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Gurney KEB, Classen HL, Clark RG. Testing for effects of growth rate on isotope trophic discrimination factors and evaluating the performance of Bayesian stable isotope mixing models experimentally: A moment of truth? PLoS One 2024; 19:e0304495. [PMID: 38875228 PMCID: PMC11178173 DOI: 10.1371/journal.pone.0304495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/13/2024] [Indexed: 06/16/2024] Open
Abstract
Discerning assimilated diets of wild animals using stable isotopes is well established where potential dietary items in food webs are isotopically distinct. With the advent of mixing models, and Bayesian extensions of such models (Bayesian Stable Isotope Mixing Models, BSIMMs), statistical techniques available for these efforts have been rapidly increasing. The accuracy with which BSIMMs quantify diet, however, depends on several factors including uncertainty in tissue discrimination factors (TDFs; Δ) and identification of appropriate error structures. Whereas performance of BSIMMs has mostly been evaluated with simulations, here we test the efficacy of BSIMMs by raising domestic broiler chicks (Gallus gallus domesticus) on four isotopically distinct diets under controlled environmental conditions, ideal for evaluating factors that affect TDFs and testing how BSIMMs allocate individual birds to diets that vary in isotopic similarity. For both liver and feather tissues, δ13C and δ 15N values differed among dietary groups. Δ13C of liver, but not feather, was negatively related to the rate at which individuals gained body mass. For Δ15N, we identified effects of dietary group, sex, and tissue type, as well as an interaction between sex and tissue type, with females having higher liver Δ15N relative to males. For both tissues, BSIMMs allocated most chicks to correct dietary groups, especially for models using combined TDFs rather than diet-specific TDFs, and those applying a multiplicative error structure. These findings provide new information on how biological processes affect TDFs and confirm that adequately accounting for variability in consumer isotopes is necessary to optimize performance of BSIMMs. Moreover, results demonstrate experimentally that these models reliably characterize consumed diets when appropriately parameterized.
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Affiliation(s)
- Kirsty E B Gurney
- Science and Technology Branch, Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
| | - Henry L Classen
- College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Robert G Clark
- Science and Technology Branch, Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
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2
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Robinson AL, Elliott Smith EA, Besser AC, Newsome SD. Tissue-specific carbon isotope patterns of amino acids in southern sea otters. Oecologia 2024; 204:13-24. [PMID: 38227253 DOI: 10.1007/s00442-023-05505-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 12/13/2023] [Indexed: 01/17/2024]
Abstract
The measurement of stable isotope values of individual compounds, such as amino acids (AAs), has become a powerful tool in animal ecology and ecophysiology. As with any emerging technique, questions remain regarding the capabilities and limitations of this approach, including how metabolism and tissue synthesis impact the isotopic values of individual AAs and subsequent multivariate patterns. We measured carbon isotope (δ13C) values of essential (AAESS) and nonessential (AANESS) AAs in bone collagen, whisker, muscle, and liver from ten southern sea otters (Enhydra lutris nereis) that stranded in Monterey Bay, California. Sea otters in this population exhibit high degrees of individual dietary specialization, making this an excellent dataset to explore differences in AA δ13C values among tissues in a wild population. We found the δ13C values of the AANESS glutamic acid, proline, serine, and glycine and the AAESS threonine differed significantly among tissues, indicating possible isotopic discrimination during tissue synthesis. Threonine δ13C values were higher in liver relative to bone collagen and muscle, which may indicate catabolism of threonine for gluconeogenesis, an interpretation further supported by correlations between the δ13C values of threonine and its gluconeogenic products glycine and serine in liver. This intraindividual isotopic variation yielded different ecological interpretations among tissues; for 6/10 of the sea otter individuals analyzed, at least one tissue indicated reliance on a different primary producer source than the other tissues. Our results highlight the importance of gluconeogenesis in a carnivorous marine mammal and indicate that metabolic processes influence AAESS and AANESS δ13C values and multivariate AA δ13C patterns.
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Affiliation(s)
- Alana L Robinson
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA.
| | - Emma A Elliott Smith
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
| | - Alexi C Besser
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
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3
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McCue MD. CO 2 scrubbing, zero gases, Keeling plots, and a mathematical approach to ameliorate the deleterious effects of ambient CO 2 during 13 C breath testing in humans and animals. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9639. [PMID: 37817343 DOI: 10.1002/rcm.9639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/17/2023] [Accepted: 08/26/2023] [Indexed: 10/12/2023]
Abstract
13 C breath testing is increasingly used in physiology and ecology research because of what it reveals about the different fuels that animals oxidize to meet their energetic demands. Here I review the practice of 13 C breath testing in humans and other animals and describe the impact that contamination by ambient/background CO2 in the air can have on the accuracy of 13 C breath measurements. I briefly discuss physical methods to avoid sample contamination as well as the Keeling plot approach that researchers have been using for the past two decades to estimate δ13 C from breath samples mixed with ambient CO2 . Unfortunately, Keeling plots are not suited for 13 C breath testing in common situations where (1) a subject's VCO2 is dynamic, (2) ambient [CO2 ] may change, (3) a subject is sensitive to hypercapnia, or (4) in any flow-through indirect calorimetry system. As such, I present a mathematical solution that addresses these issues by using information about the instantaneous [CO2 ] and the δ13 CO2 of ambient air as well as the diluted breath sample to back-calculate the δ13 CO2 in the CO2 exhaled by the animal. I validate this approach by titrating a sample of 13 C-enriched gas into an air stream and demonstrate its ability to provide accurate values across a wide range of breath and air mixtures. This approach allows researchers to instantaneously calculate the δ13 C of exhaled gas of humans or other animals in real time without having to scrub ambient CO2 or rely on estimated values.
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4
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Pereira AC, Nardoto GB, Colli GR. Sources of intraspecific variation in the isotopic niche of a semi-aquatic predator in a human-modified landscape. PeerJ 2023; 11:e15915. [PMID: 37663285 PMCID: PMC10474837 DOI: 10.7717/peerj.15915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 07/26/2023] [Indexed: 09/05/2023] Open
Abstract
Intraspecific variation modulates patterns of resource use by species, potentially affecting the structure and stability of food webs. In human-modified landscapes, habitat disturbance modifies trophic interactions and intraspecific niche variation, impacting population persistence. Here, we investigated the relationship of sex, ontogeny, and habitat factors with the trophic niche of Caiman crocodilus in an agricultural landscape. We evaluated temporal variation in the trophic niche parameters using carbon and nitrogen stable isotope analysis from different body tissues. We found that caimans exploit the same carbon and nitrogen pools through time, with low isotopic variability between seasons, partly due to the slow isotope turnover rates of tissues in crocodilians. Conversely, the trophic niche of caimans varied across habitats, but with no evidence of a difference between natural and anthropogenic habitats. It apparently results from the influence of habitat suitability, connectivity, and caiman movements during the foraging. Our findings highlight the broader niches of juvenile caimans relative to adults, possibly in response of territorialism and opportunistic foraging strategy. Although using similar resources, females had a larger niche than males, probably associated with foraging strategies during nesting. Considering the sex and body size categories, caimans occupied distinct isotopic regions in some habitats, indicating apparent niche segregation. Ontogenetic trophic shifts in the isotopes (δ13C and δ15N) depended on sex, leading to resource partitioning that can potentially reduce intraspecific competition. Decision-makers and stakeholders should consider the trophic dynamics of sex and body size groups for the sustainable management and conservation of caiman populations, which implies in the maintenance of wetland habitats and landscape heterogeneity in the Formoso River floodplain.
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Affiliation(s)
- André Costa Pereira
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
- Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
| | - Gabriela Bielefeld Nardoto
- Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
| | - Guarino Rinaldi Colli
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
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5
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Tarifa-Mateo N, Saña M, Clop X, Rosell-Melé A, Camalich-Massieu MD, Martín-Socas D. Investigating livestock management in the early Neolithic archaeological site of Cabecicos Negros (Almería, Spain) from the organic residue analysis in pottery. Sci Rep 2023; 13:4797. [PMID: 36959349 PMCID: PMC10036527 DOI: 10.1038/s41598-023-31036-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 03/06/2023] [Indexed: 03/25/2023] Open
Abstract
This paper seeks to reconstruct the management of food resources in the early Neolithic site of Cabecicos Negros in southeastern Spain. For this purpose, we have studied 29 potsherds from Cabecicos Negros (Andalusia, Spain). Applying the methods of gas chromatography and mass spectrometry we were able to recompose the daily use of the sherds related to the consumption and storage of food products. Among the results obtained in this work, we were able to show new evidence of the exploitation of dairy products in the south of the Iberian Peninsula, as well as provide information on the exploitation and management of the early domestic animals herds. To improve the archaeological results obtained, isotopic results were compared with a modern reference of 53 fat samples from the adipose tissue of domestic pigs and wild boars.
