Robbins, C. T., C. Lopez-Alfaro, K. D. Rode, Ø. Tøien, and O. L. Nelson. 2012. Hibernation and seasonal fasting in bears: the energetic costs and consequences for polar bears. Journal of Mammalogy 93(6):1493-1503. doi:10.1644/11-MAMM-A-406.1.
Karyn Rode, Ph.D.
Nutritional and physiological ecology of large mammals, anthropogenic effects on large mammals, population ecology of ursids
Biography
Education
Ph.D. Washington State University Zoology
M.S. Washington State University Zoology
B.S. Colorado State University Wildlife Biology
Professional Experience
Mar 2012 - Present Research Wildlife Biologist, Alaska Science Center, US Geological Survey
Oct 2006 - Feb 2012 Wildlife Biologist, US Fish and Wildlife Service Polar Bear Program, Anchorage, Alaska
Jan 2006 - Oct 2006 Research Associate, Cornell University, Forest Elephant program
June 2002 - Dec 2005 Contract wildlife biologist - Alaska Department of Fish and Game/PhD candidate - Washington State University
Professional Activities and/or Memberships
Member of the Scientific working group under the US-Russia polar bear commission
Member of the International Union for the Conservation of Nature's (IUCN) Polar bear specialist group
Secretary/Treasurer of the Alaska chapter of the Wildlife Society 2009-2010
Honors and/or Awards
- 2011 FWS Exceptional performance award
- 2010 Department of Interior STAR award
- 2009 FWS Exceptional performance award
- 2007 Dept of Interior STAR award
Science and Products
Date published: December 15, 2017
Status: Active Distribution and Movements of Polar Bears
Polar bears are tied to the sea ice for nearly all of their life cycle functions. Most important of these is foraging, or access to food. Polar bears almost exclusively eat seals, and they are equally as dependent upon the sea for their nutrition as are seals, whales, and other aquatic mammals. Polar bears are not aquatic, however, and their only access to the seals is from the surface of the...
Date published: December 15, 2017
Status: Active Health and Energetics of Polar Bears
Research in this focal area is centered on (i) collecting data on a variety of systems that help determine and mediate polar bear health and energetics, and (ii) developing monitoring and surveillance programs for detecting changes in population health over time. Additionally, this work will allow us to develop an understanding of how polar bear populations will respond to a variety of...
Date published: July 13, 2017
Status: Active Polar Bear Research
Polar bears (Ursus maritimus) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and...
Year Published: 2020
Catalogue of polar bear (Ursus maritimus) maternal den locations in the Beaufort and Chukchi Seas and nearby areas, 1910–2018
This report presents data on the approximate locations and methods of discovery of 530 polar bear (Ursus maritimus) maternal dens observed in the Beaufort and Chukchi Seas and neighboring areas from 1910 to 2018, and archived partly by the U.S. Geological Survey, Alaska Science Center, and partly by the U.S. Fish and Wildlife Service, Marine...
Durner, George M.; Amstrup, Steven C.; Atwood, Todd C.; Douglas, David C.; Fischbach, Anthony S.; Olson, Jay W.; Rode, Karyn D.; Wilson, Ryan R.View Citation
Durner, G.M., Amstrup, S.C., Atwood, T.C., Douglas, D.C., Fischbach, A.S., Olson, J.W., Rode, K.D., and Wilson, R.R., 2020, Catalogue of polar bear (Ursus maritimus) maternal den locations in the Beaufort and Chukchi Seas and nearby areas, 1910–2018: U.S. Geological Survey Data Series 1121, 12 p., including appendixes, https://doi.org/10.3133/ds1121. [Supersedes USGS Data Series 568.]
Year Published: 2020
The clock keeps ticking: Circadian rhythms of free-ranging polar bears
Life in the Arctic presents organisms with multiple challenges including extreme photic conditions, cold temperatures, and annual loss and daily movement of sea ice. Polar bears (Ursus maritimus) evolved under these unique conditions where they rely on ice to hunt their main prey, seals. However, very little is known regarding the dynamics of...
Ware, Jasmine V.; Rode, Karyn D.; Robbins, Charles T.; Leise, T.; Weil, C.R.; Jansen, Heiko T.View Citation
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Year Published: 2018
Survey-based assessment of the frequency and potential impacts of recreation on polar bears
Conservation plans for polar bears (Ursus maritimus) typically cannot prescribe management actions to address their primary threat: sea ice loss associated with climate warming. However, there may be other stressors that compound the negative effects of sea ice loss which can be mitigated. For example, Arctic tourism has...
