scholarly journals Intra-hair stable isotope analysis implies seasonal shift to salmon in gray wolf diet

2002 ◽  
Vol 80 (9) ◽  
pp. 1638-1642 ◽  
Author(s):  
C T Darimont ◽  
T E Reimchen
Keyword(s):  
Stable Isotope ◽  
Isotope Analysis ◽  
Niche Differentiation ◽  
Caloric Content ◽  
Gray Wolf ◽  
Large Mammals ◽  
Dietary Shift ◽  
Gray Wolves ◽  
Seasonal Shift ◽  
Stable Isotope Signatures

Seasonal shifts in diet are widespread, but our ability to detect them can be limited. Comparisons of stable isotope signatures in metabolically inert tissue portions grown at different times are inadequately exploited in dietary reconstructions. We propose that segments of guard hair can index diet to periods of growth (i.e., seasons differing in resource availability). We examined inter-hair δ13C and δ15N signatures from gray wolves (Canis lupus) of British Columbia to test whether the bulk of enriched (marine-derived) nutrients was assimilated during fall, the peak of salmon (Onchorynchus spp.) migration. In five animals, we detected a seasonal dietary shift: relatively more 13C and 15N was assimilated during fall than during summer, suggesting use of salmon during fall. Twelve wolves and both controls showed no seasonal shift in diet. Using salmon when available may be adaptive, given its predictability, spatial constraint, caloric content, and lower potential to inflict injury relative to that imposed by large mammals. Our study complements others that also used novel and fine-scale isotope approaches and may permit the identification of otherwise undetectable niche differentiation among conspecifics or heterospecifics.

scholarly journals Temporal dietary shift in jellyfish revealed by stable isotope analysis

2016 ◽  
Vol 163 (5) ◽  
Author(s):  
Jamileh Javidpour ◽  
Ashlie N. Cipriano-Maack ◽  
Agnes Mittermayr ◽  
Jan Dierking
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Dietary Shift

scholarly journals Developing Non-destructive Methods to Determine Natal Origins of Snake River Cutthroat Trout in the Jackson Lake Watershed

2013 ◽  
Vol 36 ◽  
pp. 112-122
Author(s):  
Scott Carleton
Keyword(s):  
Stable Isotope ◽  
Native Species ◽  
Isotope Analysis ◽  
Cutthroat Trout ◽  
Snake River ◽  
Early Life Stages ◽  
Data Resource ◽  
Resource Managers ◽  
Stable Isotope Signatures ◽  
Non Destructive

Across their native ranges, cutthroat trout populations are imperiled due to habitat loss, habitat alteration, and introduction of non-native species (Liknes and Graham 1988, Behnke 1992, Hitt et al. 2003). These changes have not gone undetected and a great deal of time and money have been invested in conservation and restoration of cutthroat trout populations (Kershner 1995, USDA 1996, Young and Harig 2002, Baker et al. 2008). The success of these projects is tightly linked to the ability of resource managers to prioritize management efforts. Specifically, where should the investments of time and money br focused to yield the greatest impact on conservation and restoration. This study proposes to use a relatively new, proven analytical tool, stable isotope analysis, to identify differences in the stable isotope signatures of tributary streams entering Jackson Lake. These differences are translated into the tissues, specifically otolith bones, of cutthroat trout that use these tributaries during early life stages or upon return for spawning (Kennedy et al. 2002, Muhlfeld et al. 2005, Coghlan et al. 2007, Barnett-Johnson et al. 2008, Walther et al. 2008, Ziegler and Whitledge 2010). The ability to link adult trout back to their natal origins and identify where these adults are returning to spawn will provide the data resource managers need to prioritize conservation and restoration efforts in the upper Snake River watershed, with special emphasis on tributary streams entering Jackson Lake.

scholarly journals Technical note: comparison of water vapor sampling techniques for stable isotope analysis

2019 ◽  
Author(s):  
César Dionisio Jiménez-Rodríguez ◽  
Miriam Coenders-Gerrits ◽  
Thom Bogaard ◽  
Erika Vatiero ◽  
Hubert Savenije
Keyword(s):  
Water Vapor ◽  
Stable Isotope ◽  
Isotope Analysis ◽  
Isotopic Fractionation ◽  
Technical Note ◽  
Sampling Techniques ◽  
Cavity Output ◽  
Stable Isotope Signatures ◽  
Pumping Rates ◽  
Vapor Sampling