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Affiliation(s)
- N Tarifa-Mateo
- Department of Prehistory, Autonomous University of Barcelona, 08193, Bellaterra, Spain.
| | - M Saña
- Department of Prehistory, Autonomous University of Barcelona, 08193, Bellaterra, Spain
| | - X Clop
- Department of Prehistory, Autonomous University of Barcelona, 08193, Bellaterra, Spain
| | - A Rosell-Melé
- Institute of Environmental Science and Technology (ICTA-UAB), Autonomous University of Barcelona, 08193, Bellaterra, Catalonia, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Catalonia, Spain
| | - M D Camalich-Massieu
- Department of Geography and History, Prehistory Area, University of La Laguna, 38200, San Cristóbal de La Laguna, Spain
| | - D Martín-Socas
- Department of Geography and History, Prehistory Area, University of La Laguna, 38200, San Cristóbal de La Laguna, Spain
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6
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Johnson DL, Henderson MT, Franke A, Swan GJF, McDonald RA, Anderson DL, Booms TL, Williams CT. TDF CAM: A method for estimating stable isotope trophic discrimination in wild populations. Ecol Evol 2023; 13:e9709. [PMID: 36620422 PMCID: PMC9817186 DOI: 10.1002/ece3.9709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/14/2022] [Accepted: 12/16/2022] [Indexed: 01/09/2023] Open
Abstract
Stable isotope mixing models (SIMMs) are widely used for characterizing wild animal diets. Such models rely upon using accurate trophic discrimination factors (TDFs) to account for the digestion, incorporation, and assimilation of food. Existing methods to calculate TDFs rely on controlled feeding trials that are time-consuming, often impractical for the study taxon, and may not reflect natural variability of TDFs present in wild populations.We present TDFCAM as an alternative approach to estimating TDFs in wild populations, by using high-precision diet estimates from a secondary methodological source-in this case nest cameras-in lieu of controlled feeding trials, and provide a framework for how and when it should be applied.In this study, we evaluate the TDFCAM approach in three datasets gathered on wild raptor nestlings (gyrfalcons Falco rusticolus; peregrine falcons Falco perigrinus; common buzzards Buteo buteo) comprising contemporaneous δ13C & δ15N stable isotope data and high-quality nest camera dietary data. We formulate Bayesian SIMMs (BSIMMs) incorporating TDFs from TDFCAM and analyze their agreement with nest camera data, comparing model performance with those based on other relevant TDFs. Additionally, we perform sensitivity analyses to characterize TDFCAM variability, and identify ecological and physiological factors contributing to that variability in wild populations.Across species and tissue types, BSIMMs incorporating a TDFCAM outperformed any other TDF tested, producing reliable population-level estimates of diet composition. We demonstrate that applying this approach even with a relatively low sample size (n < 10 individuals) produced more accurate estimates of trophic discrimination than a controlled feeding study conducted on the same species. Between-individual variability in TDFCAM estimates for ∆13C & ∆15 N increased with analytical imprecision in the source dietary data (nest cameras) but was also explained by natural variables in the study population (e.g., nestling nutritional/growth status and dietary composition).TDFCAM is an effective method of estimating trophic discrimination in wild animal populations. Here, we use nest cameras as source dietary data, but this approach is applicable to any high-accuracy method of measuring diet, so long as diet can be monitored over an interval contemporaneous with a tissue's isotopic turnover rate.
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Affiliation(s)
- Devin L. Johnson
- Department of Biology and WildlifeUniversity of Alaska FairbanksFairbanksAlaskaUSA
| | | | | | - George J. F. Swan
- Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos NaturalesUniversidad Austral de ChileValdiviaChile
| | | | | | | | - Cory T. Williams
- Department of BiologyColorado State UniversityFort CollinsColoradoUSA
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7
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McCall A, Gamarra B, Carlson KSD, Bernert Z, Cséki A, Csengeri P, Domboróczki L, Endrődi A, Hellebrandt M, Horváth A, Király Á, Kiss K, Koós J, Kovács P, Köhler K, Szolnoki L, Zoffmann ZK, Sirak K, Szeniczey T, Dani J, Hajdu T, Pinhasi R. Stable carbon and nitrogen isotopes identify nuanced dietary changes from the Bronze and Iron Ages on the Great Hungarian Plain. Sci Rep 2022; 12:16982. [PMID: 36217009 PMCID: PMC9550812 DOI: 10.1038/s41598-022-21138-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/22/2022] [Indexed: 12/29/2022] Open
Abstract
The Great Hungarian Plain (GHP) served as a geographic funnel for population mobility throughout prehistory. Genomic and isotopic research demonstrates non-linear genetic turnover and technological shifts between the Copper and Iron Ages of the GHP, which influenced the dietary strategies of numerous cultures that intermixed and overlapped through time. Given the complexities of these prehistoric cultural and demographic processes, this study aims to identify and elucidate diachronic and culture-specific dietary signatures. We report on stable carbon and nitrogen isotope ratios from 74 individuals from nineteen sites in the GHP dating to a ~ 3000-year time span between the Early Bronze and Early Iron Ages. The samples broadly indicate a terrestrial C3 diet with nuanced differences amongst populations and through time, suggesting exogenous influences that manifested in subsistence strategies. Slightly elevated δ15N values for Bronze Age samples imply higher reliance on protein than in the Iron Age. Interestingly, the Füzesabony have carbon values typical of C4 vegetation indicating millet consumption, or that of a grain with comparable δ13C ratios, which corroborates evidence from outside the GHP for its early cultivation during the Middle Bronze Age. Finally, our results also suggest locally diverse subsistence economies for GHP Scythians.
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Affiliation(s)
| | - Beatriz Gamarra
- grid.452421.4Institut Català de Paleoecologia Humana i Evolució Social (IPHES), Zona Educacional 4, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain ,grid.410367.70000 0001 2284 9230Departament d’Història i Història de l’Art, Universitat Rovira i Virgili, Avinguda de Catalunya 35, 43002 Tarragona, Spain
| | - Kellie Sara Duffett Carlson
- grid.10420.370000 0001 2286 1424Department of Evolutionary Anthropology, University of Vienna, 1030 Vienna, Austria ,grid.10420.370000 0001 2286 1424Human Evolution and Archaeological Sciences, University of Vienna, 1030 Vienna, Austria
| | - Zsolt Bernert
- grid.424755.50000 0001 1498 9209Department of Anthropology, Hungarian Natural History Museum, Ludovika tér 1-3, 1083 Budapest, Hungary
| | | | - Piroska Csengeri
- Department of Archaeology, Herman Ottó Museum, Görgey Artúr u. 28, 3529 Miskolc, Hungary
| | - László Domboróczki
- Department of Archaeology, Dobó István Castle Museum, Vár 1, Eger, 3300 Hungary
| | - Anna Endrődi
- grid.452168.c0000 0001 0943 6204Department of Prehistoric and Migration Period, Budapest History Museum, Aquincum Museum and Archaeological Park, Szentendrei út 135, 1031 Budapest, Hungary
| | - Magdolna Hellebrandt
- Department of Archaeology, Herman Ottó Museum, Görgey Artúr u. 28, 3529 Miskolc, Hungary
| | - Antónia Horváth
- Department of Archaeology, Herman Ottó Museum, Görgey Artúr u. 28, 3529 Miskolc, Hungary
| | - Ágnes Király
- grid.5018.c0000 0001 2149 4407Institute of Archaeology, Research Centre for Humanities, Hungarian Academy of Sciences, Tóth Kálmán utca 4, 1097 Budapest, Hungary
| | - Krisztián Kiss
- grid.424755.50000 0001 1498 9209Department of Anthropology, Hungarian Natural History Museum, Ludovika tér 1-3, 1083 Budapest, Hungary ,grid.5591.80000 0001 2294 6276Department of Biological Anthropology, Institute of Biology, Faculty of Science, Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117 Budapest, Hungary
| | - Judit Koós
- Department of Archaeology, Herman Ottó Museum, Görgey Artúr u. 28, 3529 Miskolc, Hungary
| | - Péter Kovács
- Damjanich János Museum, Kossuth tér 4, 5000 Szolnok, Hungary
| | - Kitti Köhler
- grid.5018.c0000 0001 2149 4407Institute of Archaeology, Research Centre for Humanities, Hungarian Academy of Sciences, Tóth Kálmán utca 4, 1097 Budapest, Hungary
| | | | - Zsuzsanna K. Zoffmann
- grid.452093.90000 0001 1957 0247Department of Anthropology, Hungarian National Museum, Múzeum krt. 14-16, Budapest, 1083 Hungary
| | - Kendra Sirak
- grid.38142.3c000000041936754XDepartment of Genetics, Harvard Medical School, Boston, MA 02115 USA ,grid.38142.3c000000041936754XDepartment of Human Evolutionary Biology, Harvard University, Cambridge, MA USA
| | - Tamás Szeniczey
- grid.5591.80000 0001 2294 6276Department of Biological Anthropology, Institute of Biology, Faculty of Science, Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117 Budapest, Hungary
| | - János Dani
- Déri Museum, Déri tér 1, 4026 Debrecen, Hungary
| | - Tamás Hajdu
- grid.5591.80000 0001 2294 6276Department of Biological Anthropology, Institute of Biology, Faculty of Science, Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117 Budapest, Hungary
| | - Ron Pinhasi
- grid.10420.370000 0001 2286 1424Department of Evolutionary Anthropology, University of Vienna, 1030 Vienna, Austria ,grid.10420.370000 0001 2286 1424Human Evolution and Archaeological Sciences, University of Vienna, 1030 Vienna, Austria
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Shev GT, Laffoon JE. Paleodietary reconstruction of endemic rodents from the precolumbian Dominican Republic: Discriminating wild feeding behavior from diets linked to human niche construction activities. INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY 2022; 32:976-995. [PMID: 36618439 PMCID: PMC9804766 DOI: 10.1002/oa.3149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/14/2022] [Accepted: 07/27/2022] [Indexed: 06/17/2023]
Abstract
In the Greater Antilles, certain animal taxa that have long been theorized to have been managed by indigenous peoples prior to AD1492, the main candidates being a group of endemic caviomorph rodents known as hutias (Capromyinae). This isotopic study investigates the paleodiets of several species of endemic rodents from three late precolonial sites in the northern Dominican Republic: El Flaco (cal. ad 990-1452), El Carril (cal. ad 1030-1262), and La Entrada (cal. ad 840-900) to assess whether human influence over animal diets can be determined. We examined bone collagen carbon (δ13Cco) and nitrogen (δ15N) and tooth enamel carbon (δ13Cen) isotope values of three species of hutias, Isolobodon portoricensis, Isolobodon montanus, and Plagiodontia aedium, alongside edible rat (Brotomys sp.), and domestic guinea pig (Cavia porcellus). To estimate dietary source contributions, we employed a Bayesian dietary mixing model (FRUITS v.3.0) and ran three different permutations to assess the relative contributions of C3 or C4/CAM plants. The addition of an extra 79 wild C3 and 40 wild C4/CAM plant species' isotope values from published sources to an established isotopic foodweb for the Caribbean region enabled us to discriminate between wild and domestic C3 and C4/CAM plant food sources in two of these models. Our results provide evidence of the significant consumption of domestic C4/CAM plants by some animals. This likely represents maize (Zea mays) consumption, which is known to have been ubiquitously cultivated by indigenous peoples in the region. This is particularly the case for I. portoricensis, as FRUITS modeling suggests that a few individuals consumed C4/CAM plants well beyond their expected natural diets as determined from feeding studies of extant hutia species. This may indicate human influence over endemic rodent diets due to niche construction activities such as horticultural practices and may reflect either opportunistic feeding on human produce or the purposeful supplementation of hutia diets by humans.