Rode, Karyn D.; Fortin, Jennifer K.; Garshelis, Dave; Dyck, Markus; Sahanatien, Vicki; Atwood, Todd C.; Belikov, Stanislav; Laidre, Kristin L.; Miller, Susanne; Obbard, Martyn E.; Vongraven, Dag; Ware, Jasmine V.; Wilder, JamesView Citation
Rode, K. D., J. K. Fortin-Noreus, D. L. Garshelis, M. Dyck, V. Sahanatien, T. C. Atwood, S. E. Belikov, K. L. Laidre, S. Miller, M. E. Obbard, D. Vongraven, J. V. Ware, and J. Wilder. 2018. Survey-based assessment of the frequency and potential impacts of recreation on polar bears. Biological Conservation 227:121-132. doi:10.1016/j.biocon.2018.09.008
Year Published: 2018
High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear
Regional declines in polar bear (Ursus maritimus) populations have been attributed to changing sea ice conditions, but with limited information on the causative mechanisms. By simultaneously measuring field metabolic rates, daily activity patterns, body condition, and foraging success of polar bears moving on the spring sea ice, we found that high...
Pagano, Anthony M.; Durner, George M.; Rode, Karyn D.; Atwood, Todd C.; Atkinson, Stephen N.; Peacock, Elizabeth; Costa, Daniel P.; Owen, Megan A.; Williams, Terrie M.View Citation
Pagano, A.M., G.M. Durner, K.D. Rode, T.C. Atwood, S.N. Atkinson, E. Peacock, D.P. Costa, M.A. Owen, and T.M. Williams. 2018. High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear. Science 359:568-572.
Year Published: 2018
Den phenology and reproductive success of polar bears in a changing climate
Synchrony between reproduction and food availability is important in mammals due to the high energetic costs of gestation and lactation. Female polar bears (Ursus maritimus) must accumulate sufficient energy reserves during spring through autumn to produce and nurse cubs during the winter months in snow dens. Adequate time in a den is important to...
Rode, Karyn D.; Olson, Jay; Eggett, Dennis L.; Douglas, David C.; Durner, George M.; Atwood, Todd C.; Regehr, Eric V.; Wilson, Ryan R.; Smith, Tom; St. Martin, MichelleView Citation
Rode, K.D., J. Olson, D. Eggett, D.C. Douglas, G.M. Durner, T.C. Atwood, E.V. Regehr, R.R. Wilson, T. Smith, and M.St. Martin. 2018. Denning phenology and polar bear reproductive success in a changing climate. Journal of Mammalogy 99:16-26.
Year Published: 2018
Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus...
Rode, Karyn D.; Wilson, Ryan R.; Douglas, David C.; Muhlenbruch, Vanessa L; Atwood, Todd C.; Regehr, Eric V.; Richardson, Evan; Pilfold, Nicholas; Derocher, Andrew E.; Durner, George M.; Stirling, Ian; Amstrup, Steven C.; St Martin, Michelle; Pagano, Anthony M.; Simac, Kristin S.View Citation
Rode KD, Wilson RR, Douglas DC,
et al. Spring fasting behavior in a marine apex predator
provides an index of ecosystem productivity. Glob Change
Biol. 2017;00:1–14. https://doi.org/10.1111/gcb.13933
Year Published: 2017
Evaluating methods to assess the body condition of female polar bears
An animal's body condition provides insight into its health, foraging success, and overall fitness. Measures of body composition including proportional fat content are useful indicators of condition. Isotopic dilution is a reliable non-destructive method for estimating the body composition of live mammals, but can require prolonged handling times...
Pagano, Anthony M.; Rode, Karyn D.; Atkinson, Stephen N.View Citation
Pagano, A.M., K.D. Rode, and S.N. Atkinson. 2017. Evaluating methods to assess the body condition of female polar bears. Ursus 28:171-181.
Year Published: 2017
Polar bears, Ursus maritimus
Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the...
Rode, Karyn D.; Stirling, IanView Citation
Rode, K.D., and I. Stirling. 2017. Polar bears. In: Encyclopedia of Marine Mammals, 3rd edition. B. Wursig, J.G.M. Thewissen, and K. Kovacs (eds). Academic Press.
Year Published: 2017
Harvesting wildlife affected by climate change: a modelling and management approach for polar bears
The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes...
Regehr, Eric V.; Wilson, Ryan R.; Rode, Karyn D.; Runge, Michael C.; Stern, HarryView Citation
Regehr, E. V., Wilson, R. R., Rode, K. D., Runge, M. C. and Stern, H. L. (2017), Harvesting wildlife affected by climate change: a modelling and management approach for polar bears. J Appl Ecol.