Abstract. Water vapor samples are key elements to describe the evaporation process thanks to the stable isotope signatures of δ2H and δ18O. However, its sampling is a difficult task that can introduce errors due to isotopic fractionation. This study investigates the consistency of different sampling techniques for atmospheric water vapor. The isotope signature of a parcel of air was determined with a cavity output spectroscopy device during a period of 3 hours (benchmark). This parcel of air was sampled simultaneously with 3 types of sampling bags made of different materials (metalized polyethylene -MPE-, polyvinyl fluoride -PVF-, low density polyethylene -LDPE-) and with 2 cryogenic baths running at two different pumping rates (3 L min-1 and 50 mL min-1). The tested water vapor sampling techniques differ in their ability to keep reliable measurements after sampling and are highly susceptible to procedural errors. MPE bags are the best option for measuring samples up to two weeks of storage after sampling. LDPE and PVF bags are only reliable if the measurement is performed on the same sampling day.

Seasonal foraging strategies of Alaskan gray wolves (Canis lupus) in an ecosystem subsidized by Pacific salmon (Oncorhynchus spp.)

2017 ◽  
Vol 95 (8) ◽  
pp. 555-563 ◽  
Author(s):  
Ashley E. Stanek ◽  
Nathan Wolf ◽  
Grant V. Hilderbrand ◽  
Buck Mangipane ◽  
Douglas Causey ◽  
...  
Keyword(s):  
Canis Lupus ◽  
Pacific Salmon ◽  
Social Groups ◽  
Isotope Analysis ◽  
Food Resource ◽  
Foraging Strategies ◽  
Gray Wolf ◽  
Gray Wolves ◽  
Individual Scale ◽  
The Individual

Despite frequent observations of gray wolves (Canis lupus L., 1758) using nonungulate prey, the seasonal and interannual variation in the use and relative importance of alternative prey sources to gray wolf diets have not been studied at the individual scale. We used stable isotope analysis (δ13C and δ15N) of guard hair and blood components (clot and serum) collected over 4 years to examine the occurrence, extent, and temporal variation of Pacific salmon (genus Oncorhynchus Suckley, 1861) as a food resource by both individual wolves and social groups in Lake Clark National Park and Preserve in southwestern Alaska, USA. Our results demonstrate substantial variability in the use of salmon over time. During summer, diets of five wolves consisted of at least 50% salmon, while the diets of 17 wolves consisted of primarily terrestrial prey. Over 3 years, one group of wolves consistently consumed salmon in summer and switched to terrestrial prey in winter. Prey choices were generally similar within social groups; however, the degree to which individuals consumed salmon was highly variable. The use of salmon as exhibited by wolves in Lake Clark is likely widespread where salmon are abundant and this finding should be taken into consideration in the conservation and management of wolves and their prey.

scholarly journals Metabolic Fates of Evening Crop-Stored Sugar in Ruby-Throated Hummingbirds (Archilochus colubris)

Diversity ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 9 ◽  
Author(s):  
Erich Eberts ◽  
Morag Dick ◽  
Kenneth Welch
Keyword(s):  
Stable Isotope ◽  
Isotope Analysis ◽  
Sugar Solution ◽  
Substantial Portion ◽  
Evening Meal ◽  
Floral Nectar ◽  
Stable Isotope Signatures ◽  
Energy Stores ◽  
Energy Maximization ◽  
Evening Hyperphagia

During the day, hummingbirds quickly metabolize floral nectar to fuel high metabolic demands, but are unable to feed at night. Though stored fat is the primary nocturnal metabolic fuel, it has been suggested that hummingbirds store nectar in their crop to offset fat expenditure in the night or to directly fuel their first foraging trip in the morning. We examine the use of crop-stored sugar in the nocturnal energy budget of ruby-throated hummingbirds (Archilochus colubris) using respirometry and 13C stable isotope analysis. Hummingbirds were fed a 13C-enriched sugar solution before lights-out and held in respirometry chambers overnight without food. Respirometry results indicate that the hummingbirds metabolized the sugar in the evening meal in less than 2 h, and subsequently primarily catabolized fat. Breath stable isotope signatures provide the key insight that the hummingbirds converted a substantial portion of an evening meal to fats, which they later catabolized to support their overnight metabolism and spare endogenous energy stores. These results show that the value of a hummingbird’s evening meal depends on how much of this energy was converted to fat. Furthermore, this suggests that evening hyperphagia is an important energy maximization strategy, especially during energetically expensive periods such as migration or incubation.