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Affiliation(s)
- Gene T. Shev
- Faculty of ArchaeologyLeiden UniversityLeidenThe Netherlands
| | - Jason E. Laffoon
- Faculty of ArchaeologyLeiden UniversityLeidenThe Netherlands
- Geology & Geochemistry ClusterVrije Universiteit AmsterdamAmsterdamThe Netherlands
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9
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Jimbo M, Ishinazaka T, Shirane Y, Umemura Y, Yamanaka M, Uno H, Sashika M, Tsubota T, Shimozuru M. Diet selection and asocial learning: Natal habitat influence on lifelong foraging strategies in solitary large mammals. Ecosphere 2022. [DOI: 10.1002/ecs2.4105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Mina Jimbo
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | | | - Yuri Shirane
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
- Hokkaido Research Organization Sapporo Japan
| | | | | | - Hiroyuki Uno
- Faculty of Agriculture Tokyo University of Agriculture and Technology Tokyo Japan
| | - Mariko Sashika
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | - Toshio Tsubota
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
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10
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Chibowski P, Brzeziński M, Suska-Malawska M, Zub K. Diet/Hair and Diet/Faeces Trophic Discrimination Factors for Stable Carbon and Nitrogen Isotopes, and Hair Regrowth in the Yellow-Necked Mouse and Bank Vole. ANN ZOOL FENN 2022. [DOI: 10.5735/086.059.0115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Piotr Chibowski
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Marcin Brzeziński
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Małgorzata Suska-Malawska
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Karol Zub
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, PL-17-230 Białowieża, Poland
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11
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He M, Liu F, Wang F. Determination of the stable isotope discrimination factor of wild organisms: a case study of the red swamp crayfish in integrated rice-crayfish ( Procambarus clarkii) culture without artificial diets. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2022; 58:81-98. [PMID: 34890270 DOI: 10.1080/10256016.2021.2008380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
This study collected samples from a 95-day integrated rice-crayfish culture experiment, and determined the stable isotope discrimination factor of the red swamp crayfish (Procambarus clarkii) by using a model method and difference value method. The isotope ratios of P. clarkii and the dietary resources in rice fields and its feeding niche volumes were 'conservative' as proposed. This result broadly supported the assumption of the laboratory feeding experiment that animals should be fed a single diet exhibiting a constant isotopic composition. Using standard ellipse areas (SEA) to screen the data, growth- and time-dependent models of carbon and nitrogen isotopes of females and males were obtained. The Δ13C and its half-lives for females and males were 0.67 (21.0 d) and 0.91 (33.0 d), whereas Δ15N and its half-lives for those were 3.45 (17.8 d) and 3.05 (17.3 d), respectively. The results of integrated rice-crayfish culture without artificial diets provides a reference example for future studies on species-specific discrimination factors in specific field habitats.
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Affiliation(s)
- Mingdi He
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Jimo, People's Republic of China
| | - Feng Liu
- Shandong Freshwater Fisheries Research Institute, Jinan, People's Republic of China
| | - Fang Wang
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Jimo, People's Republic of China
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12
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Javornik J, Šturm MB, Jerina K. Four approaches for estimating isotope discrimination factors produce contrasting dietary estimates for bears. URSUS 2021. [DOI: 10.2192/ursus-d-19-00028.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jernej Javornik
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
| | - Martina Burnik Šturm
- University of Natural Resources and Life Sciences (BOKU), Institute of Analytical Chemistry, Mutgasse 18, 1190 Vienna, Austria
| | - Klemen Jerina
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
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Woodborne S, Botha H, Huchzermeyer D, Myburgh J, Hall G, Myburgh A. Ontogenetic dependence of Nile crocodile (Crocodylus niloticus) isotope diet-to-tissue discrimination factors. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9159. [PMID: 34224610 DOI: 10.1002/rcm.9159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE The diet of wild Nile crocodiles (Crocodylus niloticus) is difficult to assess because they are cryptic and nocturnal predators that are extremely sensitive to disturbance by observers, and stomach content analysis is challenging, especially in large specimens. Stable light isotope analysis provides a means of assessing their diet, but diet-to-tissue discrimination factors have yet to be established for the species. METHODS Isotope ratio (15 N/14 N and 13 C/12 C expressed as δ15 N and δ13 C) analyses of scutes, claws, and blood of farmed crocodiles of different sizes were compared with the isotope values of their lifelong diet, which comprises chickens from a single supplier. RESULTS Systematic size dependence in the diet-to-tissue discrimination factors for scute collagen, scute keratin, and claw keratin is described in regression relationships against the snout to vent length. Fixed values are presented for erythrocytes and blood plasma because blood was not sampled from juveniles. CONCLUSIONS The diet-to-tissue discrimination factors help assess the diet of wild crocodiles. The diet of crocodiles from Lake Flag Boshielo shows a clear ontogenic shift, as has been seen in other studies, and the results strongly indicate a dependence on the terrestrial food web rather than a fish diet. That this population may exploit a terrestrial diet highlights potential conflicts for conserving Nile crocodiles outside protected areas.
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Affiliation(s)
- Stephan Woodborne
- Tandem & AMS Laboratory, iThemba LABS, Johannesburg, South Africa
- Stable Isotope Laboratory, Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Hannes Botha
- Mpumalanga Tourism and Parks Agency, Scientific Services, Nelspruit, South Africa
- Department of Biodiversity, University of Limpopo, Sovenga, South Africa
| | | | - Jan Myburgh
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Grant Hall
- Stable Isotope Laboratory, Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Albert Myburgh
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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Pedrosa F, Bercê W, Costa VE, Levi T, Galetti M. Diet of invasive wild pigs in a landscape dominated by sugar cane plantations. J Mammal 2021. [DOI: 10.1093/jmammal/gyab100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Abstract
Understanding the mechanisms by which alien species become invasive can assure successful control programs and mitigate alien species’ impacts. The distribution of invasive wild pigs (Sus scrofa) has been sharply expanding throughout all regions of Brazil in the last few years. Here we demonstrate that large monocultural plantations provide the primary resource subsidies to invasive wild pigs in Brazil. We analyzed 106 stomach contents and carbon stable isotopes (δ13C) of 50 hair samples of wild pigs from a population immersed in a landscape dominated by sugar cane agriculture. Stomach contents were dominated by corn (41%), sugarcane (28.5%), vegetal matter (all other vegetation besides crops, 27%), and animal matter (vertebrates and invertebrates, 4%). Bayesian mixing model analysis of δ13C showed that food sources from C4 photosynthetic pathway (represented by corn and sugarcane) accounted for 94% of the long-term diet, while C3 food sources for only 6.2%. Our results indicate that corn and sugar cane are subsidizing the diet of wild pigs and can facilitate the population growth of this invasive species. Given that Brazil is a major agricultural producer and a hotspot of biodiversity, it is extremely concerning that extensive agriculture may accelerate the expansion of this invasive species, resulting in economic losses and cascading effects on natural habitats.
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Affiliation(s)
- Felipe Pedrosa
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Rio Claro, SP, Brazil
- Mão na Mata – Manejo e Soluções Ambientais, São Paulo, SP, Brazil
| | - William Bercê
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Rio Claro, SP, Brazil
| | - Vladimir Eliodoro Costa
- Centro de Isótopos Estáveis, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Taal Levi
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
| | - Mauro Galetti
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Rio Claro, SP, Brazil
- Department of Biology, University of Miami, Coral Gables, FL, USA
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15
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Warne RW, Wolf BO. Nitrogen stable isotope turnover and discrimination in lizards. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9030. [PMID: 33332668 DOI: 10.1002/rcm.9030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
RATIONALE Nitrogen stable isotope ratio (δ15 N) processes are not well described in reptiles, which limits reliable inference of trophic and nutrient dynamics. In this study we detailed δ15 N turnover and discrimination (Δ15 N) in diverse tissues of two lizard species, and compared these results with previously published carbon data (δ13 C) to inform estimates of reptilian foraging ecology and nutrient physiology. METHODS We quantified 15 N incorporation and discrimination dynamics over 360 days in blood fractions, skin, muscle, and liver of Sceloporus undulatus and Crotaphytus collaris that differed in body mass. Tissue samples were analyzed on a continuous flow isotope ratio mass spectrometer. RESULTS Δ15 N for plasma and red blood cells (RBCs) ranged between +2.7 and +3.5‰; however, skin, muscle, and liver did not equilibrate, hindering estimates for these somatic tissues. 15 N turnover in plasma and RBCs ranged from 20.7 ± 4 to 303 ± 166 days among both species. Comparison with previously published δ13 C results for these same samples showed that 15 N and 13 C incorporation patterns were uncoupled, especially during winter when hibernation physiology could have played a role. CONCLUSIONS Our results provide estimates of 15 N turnover rates and discrimination values that are essential to using and interpreting isotopes in studies of diet reconstruction, nutrient allocation, and trophic characterization in reptiles. These results also suggest that somatic tissues can be unreliable, while life history shifts in nutrient routing and metabolism potentially cause 15 N and 13 C dynamics to be decoupled.