Year Published: 2017
Simultaneous estimation of diet composition and calibration coefficients with fatty acid signature data
Knowledge of animal diets provides essential insights into their life history and ecology, although diet estimation is challenging and remains an active area of research. Quantitative fatty acid signature analysis (QFASA) has become a popular method of estimating diet composition, especially for marine species. A primary assumption of QFASA is...
Bromaghin, Jeffrey F.; Budge, Suzanne M.; Thiemann, Gregory W.; Rode, Karyn D.View Citation
Bromaghin J. F., S. M. Budge, G. W. Thiemann, and K. D. Rode. 2017. Simultaneous estimation of diet composition and calibration coefficients with fatty acid signature data. Ecology and Evolution 7:6103-6113.
Year Published: 2017
Habitat degradation affects the summer activity of polar bears
Understanding behavioral responses of species to environmental change is critical to forecasting population-level effects. Although climate change is significantly impacting species’ distributions, few studies have examined associated changes in behavior. Polar bear (Ursus maritimus) subpopulations have varied in their near-term responses to sea...
Ware, Jasmine V.; Rode, Karyn D.; Bromaghin, Jeffrey F.; Douglas, David C.; Wilson, Ryan R.; Regehr, Eric V.; Amstrup, Steven C.; Durner, George M.; Pagano, Anthony M.; Olson, Jay; Robbins, Charles T.; Jansen, Heiko TView Citation
Ware, J.V., Rode, K.D., Bromaghin, J.F., Douglas, D.C., Wilson, R.R., Regehr, E.V., Amstrup, S.C., Durner, G.M., Pagano, A.M., Olson, J., Robbins, C.T., and Jansen, H.T., 2017, Oecologia. vol. 184, no. 1, p. 87-99. doi: 10.1007/s00442-017-3839-y
Year Published: 2017
Using tri-axial accelerometers to identify wild polar bear behaviors
Tri-axial accelerometers have been used to remotely identify the behaviors of a wide range of taxa. Assigning behaviors to accelerometer data often involves the use of captive animals or surrogate species, as their accelerometer signatures are generally assumed to be similar to those of their wild counterparts. However, this has rarely been tested...
Pagano, Anthony M.; Rode, Karyn D.; Cutting, A.; Owen, M.A.; Jensen, S.; Ware, J.V.; Robbins, C.T.; Durner, George M.; Atwood, Todd C.; Obbard, M.E.; Middel, K.R.; Thiemann, G.W.; Williams, T.M.Attribution: Alaska Science Center, Ecosystems, Region 11: Alaska, Advanced Research Computing (ARC)
View Citation
Pagano, A.M., Rode, K.D., Cutting, A., Owen, M.A., Jensen, S., Ware, J.V., Robbins, C.T., Durner, G.M., Atwood, T.C., Obbard, M.E., Middel, K.R., Thiemann, G.W., and Williams, T.M. 2017. Using tri-axial accelerometers to identify wild polar bear behaviors: Endangered Species Research vol. 32, p. 19-33. - DOI: https://doi.org/10.3354/esr00779
Pre-USGS Publications
Whiteman, J. P., K. A. Greller, H. J. Harlow, L. A. Felicetti, K. D. Rode, and M. Ben-David. 2012. Carbon isotopes in exhaled breath track metabolic substrates in brown bears (Ursus arctos). Journal of Mammalogy 93:413-421. doi:10.1644/11-MAMM-S-178.1.
Gleason, J. S. and K. D. Rode. 2009. Polar bear distribution and habitat association reflect long-term changes in fall sea ice conditions in the Alaskan Beaufort Sea. Arctic 62(4):405-417.
Schliebe, S. L., K. D. Rode, J. S. Gleason, J. Wilder, K. M. Proffitt, T. J. Evans, and S. Miller. 2008. Effects of sea ice extent and food availability on spatial and temporal distribution of polar bears during the fall open-water period in the Southern Beaufort Sea. Polar Biology 31(8):999-1010. doi:10.1007/s00300-008-0439-7.
Stirling, I., A. E. Derocher, W. Gough, and K. D. Rode. 2008. Response to Dyck et al. (2007) on polar bears and climate change in western Hudson Bay. Ecological Complexity 5(3):193-201. doi:10.1016/j.ecocom.2008.01.004.
Polar bears in the southern Beaufort Sea III: Stature, mass, and cub recruitment in relationship to time and sea ice extent between 1982 and 2006
Rode, K. D., S. C. Amstrup, and E. V. Regehr. 2007. Polar bears in the southern Beaufort Sea III: Stature, mass, and cub recruitment in relationship to time and sea ice extent between 1982 and 2006. USGS Administrative Report, 31 p.
