialisation in a social mammal: the European badger (Meles meles), Oecologia, 176, 2, (409), (2014).
- Teresa Catry, José A. Alves, Jennifer A. Gill, Tómas G. Gunnarsson and José P. Granadeiro, Individual specialization in a shorebird population with narrow foraging niche, Acta Oecologica, 56, (56), (2014).
- Julien Terraube, David Guixé and Beatriz Arroyo, Diet composition and foraging success in generalist predators: Are specialist individuals better foragers?, Basic and Applied Ecology, 15, 7, (616), (2014).
- Sandra S. Elvin, The large marine ecosystem approach to assessment and management of polar bears during climate change, Environmental Development, 11, (67), (2014).
- Olga Ferlian and Stefan Scheu, Shifts in trophic interactions with forest type in soil generalist predators as indicated by complementary analyses of fatty acids and stable isotopes, Oikos, 123, 10, (1182-1191), (2013).
- Ian W. Murray, Blair O. Wolf and Brock Fenton, Desert Tortoise (Gopherus agassizii) Dietary Specialization Decreases across a Precipitation Gradient, PLoS ONE, 8, 6, (e66505), (2013).
- Melissa A. McKinney, Sara J. Iverson, Aaron T. Fisk, Christian Sonne, Frank F. Rigét, Robert J. Letcher, Michael T. Arts, Erik W. Born, Aqqalu Rosing‐Asvid and Rune Dietz, Global change effects on the long‐term feeding ecology and contaminant exposures of East Greenland polar bears, Global Change Biology, 19, 8, (2360-2372), (2013).
- Michael J. Hooper, Gerald T. Ankley, Daniel A. Cristol, Lindley A. Maryoung, Pamela D. Noyes and Kent E. Pinkerton, Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks, Environmental Toxicology and Chemistry, 32, 1, (32-48), (2012).
- Bryan J. Macbeth, Marc R. L. Cattet, Martyn E. Obbard, Kevin Middel and David M. Janz, Evaluation of hair cortisol concentration as a biomarker of long‐term stress in free‐ranging polar bears, Wildlife Society Bulletin, 36, 4, (747-758), (2012).
- Nicholas W. Pilfold, Andrew E. Derocher, Ian Stirling, Evan Richardson, Dennis Andriashek and André Chiaradia, Age and Sex Composition of Seals Killed by Polar Bears in the Eastern Beaufort Sea, PLoS ONE, 7, 7, (e41429), (2012).
- DAS Rosen and DJ Tollit, Effects of phylogeny and prey type on fatty acid calibration coefficients in three pinniped species: implications for the QFASA dietary quantification technique, Marine Ecology Progress Series, 467, (263), (2012).
- Dag Vongraven, Jon Aars, Steve Amstrup, Stephen N. Atkinson, Stanislav Belikov, Erik W. Born, Terry D. DeBruyn, Andrew E. Derocher, George Durner, Mike Gill, Nick Lunn, Martyn E. Obbard, Jack Omelak, Nikita Ovsyanikov, Elizabeth Peacock, Evan Richardson, Vicki Sahanatien, Ian Stirling and Øystein Wiig, A circumpolar monitoring framework for polar bears, Ursus, 10.2192/URSUS-D-11-00026.1, 23, sp2, (1-66), (2012).