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Affiliation(s)
- Robin W Warne
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Blair O Wolf
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
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16
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Hopkins JB, Ferguson JM, Frederick C, Jerina K. Measuring the impact of corn on mammalian omnivores. J Mammal 2021. [DOI: 10.1093/jmammal/gyaa152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
In human-dominated landscapes throughout the world, wildlife seek out anthropogenic foods because they are high in nutritional value and are consistently available. To investigate this mode of foraging, some researchers use stable isotope analysis to detect these animals in populations and estimate their individual diets. In this study, we develop an integrative approach to measure the proportion of corn, a C4 plant, in the diets of free-ranging mammalian omnivores in C3-dominated ecosystems. We fed captive mice corn, C3 plants, and meat until carbon stable isotopes (δ 13C) from each diet equilibrated in their hair. We then used carbon discrimination factors (Δ 13C; offsets between stable isotope values of consumer tissues and their foods) for mice from these feeding trials and a simple carbon stable isotope mixing model to estimate the corn-based diets of free-ranging American black bears in Wisconsin and brown bears in Slovenia. We used Δ 13C factors for mice to estimate the diets of bears because mouse models are used commonly to study mammalian diet and health, including humans and bears, and body mass has no effect on carbon discrimination factors in monogastric mammalian omnivores. In this study, we found that mice grew fastest, largest, and δ 13C values equilibrated quickest in the hair of mice fed meat versus plant-based diets, suggesting protein quantity (quality was the same) has an effect on Δ 13C. Evidence also suggests that Δ 13C did not increase with animal growth rate as all mice grew throughout the 109-day feeding trials, but isotopic equilibration occurred early while mice still were subadults and was maintained throughout their adult lives. We also found that Δ 13C was highest and most variable in the hair, serum, and liver, of mice fed a mixed diet of C3 plants, supporting our mixed diet hypothesis that states that Δ 13C varies more among tissues of animals fed mixed diets than animals fed nonmixed diets because the former are composed of multiple foods, each with different macromolecular and isotopic compositions. Lastly, we found that corn may have been a more important component of bear diets in Wisconsin than previously thought (adults: x¯ = 29%; x¯ = 33%; subadults: x¯ = 22%; x¯ = 28%), and male brown bears may have fed on 50% more corn (x¯ = 47% versus 31%) in autumn during a year when beechnut availability was low. In a world that is rapidly changing, it is more important than ever to develop the appropriate quantitative tools to measure the impact people have on wildlife. Here, we provide such a tool for monogastric mammalian omnivores and encourage other researchers to do the same for other taxa of interest.
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Affiliation(s)
- John B Hopkins
- Center for Wildlife Studies, North Yarmouth, ME, USA
- University of Ljubljana, Biotechnical Faculty, Department of Forestry and Renewable Forest Resources, Večna pot 83, 1000 Ljubljana, Slovenia
| | - Jake M Ferguson
- School of Life Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | | | - Klemen Jerina
- University of Ljubljana, Biotechnical Faculty, Department of Forestry and Renewable Forest Resources, Večna pot 83, 1000 Ljubljana, Slovenia
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Lavrinienko A, Tukalenko E, Kesäniemi J, Kivisaari K, Masiuk S, Boratyński Z, Mousseau TA, Milinevsky G, Mappes T, Watts PC. Applying the Anna Karenina principle for wild animal gut microbiota: Temporal stability of the bank vole gut microbiota in a disturbed environment. J Anim Ecol 2020; 89:2617-2630. [DOI: 10.1111/1365-2656.13342] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/10/2020] [Indexed: 12/19/2022]
Affiliation(s)
| | - Eugene Tukalenko
- Ecology and Genetics University of Oulu Oulu Finland
- National Research Center for Radiation Medicine of the National Academy of Medical Science Kyiv Ukraine
| | | | - Kati Kivisaari
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Sergii Masiuk
- National Research Center for Radiation Medicine of the National Academy of Medical Science Kyiv Ukraine
- Ukrainian Radiation Protection Institute Kyiv Ukraine
| | - Zbyszek Boratyński
- CIBIO‐InBIO Associate Laboratory Research Center in Biodiversity and Genetic ResourcesUniversity of Porto Vairão Portugal
| | - Timothy A. Mousseau
- Department of Biological Sciences University of South Carolina Columbia SC USA
| | - Gennadi Milinevsky
- Space Physics Laboratory Taras Shevchenko National University of Kyiv Kyiv Ukraine
- College of Physics International Center of Future Science Jilin University Changchun China
| | - Tapio Mappes
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Phillip C. Watts
- Ecology and Genetics University of Oulu Oulu Finland
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
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Rioux È, Pelletier F, St-Laurent MH. From diet to hair and blood: empirical estimation of discrimination factors for C and N stable isotopes in five terrestrial mammals. J Mammal 2020. [DOI: 10.1093/jmammal/gyaa108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AbstractCarbon and nitrogen stable isotope ratios are used widely to describe wildlife animal diet composition and trophic interactions. To reconstruct consumer diet, the isotopic differences between consumers and their diet items—called the trophic discrimination factor (TDF)—must be known. Proxies of diet composition are sensitive to the accuracy of TDFs. However, specific TDFs are still missing for many species and tissues because only a few controlled studies have been carried out on captive animals. The aim of this study was to estimate TDFs for hair and blood for carbon and nitrogen stable isotopes for caribou, moose, white-tailed deer, eastern coyote, and black bear. We obtained stable isotope ratios for diet items, hair, and blood samples, of 21 captive adult mammals. Diet–tissue discrimination factors for carbon in hair (∆ 13CLE) ranged from 0.96‰ to 3.72‰ for cervids, 3.01‰ to 3.76‰ for coyote, and 5.15‰ to 6.35‰ for black bear, while nitrogen discrimination factors (∆ 15N) ranged from 2.58‰ to 5.95‰ for cervids, 2.90‰ to 3.13‰ for coyote, and 4.48‰ to 5.44‰ for black bear. The ∆ 13CLE values in coyote blood components ranged from 2.20‰ to 2.69‰ while ∆ 15N ranged from 3.30‰ to 4.41‰. In caribou serum, ∆ 13CLE reached 3.34 ± 1.28‰ while ∆ 15N reached 5.02 ± 0.07‰. The TDFs calculated in this study will allow the evaluation of diet composition and trophic relationships between these five mammal species and will have important implications for the study of endangered caribou populations for which the use of noninvasive tissue sampling is highly relevant.
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Affiliation(s)
- Ève Rioux
- Centre for Northern Studies & Centre for Forest Research, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, allée des Ursulines, Rimouski, Québec, Canada
| | - Fanie Pelletier
- Centre for Northern Studies, Département de Biologie, Université de Sherbrooke, boul. de l’Université, Sherbrooke, Québec, Canada
| | - Martin-Hugues St-Laurent
- Centre for Northern Studies & Centre for Forest Research, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, allée des Ursulines, Rimouski, Québec, Canada
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Mantha OL, Huneau JF, Mathé V, Hermier D, Khodorova N, Mariotti F, Fouillet H. Differential changes to splanchnic and peripheral protein metabolism during the diet-induced development of metabolic syndrome in rats. Am J Physiol Endocrinol Metab 2020; 319:E175-E186. [PMID: 32459526 DOI: 10.1152/ajpendo.00061.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is known about the effects of the development of metabolic syndrome (MS) on protein and amino acid (AA) metabolism. During this study, we took advantage of the variability in interindividual susceptibility to high fat diet-induced MS to study the relationships between MS, protein synthesis, and AA catabolism in multiple tissues in rats. After 4 mo of high-fat feeding, an MS score (ZMS) was calculated as the average of the z-scores for individual MS components [weight, adiposities, homeostasis model for the assessment of insulin resistance (HOMA-IR), and triglycerides]. In the small intestine, liver, plasma, kidneys, heart, and muscles, tissue protein synthesis was measured by 2H2O labeling, and we evaluated the proportion of tissue AA catabolism (relative to protein synthesis) and nutrient routing to nonindispensable AAs in tissue proteins using natural nitrogen and carbon isotopic distances between tissue proteins and nutrients (Δ15N and Δ13C), respectively. In the liver, protein mass and synthesis increased, whereas the proportion of AA catabolism decreased with ZMS. By contrast, in muscles, we found no association between ZMS and protein mass, protein synthesis (except for a weak positive association in the gastrocnemius muscle only), and proportion of AA catabolism. The development of MS was also associated with altered metabolic flexibility and fatty acid oxidation, as shown by less routing of dietary lipids to nonindispensable AA synthesis in liver and muscle. In conclusion, MS development is associated with a greater gain of both fat and protein masses, with higher protein anabolism that mainly occurs in the liver, whereas muscles probably develop anabolic resistance due to insulin resistance.
