stable isotopes

Legacy ID: 
5 244
Publication Title: 

Age-specific vibrissae growth rates: A tool for determining the timing of ecologically important events in Steller sea lions

Authors: 
Rea, L.D., A.M. Christ, A.B. Hayden, V.K. Stegall, S.D. Farley, C.A. Stricker, J.E. Mellish, J.M. Maniscalco, J.N. Waite, V.N. Burkanov, and K.W. Pitcher
Publication Date: 
2015
Parent Publication Title: 
Marine Mammal Science
Publication Type: 
Archive number: 
2015/0038 FORT
States: 

Pub Abstract: 

Steller sea lions (SSL; Eumetopias jubatus) grow their vibrissae continually, providing a multiyear record suitable for ecological and physiological studies based on stable isotopes. An accurate age-specific vibrissae growth rate is essential for registering a chronology along the length of the record, and for interpreting the timing of ecologically important events. We utilized four methods to estimate the growth rate of vibrissae in fetal, rookery pup, young-of-the-year (YOY), yearling, subadult, and adult SSL. The majority of vibrissae were collected from SSL live-captured in Alaska and Russia between 2000 and 2013 (n = 1,115), however, vibrissae were also collected from six adult SSL found dead on haul-outs and rookeries during field excursions to increase the sample size of this underrepresented age group. Growth rates of vibrissae were generally slower in adult (0.44 +/- 0.15 cm/mo) and subadult (0.61 +/- 0.10 cm/mo) SSL than in YOY (0.87 +/- 0.28 cm/mo) and fetal (0.73 +/- 0.05 cm/mo) animals, but there was high individual variability in these growth rates within each age group. Some variability in vibrissae growth rates was attributed to the somatic growth rate of YOY sea lions between capture events (P = 0.014, r2 = 0.206, n = 29).

Publication Title: 

Individual specialization in the foraging habits of female bottlenose dolphins living in a trophically diverse and habitat rich estuary

Authors: 
Rossman, S., P.H. Ostrom, M. Stolen, N.B. Barros, H. Gandhi, C.A. Stricker, and R.S. Wells
Publication Date: 
2015
Parent Publication Title: 
Oecologia
Publication Type: 
Archive number: 
2015/0028 FORT
States: 

Pub Abstract: 
Publication Title: 

Stable isotope values in pup vibrissae reveal geographic variation in diets of gestating Steller sea lions Eumetopias jubatus

Authors: 
Scherer, R.D., A.C. Doll, L.D. Rea, A.M. Christ, C.A. Stricker, B. Witteveen, T.C. Kline, C.M. Kurle, and M.B. Wunder
Publication Date: 
2015
Parent Publication Title: 
Marine Ecology Progress Series
Publication Type: 
Archive number: 
2015/0024 FORT
States: 

Pub Abstract: 
Publication Title: 

Stable carbon and nitrogen isotope trophic enrichment factors for Steller sea lion vibrissae relative to milk and fish/invertebrate diets

Authors: 
Stricker, C.A., A.M. Christ, M.B. Wunder, A.C. Doll, S.D. Farley, L.D. Rea, D.A.S. Rosen, R.D. Scherer, and D.J. Tollit
Publication Date: 
2015
Parent Publication Title: 
Marine Ecology Progress Series
Publication Type: 
Archive number: 
2015/0014 FORT
States: 

Pub Abstract: 
Publication Title: 

Use of 2H and 18O stable isotopes to investigate water sources for different ages of Populus euphratica along the lower Heihe River

Authors: 
Liu, S., Y. Chen, Y. Chen, J.M. Friedman, and G. Fan
Parent Publication Title: 
Ecological Research
Publication Type: 
Archive number: 

Pub Abstract: 
Publication Title: 

Seasonal persistence of marine-derived nutrients in south-central Alaskan salmon streams

Authors: 
Rinella, D.J., M.S. Wipfli, C.M. Walker, C.A. Stricker, and R.A. Heintz
Publication Date: 
2013
Updated Date (text): 
2013-12-03
Parent Publication Title: 
Ecosphere
Publication Type: 
Archive number: 
2013/0066 FORT
States: 

Pub Abstract: 