Robbins, C. T., J. K. Fortin, K. D. Rode, S. D. Farley, L. A. Shipley, and L. A. Felicetti. 2007. Optimizing protein intake as a foraging strategy to maximize mass gain in an omnivore. Oikos 116(10):1675-1682. doi:10.1111/j.0030-1299.2007.16140.x.
Fortin, J. K., S. D. Farley, C. T. Robbins, and K. D. Rode. 2007. The role of salmon and berries in determining fall weight gains in brown bears. Ursus 18(1):19-29. doi:10.2192/1537-6176(2007)18[19:DASOBS]2.0.CO;2.
Rode, K. D., S. D. Farley, and C. T. Robbins. 2006. Behavioral responses of brown bears mediate nutritional impacts of experimentally introduced tourism. Biological Conservation 133(1):70-80. doi:10.1016/j.biocon.2006.05.021.
Rode, K. D., C. A. Chapman, L. D. McDowell, and C. A. Stricker. 2006. Nutritional mechanisms of population regulation across habitats and logging intensities in redtail monkeys (Cercopithecus ascanius). Biotropica 38:625-634. doi:10.1111/j.1744-7429.2006.00183.x.
Rode, K. D., P. I. Chiyo, C. A. Chapman, and L. D. McDowell. 2006. Nutritional ecology of elephants in Kibale National Park, Uganda, and its relationship with crop raiding behaviour. Journal of Tropical Ecology 22(4):441-449. doi:10.1017/S0266467406003233. https://doi.org/10.1017/S0266467406003233
Rode, K. D., S. D. Farley, and C. T. Robbins. 2006. Sexual dimorphism, reproductive strategy, and human activities determine resource use by brown bears. Ecology 87(10):2636-2646. doi:10.1890/0012-9658(2006)87[2636:SDRSAH]2.0.CO;2.
The role of sugar content in diet selection in redtail and red colobus monkeys
Danish, L., C. A. Chapman, C. O'Driscoll Worman, K. D. Rode, and M. B. Hall. 2006. The role of sugar content in diet selection in redtail and red colobus monkeys. In Feeding Ecology in apes and other primates. Cambridge University Press, UK.
Chapman, C. A., L. J. Chapman, K. D. Rode, and L. D. McDowell. 2003. Variation in the nutritional value of primate foods: Among trees, time periods, and areas. International Journal of Primatology 24(2):317-337. doi:10.1023/A:1023049200150.
Rode, K. D., C. A. Chapman, L. J. Chapman, and L. D. McDowell. 2003. Mineral resource availability and consumption by colobus monkeys in Kibale National Park, Uganda. International Journal of Primatology 24(3):541-573. doi:10.1023/A:1023788330155.
Variation in the Diets of Cercopithecus Species: Differences Within Forests, Among Forests, and Across Species
Chapman, C. A., L. J. Chapman, M. Cords, M. Gauthua, A. Gautier-Hion, J. E. Lambert, K. D. Rode, C. E. G. Tutin, and L. J. T. White. 2002. Variation in the Diets of Cercopithecus Species: Differences Within Forests, Among Forests, and Across Species. In The Guenons: Diversity and Adaptation in African Monkeys. M. Glenn and M. Cords (eds.). Plenum Press New York City, NY, USA.
Rode, K. D., C. T. Robbins, and L. A. Shipley. 2001. The constraints on herbivory by bears. Oecologia 128(1):62-71. doi:10.1007/s004420100637.
Rode, K. D. and C. T. Robbins. 2000. Why bears consume mixed diets during fruit abundance. Canadian Journal of Zoology 78(9):1-6. doi:10.1139/z00-082.
Voorhees, H., R. Sparks, H. P. Huntington, and K. D. Rode. 2014. Traditional knowledge of polar bears (Ursus maritimus) in Northwestern Alaska. Arctic 67(4). doi:10.14430/arctic4425.
Erlenbach, J. A., K. D. Rode, D. Raubenheimer, and C. M. Robbins. 2014. Macronutrient optimization and energy maximization determine diets of brown bears. Journal of Mammalogy 95(1):160-168. doi:10.1644/13-MAMM-A-161.
Date published: April 1, 2015
Polar Bears Unlikely to Thrive on Land-based Foods
ANCHORAGE, Alaska — A team of scientists led by the U.S. Geological Survey found that polar bears, increasingly forced on shore due to sea ice loss, may be eating terrestrial foods including berries, birds and eggs, but any nutritional gains are limited to a few individuals and likely cannot compensate for lost opportunities to consume their traditional, lipid-rich prey—ice seals.