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Affiliation(s)
- O L Mantha
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - J-F Huneau
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - V Mathé
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - D Hermier
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - N Khodorova
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - F Mariotti
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - H Fouillet
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
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20
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Krause DJ, Goebel ME, Kurle CM. Leopard seal diets in a rapidly warming polar region vary by year, season, sex, and body size. BMC Ecol 2020; 20:32. [PMID: 32493329 PMCID: PMC7271520 DOI: 10.1186/s12898-020-00300-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 05/23/2020] [Indexed: 11/21/2022] Open
Abstract
Background Resolving the preferred prey items and dietary proportions of leopard seals is central to understanding food-web dynamics in the rapidly-warming Antarctic Peninsula region. Previous studies have identified a wide range of prey items; however, due to anecdotal or otherwise limited information, leopard seal diets remain unresolved by seal sex, individual, body size, region, and season. Over the 2013, 2014, and 2017 field seasons we collected scat, tissue samples (red blood cells and plasma; n = 23) for stable isotope analyses, and previously-reported animal-borne video from 19 adult leopard seals foraging near mesopredator breeding colonies at Cape Shirreff, Livingston Island. We summarized a priori diet information from scat and video analysis and applied a three-isotope (δ13C, δ15N, δ34S), four-source (fish, fur seal, krill, penguin) Bayesian mixing model to examine temporal variability in both prey sources and leopard seal tissues. Results The austral spring diets of males and females focused on Antarctic krill (31.7–38.0%), notothen fish (31.6–36.5%), and penguin (24.4–26.9%) and were consistent across all 3 years. Several lines of evidence suggest the transition to summer foraging was distinct for males and females. Female diets transitioned rapidly to higher δ15N values (+2.1‰), indicating increased consumption of penguin (29.5–46.2%) and energy-dense Antarctic fur seal pup (21.3–37.6%). Conclusions The seasonal increase in leopard seal δ15N values, and thus fur seal in their diet, was predictably related to larger body size; it may also be forcing reductions to the largest Antarctic fur seal colony in the Antarctic Peninsula. Our ensemble sampling approach reduces historical biases in monitoring marine apex predator diets. Further, our results are necessary to best inform regional fisheries management planning.
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Affiliation(s)
- Douglas J Krause
- Antarctic Ecosystem Research Division, NOAA Fisheries-Southwest Fisheries Science Center, 8901 La Jolla Shores Dr., La Jolla, CA, USA.
| | - Michael E Goebel
- Antarctic Ecosystem Research Division, NOAA Fisheries-Southwest Fisheries Science Center, 8901 La Jolla Shores Dr., La Jolla, CA, USA
| | - Carolyn M Kurle
- Divsion of Biological Sciences, University of California San Diego, 9500 Gilman Dr., La Jolla, CA, USA
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21
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Naganuma T, Koike S, Nakashita R, Kozakai C, Yamazaki K, Furusaka S, Kaji K. Age- and Sex-Associated Differences in the Diet of the Asian Black Bear: Importance of Hard Mast and Sika Deer. MAMMAL STUDY 2020. [DOI: 10.3106/ms2019-0051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Tomoko Naganuma
- Laboratory of Forest Conservation Biology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Shinsuke Koike
- Laboratory of Forest Conservation Biology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Rumiko Nakashita
- Wildlife Ecology Laboratory, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Chinatsu Kozakai
- Wildlife Management Laboratory, Central Region Agricultural Research Center, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8666, Japan
| | - Koji Yamazaki
- Laboratory of Forest Ecology, Department of Forest Science, Faculty of Regional Environmental Science, Tokyo University of Agriculture, Setagaya, Tokyo 156-8502, Japan
| | - Shino Furusaka
- Laboratory of Forest Conservation Biology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Koichi Kaji
- Laboratory of Wildlife Management, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
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22
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Jacquier M, Simon L, Ruette S, Vandel JM, Hemery A, Devillard S. Isotopic evidence of individual specialization toward free-ranging chickens in a rural population of red foxes. EUR J WILDLIFE RES 2020. [DOI: 10.1007/s10344-019-1352-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kudo Y, Wada E. Ratio of naturally retained 15N to 13C in rat brain regions as a marker of brain function and activity. Neurosci Res 2020; 160:32-42. [PMID: 31931028 DOI: 10.1016/j.neures.2020.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 12/18/2019] [Accepted: 01/09/2020] [Indexed: 11/17/2022]
Abstract
Our aim in the present study was to clarify the activity-dependent and function-associated retention of stable isotopes (SIs) in rat brain regions. We measured regional distributions of the natural stable isotopes 15N and 13C in brain using a mass spectrometer with a dual inlet system and a double collector for ratiometry, and compared them with distributions obtained from internal organs and skeletal muscle. Although levels of 15N and 13C were very high in brain regions of prenatal rats, and robustly decreased after birth, developmental changes in brain regions became obvious when the ratio of 15N to 13C (abbreviated as 15N/13C) in each brain region was compared. A high correlation was observed between free motor activity and 15N/13C in the hippocampus, cerebrum, and striatum. A significantly higher 15N/13C was also observed in the hippocampus and striatum of rats with higher intelligence, which was evaluated by radial maze learning. Furthermore, 15N/13C in brain regions of trained rats were significantly higher than those of untrained age-matched rats. Our study suggests that the 15N/13C in a specific brain region may reflect the physiological feature of the region. This ratio may hence be applicable as a maker for pathological research on undiagnosed brain diseases.
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Affiliation(s)
- Yoshihisa Kudo
- Department of Anesthesiology, Tokyo Medical University Hachioji Medical Center, 1163 Tatemachi, Hachioji, Tokyo, 193-0998, Japan.
| | - Eitaro Wada
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-31-1 Sugesengoku, Tama-ku, Kawasaki, Kanagawa, 214-0006, Japan.
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24
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Lenzi J, González-Bergonzoni I, Machín E, Pijanowski B, Flaherty E. The impact of anthropogenic food subsidies on a generalist seabird during nestling growth. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:546-553. [PMID: 31216509 DOI: 10.1016/j.scitotenv.2019.05.485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/23/2019] [Accepted: 05/31/2019] [Indexed: 06/09/2023]
Abstract
Anthropogenic food subsidies, such as refuse, are an important driver of animal population changes and gulls heavily forage on this food source. Foraging on refuse during the rearing period could affect the acquisition of resources with potential demographic consequences. Using conventional diet analysis and stable isotopes of δ13C and δ15N of blood of Kelp Gull (Larus dominicanus) nestlings, we studied the variation of the chick growth in response to foraging on refuse on a reproductive colony in the Rio de la Plata Estuary in Uruguay. Using Bayesian mixing models on isotopic data, we estimated the proportion and variation of natural food and refuse in the diet of nestlings. Then, we modelled the variation between the mean posterior densities of the food sources and their standard deviation with the nestling morphometric measurements of different sizes. We found that refuse was gradually delivered to Kelp Gull nestlings during the chick rearing period. Additionally, variation of refuse incorporated into nestling tissues increased with nestlings' size. We propose that parents use more isotopically unique food sources during the nestling growth thereby increasing isotopic diversity. This study highlights the need to improve the current waste management system, which is being reviewed in Uruguay. We believe that decision makers should consider the results of this study, which show that refuse is directly impacting coastal ecosystems through mechanisms poorly explored by the environmental sciences.
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Affiliation(s)
- Javier Lenzi
- Centro de Investigación y Conservación Marina - CICMAR, Avenida Giannattasio Km 30.5, Canelones 15008, Uruguay; Purdue University, Department of Forestry and Natural Resources, 715 West State Street, West Lafayette, IN 47907, United States; Purdue University, Ecological Sciences and Engineering Program, 715 West State Street, West Lafayette, IN 47907, United States.
| | - Iván González-Bergonzoni
- Departamento del Agua CENUR Ltoral Norte sede Paysandú, Universidad de la República, Ruta 3 Km 363 EEMAC, Paysandú 60000, Uruguay; Departamento de Ecología y Biología Evolutiva, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Montevideo, Uruguay
| | - Emanuel Machín
- Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
| | - Bryan Pijanowski
- Purdue University, Department of Forestry and Natural Resources, 715 West State Street, West Lafayette, IN 47907, United States
| | - Elizabeth Flaherty
- Purdue University, Department of Forestry and Natural Resources, 715 West State Street, West Lafayette, IN 47907, United States
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Kesäniemi J, Jernfors T, Lavrinienko A, Kivisaari K, Kiljunen M, Mappes T, Watts PC. Exposure to environmental radionuclides is associated with altered metabolic and immunity pathways in a wild rodent. Mol Ecol 2019; 28:4620-4635. [PMID: 31498518 PMCID: PMC6900138 DOI: 10.1111/mec.15241] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/26/2019] [Accepted: 08/12/2019] [Indexed: 12/20/2022]
Abstract
Wildlife inhabiting environments contaminated by radionuclides face putative detrimental effects of exposure to ionizing radiation, with biomarkers such as an increase in DNA damage and/or oxidative stress commonly associated with radiation exposure. To examine the effects of exposure to radiation on gene expression in wildlife, we conducted a de novo RNA sequencing study of liver and spleen tissues from a rodent, the bank vole Myodes glareolus. Bank voles were collected from the Chernobyl Exclusion Zone (CEZ), where animals were exposed to elevated levels of radionuclides, and from uncontaminated areas near Kyiv, Ukraine. Counter to expectations, we did not observe a strong DNA damage response in animals exposed to radionuclides, although some signs of oxidative stress were identified. Rather, exposure to environmental radionuclides was associated with upregulation of genes involved in lipid metabolism and fatty acid oxidation in the livers - an apparent shift in energy metabolism. Moreover, using stable isotope analysis, we identified that fur from bank voles inhabiting the CEZ had enriched isotope values of nitrogen: such an increase is consistent with increased fatty acid metabolism, but also could arise from a difference in diet or habitat between the CEZ and elsewhere. In livers and spleens, voles inhabiting the CEZ were characterized by immunosuppression, such as impaired antigen processing, and activation of leucocytes involved in inflammatory responses. In conclusion, exposure to low dose environmental radiation impacts pathways associated with immunity and lipid metabolism, potentially as a stress-induced coping mechanism.