Spawning salmon deliver annual pulses of marine-derived nutrients (MDN) to riverine ecosystems around the Pacific Rim, leading to increased growth and condition in aquatic and riparian biota. The influence of pulsed resources may last for extended periods of time when recipient food webs have effective storage mechanisms, yet few studies have tracked the seasonal persistence of MDN. With this as our goal, we sampled stream water chemistry and selected stream and riparian biota spring through fall at 18 stations (in six watersheds) that vary widely in spawner abundance and at nine stations (in three watersheds) where salmon runs were blocked by waterfalls. We then developed regression models that related dissolved nutrient concentrations and biochemical measures of MDN assimilation to localized spawner density across these 27 stations. Stream water ammonium-N and orthophosphate-P concentrations increased with spawner density during the summer salmon runs, but responses did not persist into d15 the following fall. The effect of spawner density on N in generalist macroinvertebrates and three independent MDN metrics (d15N, d34S, and x3:x6 fatty acids) in juvenile Dolly Varden (Salvelinus malma) was positive and similar during each season, indicating that MDN levels in biota increased with spawner abundance and were maintained for at least nine months after inputs. Delta 15N in a riparian plant, horsetail (Equisetum fluviatile), and scraper macroinvertebrates did not vary with spawner density in any season, suggesting a lack of MDN assimilation by these lower trophic levels. Our results demonstrate the ready assimilation of MDN by generalist consumers and the persistence of this pulsed subsidy in these organisms through the winter and into the next growing season.

Publication Title: 

Continental-scale, seasonal movements of a heterothermic migratory tree bat

Authors: 
Cryan, P.M., C.A. Stricker, and M.B. Wunder
Publication Date: 
2014
Updated Date (text): 
2013-09-24
Parent Publication Title: 
Ecological Applications
Publication Type: 
Archive number: 
2014/0033 FORT

Pub Abstract: 

Long-distance migration evolved independently in bats and unique migration behaviors are likely, but because of their cryptic lifestyles, many details remain unknown. North American hoary bats (Lasiurus cinereus cinereus) roost in trees year-round and probably migrate farther than any other bats, yet we still lack basic information about their migration patterns and wintering locations or strategies. This information is needed to better understand unprecedented fatality of hoary bats at wind turbines during autumn migration and to determine whether the species could be susceptible to an emerging disease affecting hibernating bats. Our aim was to infer probable seasonal movements of individual hoary bats to better understand their migration and seasonal distribution in North America. We analyzed the stable isotope values of non-exchangeable hydrogen in the keratin of bat hair and combined isotopic results with prior distributional information to derive relative probability density surfaces for the geographic origins of individuals. We then mapped probable directions and distances of seasonal movement. Results indicate that hoary bats summer across broad areas. In addition to assumed latitudinal migration, we uncovered evidence of longitudinal movement by hoary bats from inland summering grounds to coastal regions during autumn and winter. Coastal regions with nonfreezing temperatures may be important wintering areas for hoary bats. Hoary bats migrating through any particular area, such as a wind turbine facility in autumn, are likely to have originated from a broad expanse of summering grounds from which they have traveled in no recognizable order. Better characterizing migration patterns and wintering behaviors of hoary bats sheds light on the evolution of migration and provides context for conserving these migrants.

Publication Title: 

Mercury in gray wolves (Canis lupus) in Alaska: Increased exposure through consumption of marine prey

Authors: 
McGrew, A.K., L.R. Ballweber, S.K. Moses, C.A. Stricker, K.B. Beckmen, M.D. Salman, and T.M. O’Hara
Publication Date: 
2014
Updated Date (text): 
2013-11-29
Parent Publication Title: 
Science of the Total Environment
Publication Type: 
Archive number: 
2014/0002 FORT
Species: 

Pub Abstract: 
Publication Title: 

Using riparian spiders as sentinels of ecosystem exposure and recovery at contaminated sediment sites

Authors: 
Walters, D.M. and M.A. Mills
Publication Date: 
2013
Updated Date (text): 
2013-06-17
Parent Publication Title: 
Society of Environmental Toxicology and Chemistry, North America Annual Meeting, Nov. 17-21, 2013, Nashville, TN
Publication Type: 
Archive number: 
2013/0090 FORT

Pub Abstract: 
Publication Title: 

Variation in hair d13C and d15N values in long-tailed macaques (Macaca fascicularis) from Singapore

Authors: 
Schillaci, M.A., J.M. Castellini, C.A. Stricker, L. Jones-Engel, B.P.Y.-H. Lee, and T.M. O'Hara
Updated Date (text): 
2013-06-03
Parent Publication Title: 
Journal of Primate Conservation
Publication Type: 
Archive number: 

Pub Abstract: 

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