scholarly journals Coupled micromorphological and stable isotope analysis of Quaternary calcrete development

2015 ◽  
Vol 84 (2) ◽  
pp. 272-286 ◽  
Author(s):  
Kathryn Adamson ◽  
Ian Candy ◽  
Liz Whitfield
Keyword(s):  
Stable Isotope ◽  
Arid Regions ◽  
Isotope Analysis ◽  
Isotopic Analysis ◽  
Proxy Records ◽  
River Terraces ◽  
Stable Isotopic Analysis ◽  
Stable Isotopic ◽  
Stable Isotope Signatures ◽  
Positive Covariance

Pedogenic calcretes are widespread in arid and semi-arid regions. Using calcrete profiles from four river terraces of the Rio Alias in southeast Spain, this study explores the potential of using detailed micromorphological and stable isotopic analysis to more fully understand the impacts of Quaternary environmental change on calcrete development. The four profiles increase in carbonate complexity with progressive age, reflecting calcretisation over multiple glacial–interglacial cycles since MIS 9 (c. 300 ka). Calcrete profiles contain a mixture of Alpha (non-biogenic) and Beta (biogenic) microfabrics. Alpha fabrics have higher δ13C and δ18O values. The profiles contain a range of crystal textures, but there is little difference between the δ13C and δ18O values of spar, microspar, and micrite cements. Strong positive covariance between δ13C and δ18O suggests that both isotopes are responding to the same environmental parameter, which is inferred to be relative aridity. The study reveals that the detailed co-analysis of calcrete micromorphology and stable isotope signatures can allow patterns of calcrete formation to be placed into a wider palaeoclimatic context. This demonstrates the potential of this technique to more reliably constrain the palaeoenvironmental significance of secondary carbonates in dryland settings where other proxy records may be poorly preserved.

scholarly journals Gaining insight into the assimilated diet of small bear populations by stable isotope analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giulio Careddu ◽  
Paolo Ciucci ◽  
Stella Mondovì ◽  
Edoardo Calizza ◽  
Loreto Rossi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Late Summer ◽  
Early Summer ◽  
Vegetable Crops ◽  
Large Mammals ◽  
Fleshy Fruits ◽  
Hair Samples ◽  
Assimilated Diet

AbstractApennine brown bears (Ursus arctos marsicanus) survive in an isolated and critically endangered population, and their food habits have been studied using traditional scat analysis. To complement current dietary knowledge, we applied Stable Isotope Analysis (SIA) to non-invasively collected bear hairs that had been individually recognized through multilocus genotyping. We analysed carbon (δ13C) and nitrogen (δ15N) stable isotopes of hair sections and bear key foods in a Bayesian mixing models framework to reconstruct the assimilated diet on a seasonal basis and to assess gender and management status effects. In total, we analysed 34 different seasonal bear key foods and 35 hair samples belonging to 27 different bears (16 females and 11 males) collected during a population survey in 2014. Most bears showed wide δ15N and δ13C ranges and individual differences in seasonal isotopic patterns. Vegetable matter (herbs, fleshy fruits and hard mast) represented the major component of the assimilated diet across the dietary seasons, whereas vegetable crops were rarely and C4 plants (i.e., corn) never consumed. We confirmed an overall low consumption of large mammals by Apennine bears consistently between sexes, with highest values in spring followed by early summer but null in the other seasons. We also confirmed that consumption of fleshy fruits peaked in late summer, when wild predominated over cultivated fleshy fruits, even though the latter tended to be consumed in higher proportion in autumn. Male bears had higher δ 15N values than females in spring and autumn. Our findings also hint at additional differences in the assimilated diet between sexes, with females likely consuming more herbs during spring, ants during early summer, and hard mast during fall compared to males. In addition, although effect sizes were small and credibility intervals overlapped considerably, management bears on average were 0.9‰ lower in δ 13C and 2.9‰ higher in δ 15N compared to non-management bears, with differences in isotopic values between the two bear categories peaking in autumn. While non-management bears consumed more herbs, wild fleshy fruits, and hard mast, management bears tended to consume higher proportions of cultivated fruits, ants, and large mammals, possibly including livestock. Although multi-year sampling and larger sample sizes are needed to support our findings, our application confirms that SIA can effectively integrate previous knowledge and be efficiently conducted using samples non-invasively collected during population surveys.

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