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Affiliation(s)
- Jenni Kesäniemi
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Toni Jernfors
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Anton Lavrinienko
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Kati Kivisaari
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Mikko Kiljunen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Phillip C Watts
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland.,Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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26
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Silva MA, Borrell A, Prieto R, Gauffier P, Bérubé M, Palsbøl PJ, Colaço A. Stable isotopes reveal winter feeding in different habitats in blue, fin and sei whales migrating through the Azores. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181800. [PMID: 31598219 PMCID: PMC6731742 DOI: 10.1098/rsos.181800] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Knowing the migratory movements and behaviour of baleen whales is fundamental to understanding their ecology. We compared δ15N and δ13C values in the skin of blue (Balaenoptera musculus), fin (Balaenoptera physalus) and sei (Balaenoptera borealis) whales sighted in the Azores in spring with the values of potential prey from different regions within the North Atlantic using Bayesian mixing models to investigate their trophic ecology and migration patterns. Fin whale δ15N values were higher than those recorded in blue and sei whales, reflecting feeding at higher trophic levels. Whales' skin δ15N and δ13C values did not reflect prey from high-latitude summer foraging grounds; instead mixing models identified tropical or subtropical regions as the most likely feeding areas for all species during winter and spring. Yet, differences in δ13C values among whale species suggest use of different regions within this range. Blue and sei whales primarily used resources from the Northwest African upwelling and pelagic tropical/subtropical regions, while fin whales fed off Iberia. However, determining feeding habitats from stable isotope values remains difficult. In conclusion, winter feeding appears common among North Atlantic blue, fin and sei whales, and may play a crucial role in determining their winter distribution. A better understanding of winter feeding behaviour is therefore fundamental for the effective conservation of these species.
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Affiliation(s)
- Mónica A. Silva
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
| | - Asunción Borrell
- Institute of Biodiversity Research (IRBio) & Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Rui Prieto
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
| | - Pauline Gauffier
- Institute of Biodiversity Research (IRBio) & Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Martine Bérubé
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Centre for Coastal Studies, Provincetown, MA 02657, USA
| | - Per J. Palsbøl
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Centre for Coastal Studies, Provincetown, MA 02657, USA
| | - Ana Colaço
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
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27
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Natural Isotope Abundances of Carbon and Nitrogen in Tissue Proteins and Amino Acids as Biomarkers of the Decreased Carbohydrate Oxidation and Increased Amino Acid Oxidation Induced by Caloric Restriction under a Maintained Protein Intake in Obese Rats. Nutrients 2019; 11:nu11051087. [PMID: 31100870 PMCID: PMC6567081 DOI: 10.3390/nu11051087] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/10/2019] [Accepted: 05/14/2019] [Indexed: 12/14/2022] Open
Abstract
A growing body of evidence supports a role for tissue-to-diet 15N and 13C discrimination factors (Δ15N and Δ13C), as biomarkers of metabolic adaptations to nutritional stress, but the underlying mechanisms remain poorly understood. In obese rats fed ad libitum or subjected to gradual caloric restriction (CR), under a maintained protein intake, we measured Δ15N and Δ13C levels in tissue proteins and their constitutive amino acids (AA) and the expression of enzymes involved in the AA metabolism. CR was found to lower protein mass in the intestine, liver, heart and, to a lesser extent, some skeletal muscles. This was accompanied by Δ15N increases in urine and the protein of the liver and plasma, but Δ15N decreases in the proteins of the heart and the skeletal muscles, alongside Δ13C decreases in all tissue proteins. In Lys, Δ15N levels rose in the plasma, intestine, and some muscles, but fell in the heart, while in Ala, and to a lesser extent Glx and Asx, Δ13C levels fell in all these tissues. In the liver, CR was associated with an increase in the expression of genes involved in AA oxidation. During CR, the parallel rises of Δ15N in urine, liver, and plasma proteins reflected an increased AA catabolism occurring at the level of the liver metabolic branch point, while Δ15N decreases in cardiac and skeletal muscle proteins indicated increased protein and AA catabolism in these tissues. Thus, an increased protein and AA catabolism results in opposite Δ15N effects in splanchnic and muscular tissues. In addition, the Δ13C decrease in all tissue proteins, reflects a reduction in carbohydrate (CHO) oxidation and routing towards non-indispensable AA, to achieve fuel economy.
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28
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Clark CT, Horstmann L, Misarti N. Lipid normalization and stable isotope discrimination in Pacific walrus tissues. Sci Rep 2019; 9:5843. [PMID: 30971722 PMCID: PMC6458160 DOI: 10.1038/s41598-019-42095-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/11/2019] [Indexed: 11/09/2022] Open
Abstract
Analysis of stable carbon and nitrogen isotope values (δ13C and δ15N) of animal tissues can provide important information about diet, physiology, and movements. Interpretation of δ13C and δ15N values, however, is influenced by factors such as sample lipid content, tissue-specific isotope discrimination, and tissue turnover rates, which are typically species- and tissue-specific. In this study, we generated lipid normalization models for δ13C and investigated the effects of chemical lipid extractions on δ13C and δ15N in Pacific walrus (Odobenus rosmarus divergens) muscle, liver, and skin. We also evaluated tissue-specific isotope discrimination in walrus muscle, liver, skin, and bone collagen. Mean δ13Clipid-free of skin and bone collagen were similar, as were mean δ15N of muscle and liver. All other tissues differed significantly for both isotopes. Differences in δ13Clipid-free and δ15N among tissues agreed with published estimates of marine mammal tissue-specific isotope discrimination factors, with the exception of skin. The results of this work will allow researchers to gain a clearer understanding of walrus diet and the structure of Arctic food webs, while also making it possible to directly compare the results of contemporary walrus isotope research with those of historic and paleoecological studies.
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Affiliation(s)
- Casey T Clark
- Water and Environmental Research Center, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska, 99775-5860, USA. .,College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 2150 Koyukuk Drive, Fairbanks, Alaska, 99775-7220, USA.
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 2150 Koyukuk Drive, Fairbanks, Alaska, 99775-7220, USA
| | - Nicole Misarti
- Water and Environmental Research Center, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska, 99775-5860, USA
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29
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Derbridge JJ, Koprowski JL. Experimental removals reveal dietary niche partitioning facilitates coexistence between native and introduced species. Ecol Evol 2019; 9:4065-4077. [PMID: 31015988 PMCID: PMC6467861 DOI: 10.1002/ece3.5036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 01/13/2019] [Accepted: 02/07/2019] [Indexed: 11/09/2022] Open
Abstract
Niche overlap between native species and ecologically similar invaders can lead to competitive exclusion of threatened native species, but if two such species also co-occur naturally elsewhere, interactions between native and introduced populations may mirror coevolved niche partitioning that reduces competition and promotes coexistence.A single, insular population of Fremont's squirrel (Tamiasciurus fremonti) the Mount Graham red squirrel (MGRS; T. f. grahamensis) in the Pinaleño Mountains, Arizona, USA, is critically endangered and resource competition with introduced Abert's squirrels (Sciurus aberti) may threaten its long-term persistence. The species are naturally synoptic in other mountain sites, and both consume diets comprised primarily of conifer seeds and fungi.We conducted experimental removals of introduced Abert's squirrels and used stable isotope analysis of diets before and after removals, and of diets in naturally syntopic populations to test the hypothesis that dietary niche partitioning can facilitate coexistence between native and introduced species. We also developed a novel approach to determine the influence of fluctuating food availability on carbon enrichment in consumers.Mount Graham red squirrels and introduced Abert's squirrels partitioned the dietary niche similarly to naturally syntopic populations. Removals had no apparent effect. Diet of MGRS was more closely linked to availability of resources than to presence of Abert's squirrels.Flexible dietary niche of introduced Abert's squirrels may have allowed them to exploit a resource opportunity in syntopy with MGRS. Variable food production of MGRS habitat may intensify competition in poor years, and territorial defense against non-native Abert's squirrels likely imposes fitness costs on individual MGRS. Similarity in our model species' diets may make MGRS more vulnerable to competition if climate change eliminates the advantages of larder-hoarding. Where introduced populations of ecologically similar species are better adapted to changing conditions, they may ultimately replace southern peripheral populations of native species.
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Affiliation(s)
| | - John L. Koprowski
- School of Natural Resources and the EnvironmentUniversity of ArizonaTucsonArizona
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30
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Richardson KM, Iverson JB, Kurle CM. Marine subsidies likely cause gigantism of iguanas in the Bahamas. Oecologia 2019; 189:1005-1015. [PMID: 30850885 DOI: 10.1007/s00442-019-04366-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/19/2019] [Indexed: 11/29/2022]
Abstract
We utilized natural experiment opportunities presented by differential conditions (presence/absence of seabirds and invasive species) on cays in the Bahamas to study whether interisland variations in food resources contributed to gigantism in Allen Cays Rock Iguanas (Cyclura cychlura inornata). We analyzed the stable carbon (δ13C) and nitrogen (δ15N) isotope values from iguana tissues and resources from each island food web to test the predictions that (1) food webs on islands with seabirds exhibit the influence of marine subsidies from seabird guano, whereas those from non-seabird islands do not, and (2) size differences in iguanas among cays were due to either (a) supplemental food availability from mice and/or seabird carcasses killed by barn owls (Tyto alba) and/or (b) access to more nutrient-rich vegetation fertilized by seabird guano. Food web components from the seabird island (Allen Cay) had 5-9‰ higher δ15N values than those on the other cays and Allen Cay plants contained nearly two times more nitrogen. Bayesian stable isotope mixing models indicated that C3 plants dominated iguana diets on all islands and showed no evidence for consumption of mice or shearwaters. The iguanas on Allen Cay were ~ 2 times longer (48.3 ± 11.6 cm) and ~ 6 times heavier (5499 ± 2847 g) than iguanas on other cays and this was likely from marine-derived subsidies from seabird guano which caused an increase in nitrogen concentration in the plants and a resultant increase in the δ15N values across the entire food web relative to non-seabird islands.
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Affiliation(s)
- Kristen M Richardson
- Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego, La Jolla, CA, 92093-0116, USA
| | - John B Iverson
- Department of Biology, Earlham College, Richmond, IN, 47374, USA
| | - Carolyn M Kurle
- Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego, La Jolla, CA, 92093-0116, USA.
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31
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Javornik J, Hopkins JB, Zavadlav S, Levanič T, Lojen S, Polak T, Jerina K. Effects of ethanol storage and lipids on stable isotope values in a large mammalian omnivore. J Mammal 2019. [DOI: 10.1093/jmammal/gyy187] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jernej Javornik
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
| | - John B Hopkins
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- School of Biodiversity Conservation, Unity College, Unity, ME, USA
| | - Saša Zavadlav
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Yield and Silviculture, Slovenian Forestry Institute, Večna pot, Ljubljana, Slovenia
| | - Tom Levanič
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Yield and Silviculture, Slovenian Forestry Institute, Večna pot, Ljubljana, Slovenia
| | - Sonja Lojen
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta, Ljubljana, Slovenia
- School of Environmental Sciences, University of Nova Gorica, Lanthieri mansion, Glavni,Vipava, Slovenia
| | - Tomaž Polak
- Biotechnical Faculty, Department of Food Science and Technology, University of Ljubljana, Jamnikarjeva, Ljubljana, Slovenia
| | - Klemen Jerina
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
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32
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Service CN, Bateman AW, Adams MS, Artelle KA, Reimchen TE, Paquet PC, Darimont CT. Salmonid species diversity predicts salmon consumption by terrestrial wildlife. J Anim Ecol 2019; 88:392-404. [PMID: 30618046 PMCID: PMC6850012 DOI: 10.1111/1365-2656.12932] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/07/2018] [Indexed: 11/30/2022]
Abstract
Resource waves—spatial variation in resource phenology that extends feeding opportunities for mobile consumers—can affect the behaviour and productivity of recipient populations. Interspecific diversity among Pacific salmon species (Oncorhynchus spp.) creates staggered spawning events across space and time, thereby prolonging availability to terrestrial wildlife. We sought to understand how such variation might influence consumption by terrestrial predators compared with resource abundance and intra‐ and interspecific competition. Using stable isotope analysis, we investigated how the proportion of salmon in the annual diet of male black bears (Ursus americanus; n = 405) varies with species diversity and density of spawning salmon biomass, while also accounting for competition with sympatric black and grizzly bears (U. arctos horribilis), in coastal British Columbia, Canada. We found that the proportion of salmon in the annual diet of black bears was ≈40% higher in the absence of grizzly bears, but detected little effect of relative black bear density and salmon biomass density. Rather, salmon diversity had the largest positive effect on consumption. On average, increasing diversity from one salmon species to ~four (with equal biomass contributions) approximately triples the proportion of salmon in diet. Given the importance of salmon to bear life histories, this work provides early empirical support for how resource waves may increase the productivity of consumers at population and landscape scales. Accordingly, terrestrial wildlife management might consider maintaining not only salmon abundance but also diversity.
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Affiliation(s)
- Christina N Service
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada.,Spirit Bear Research Foundation, Klemtu, British Columbia, Canada
| | - Andrew W Bateman
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Salmon Coast Field Station, Echo Bay, British Columbia, Canada
| | - Megan S Adams
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
| | - Kyle A Artelle
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada.,Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Thomas E Reimchen
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Paul C Paquet
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
| | - Chris T Darimont
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
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33
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Lewis MC, Sealy JC. Coastal complexity: Ancient human diets inferred from Bayesian stable isotope mixing models and a primate analogue. PLoS One 2018; 13:e0209411. [PMID: 30571752 PMCID: PMC6301609 DOI: 10.1371/journal.pone.0209411] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/05/2018] [Indexed: 11/19/2022] Open
Abstract
An extensive ecological literature applies stable isotope mixing models to derive quantitative dietary reconstructions from isotope ratios of consumer tissues. While this approach works well for some organisms, it is challenging for consumers with complex, varied diets, including humans; indeed, many archaeologists have avoided the use of mixing models because uncertainties in model outputs are sufficiently large that the findings are not helpful in understanding ancient lifeways. Here, we exploit an unparalleled opportunity to evaluate the feasibility of dietary quantification in a nutritionally and isotopically complex context on the Cape Peninsula, South Africa. Delta values (δ13C and δ15N) of 213 indigenous food samples enable us to characterise four food groups: terrestrial plants, terrestrial vertebrates, marine invertebrates and marine vertebrates. A recent study of baboons that consumed marine and terrestrial foods provides insight into the relationship between such foods and consumer tissue isotopes. We use this information to refine our interpretation of δ15N and especially δ13C in bone collagen from 35 archaeological hunter-gatherers, achieving better estimates of the relative importance of marine and terrestrial foods in the diet than has hitherto been possible. Based on Bayesian stable isotope mixing model (SIMM) outputs, we infer that the trophic enrichment factor (TEF) for δ13Cbone collagen in these coastal humans is closer to +3 than +5‰. In the most 13C- and 15N-rich individuals, 65-98% of bone collagen (95% credible intervals) derived from marine foods. Conversely, in 13C and 15N-poor individuals, 7-44% of bone collagen derived from marine foods. The uncertainties discussed here highlight the need for caution when implementing SIMMs in studies of consumers with complex diets. To our knowledge, this work constitutes the most detailed and most tightly constrained study of this problem to date.
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Affiliation(s)
- Matthew C. Lewis
- Department of Archaeology, University of Cape Town, Cape Town, South Africa
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
| | - Judith C. Sealy
- Department of Archaeology, University of Cape Town, Cape Town, South Africa
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34
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Li CH, Roth JD, Detwiler JT. Isotopic turnover rates and diet-tissue discrimination depend on feeding habits of freshwater snails. PLoS One 2018; 13:e0199713. [PMID: 29975726 PMCID: PMC6033391 DOI: 10.1371/journal.pone.0199713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 06/12/2018] [Indexed: 11/18/2022] Open
Abstract
Estimates of animal diets and trophic structure using stable isotope analysis are strongly affected by diet-tissue discrimination and tissue turnover rates, yet these factors are often unknown for consumers because they must be measured using controlled-feeding studies. Furthermore, these parameters may be influenced by diet quality, growth, and other factors. We measured the effect of dietary protein content on diet-tissue discrimination and tissue turnover in three freshwater snail species. We fed lettuce to individually housed snails (n = 450 per species) for ten weeks, then half were switched to a high-protein diet. Isotopic values of muscle and gonad tissue were assessed at 48 and 80 days post-diet change. Snail discrimination factors varied by diet (low-protein > high-protein) and usually differed among species for both N and C, although species had similar carbon discrimination when fed the low-protein diet. Carbon turnover rates were similar among species for a given tissue type, but nitrogen turnover varied more among species. In addition, diet affected growth of species differently; some species grew larger on high-protein (H. trivolvis) while others grew larger on low-protein diet (Lymnaea spp.). These differences among species in growth influenced turnover rates, which were faster in the species with the highest growth rate following the diet switch from low to high-protein. Thus, growth is one of the main processes that affects tissue turnover, but growth and feeding preference did not affect diet-tissue discrimination, which was greater on low-protein than high-protein diets for all species regardless of growth performance. These results suggest that diet might influence two key parameters of stable isotope analysis differently.
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Affiliation(s)
- Chen-Hua Li
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - James D. Roth
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jillian T. Detwiler
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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35
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Early changes in tissue amino acid metabolism and nutrient routing in rats fed a high-fat diet: evidence from natural isotope abundances of nitrogen and carbon in tissue proteins. Br J Nutr 2018; 119:981-991. [PMID: 29502540 DOI: 10.1017/s0007114518000326] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Little is known about how diet-induced obesity and insulin resistance affect protein and amino acid (AA) metabolism in tissues. The natural relative abundances of the heavy stable isotopes of C (δ 13C) and N (δ 15N) in tissue proteins offer novel and promising biomarkers of AA metabolism. They, respectively, reflect the use of dietary macronutrients for tissue AA synthesis and the relative metabolic use of tissue AA for oxidation v. protein synthesis. In this study, δ 13C and δ 15N were measured in the proteins of various tissues in young adult rats exposed perinatally and/or fed after weaning with a normal- or a high-fat (HF) diet, the aim being to characterise HF-induced tissue-specific changes in AA metabolism. HF feeding was shown to increase the routing of dietary fat to all tissue proteins via non-indispensable AA synthesis, but did not affect AA allocation between catabolic and anabolic processes in most tissues. However, the proportion of AA directed towards oxidation rather than protein synthesis was increased in the small intestine and decreased in the tibialis anterior muscle and adipose tissue. In adipose tissue, the AA reallocation was observed in the case of perinatal or post-weaning exposure to HF, whereas in the small intestine and tibialis anterior muscle the AA reallocation was only observed after HF exposure that covered both the perinatal and post-weaning periods. In conclusion, HF exposure induced an early reorganisation of AA metabolism involving tissue-specific effects, and in particular a decrease in the relative allocation of AA to oxidation in several peripheral tissues.
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36
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Roswag A, Becker NI, Millesi E, Otto MS, Ruoss S, Sander M, Siutz C, Weinhold U, Encarnação JA. Stable isotope analysis as a minimal-invasive method for dietary studies on the highly endangered Common hamster (Cricetus cricetus). MAMMALIA 2018. [DOI: 10.1515/mammalia-2017-0097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
This study applied the analysis of stable isotope ratios as a minimally-invasive tool to estimate the diet of Cricetus cricetus for the first time. We took hair and food samples of three different populations of C. cricetus and analyzed stable carbon and nitrogen ratios. The stable isotope ratios in hamster hairs differed significantly within and between populations according to different sampling seasons and animal ages. Additionally, the isotopic signatures of potential food samples differed between sampling sites and food categories. The isotopic mixing models illustrated that diet composition varied with season and food availability. During the summer season hamsters living in agricultural areas mainly fed on green and ripe crop. In contrast to this, during the winter season ripe crop was the main food component for hamsters in agricultural areas while hamsters living in urban areas fed almost exclusively on nuts. These are, despite a wide variety of available food sources, most suitable for hoarding in the burrow. We conclude that stable isotope analysis of hamster hairs is an appropriate minimal-invasive method to investigate correlations between available and consumed food sources throughout the overall distribution of this species.
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Affiliation(s)
- Anna Roswag
- Mammalian Ecology Group , Department of Animal Ecology and Systematics , Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ) , 35392 Gießen , Germany
| | - Nina I. Becker
- Mammalian Ecology Group , Department of Animal Ecology and Systematics , Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ) , 35392 Gießen , Germany
- inatu.re, Institute for Applied Animal Ecology and Ecoinformatics, Im Brühl 2 , 35457 Lollar , Germany
| | - Eva Millesi
- Department of Behavioural Biology , University of Vienna, Althanstrasse 14 , 1090 Vienna , Austria
| | - Matthias S. Otto
- Mammalian Ecology Group , Department of Animal Ecology and Systematics , Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ) , 35392 Gießen , Germany
| | - Sara Ruoss
- Mammalian Ecology Group , Department of Animal Ecology and Systematics , Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ) , 35392 Gießen , Germany
| | - Marco Sander
- Institute for Faunistics, Silberne Bergstr. 24 , 69253 Heiligkreuzsteinach , Germany
| | - Carina Siutz
- Department of Behavioural Biology , University of Vienna, Althanstrasse 14 , 1090 Vienna , Austria
| | - Ulrich Weinhold
- Institute for Faunistics, Silberne Bergstr. 24 , 69253 Heiligkreuzsteinach , Germany
| | - Jorge A. Encarnação
- Mammalian Ecology Group , Department of Animal Ecology and Systematics , Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26 (IFZ) , 35392 Gießen , Germany
- inatu.re, Institute for Applied Animal Ecology and Ecoinformatics, Im Brühl 2 , 35457 Lollar , Germany
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Trapp SE, Smith WP, Flaherty EA. Diet and food availability of the Virginia northern flying squirrel (Glaucomys sabrinus fuscus): implications for dispersal in a fragmented forest. J Mammal 2017. [DOI: 10.1093/jmammal/gyx115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Turner Tomaszewicz CN, Seminoff JA, Price M, Kurle CM. Stable isotope discrimination factors and between-tissue isotope comparisons for bone and skin from captive and wild green sea turtles (Chelonia mydas). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1903-1914. [PMID: 28857312 PMCID: PMC5653449 DOI: 10.1002/rcm.7974] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE The ecological application of stable isotope analysis (SIA) relies on taxa- and tissue-specific stable carbon (Δ13 C) and nitrogen (Δ15 N) isotope discrimination factors, determined with captive animals reared on known diets for sufficient time to reflect dietary isotope ratios. However, captive studies often prohibit lethal sampling, are difficult with endangered species, and reflect conditions not experienced in the wild. METHODS We overcame these constraints and determined the Δ13 C and Δ15 N values for skin and cortical bone from green sea turtles (Chelonia mydas) that died in captivity and evaluated the utility of a mathematical approach to predict discrimination factors. Using stable carbon (δ13 C values) and nitrogen (δ15 N values) isotope ratios from captive and wild turtles, we established relationships between bone stable isotope (SI) ratios and those from skin, a non-lethally sampled tissue, to facilitate comparisons of SI ratios among studies using multiple tissues. RESULTS The mean (±SD) Δ13 C and Δ15 N values (‰) between skin and bone from captive turtles and their diet (non-lipid-extracted) were 2.3 ± 0.3 and 4.1 ± 0.4 and 2.1 ± 0.6 and 5.1 ± 1.1, respectively. The mathematically predicted Δ13 C and Δ15 N values were similar (to within 1‰) to the experimentally derived values. The mean δ15 N values from bone were higher than those from skin for captive (+1.0 ± 0.9‰) and wild (+0.8 ± 1.0‰) turtles; the mean δ13 C values from bone were lower than those from skin for wild turtles (-0.6 ± 0.9‰), but the same as for captive turtles. We used linear regression equations to describe bone vs skin relationships and create bone-to-skin isotope conversion equations. CONCLUSIONS For sea turtles, we provide the first (a) bone-diet SI discrimination factors, (b) comparison of SI ratios from individual-specific bone and skin, and (c) evaluation of the application of a mathematical approach to predict stable isotope discrimination factors. Our approach opens the door for future studies comparing different tissues, and relating SI ratios of captive to wild animals.
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Affiliation(s)
- Calandra N. Turner Tomaszewicz
- Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego, La Jolla, California 92093-0116, USA
- Southwest Fisheries Science Center, NOAA, National Marine Fisheries Service, La Jolla, California 92037, USA
| | - Jeffrey A. Seminoff
- Southwest Fisheries Science Center, NOAA, National Marine Fisheries Service, La Jolla, California 92037, USA
| | - Mike Price
- SeaWorld San Diego, San Diego, California 92109, USA
| | - Carolyn M. Kurle
- Division of Biological Sciences, Ecology, Behavior, and Evolution Section, University of California, San Diego, La Jolla, California 92093-0116, USA
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Hughes KL, Whiteman JP, Newsome SD. The relationship between dietary protein content, body condition, and Δ15N in a mammalian omnivore. Oecologia 2017; 186:357-367. [DOI: 10.1007/s00442-017-4010-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 11/09/2017] [Indexed: 11/29/2022]
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Lewis MC, West AG, O'Riain MJ. Isotopic assessment of marine food consumption by natural-foraging chacma baboons on the Cape Peninsula, South Africa. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 165:77-93. [PMID: 29076130 DOI: 10.1002/ajpa.23332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 08/14/2017] [Accepted: 09/18/2017] [Indexed: 11/10/2022]
Abstract
OBJECTIVES Stable isotope analysis has been used to investigate consumption of marine resources in a variety of terrestrial mammals, including humans, but not yet in extant nonhuman primates. We sought to test the efficacy of stable isotope analysis as a tool for such studies by comparing isotope- and observation-based estimates of marine food consumption by a troop of noncommensal, free-ranging chacma baboons. MATERIALS AND METHODS We determined δ13 C and δ15 N values of baboon hair (n = 9) and fecal samples (n = 144), and principal food items (n = 362). These values were used as input for diet models, the outputs of which were compared to observation-based estimates of marine food consumption. RESULTS Fecal δ13 C values ranged from -29.3‰ to -25.6‰. δ15 N values ranged from 0.9‰ to 6.3‰ and were positively correlated with a measure of marine foraging during the dietary integration period. Mean (± SD) δ13 C values of adult male and female baboon hairs were -21.6‰ (± 0.1) and -21.8‰ (± 0.3) respectively, and corresponding δ15 N values were 5.0‰ (± 0.3) and 3.9‰ (± 0.2). Models indicated that marine contributions were ≤10% of baboon diet within any season, and contributed ≤17% of dietary protein through the year. DISCUSSION Model output and observational data were in agreement, both indicating that despite their abundance in the intertidal region, marine foods comprised only a small proportion of baboon diet. This suggests that stable isotope analysis is a viable tool for investigating marine food consumption by natural-foraging primates in temperate regions.
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Affiliation(s)
- Matthew C Lewis
- Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa.,Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa.,Department of Archaeology, University of Cape Town, Rondebosch, 7701, South Africa
| | - Adam G West
- Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - M Justin O'Riain
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
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Gorokhova E. Individual growth as a non‐dietary determinant of the isotopic niche metrics. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12887] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elena Gorokhova
- Department of Environmental Science and Analytical ChemistryStockholm University Stockholm Sweden
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Selecting the best stable isotope mixing model to estimate grizzly bear diets in the Greater Yellowstone Ecosystem. PLoS One 2017; 12:e0174903. [PMID: 28493929 PMCID: PMC5426898 DOI: 10.1371/journal.pone.0174903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 03/17/2017] [Indexed: 11/19/2022] Open
Abstract
Past research indicates that whitebark pine seeds are a critical food source for Threatened grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE). In recent decades, whitebark pine forests have declined markedly due to pine beetle infestation, invasive blister rust, and landscape-level fires. To date, no study has reliably estimated the contribution of whitebark pine seeds to the diets of grizzlies through time. We used stable isotope ratios (expressed as δ13C, δ15N, and δ34S values) measured in grizzly bear hair and their major food sources to estimate the diets of grizzlies sampled in Cooke City Basin, Montana. We found that stable isotope mixing models that included different combinations of stable isotope values for bears and their foods generated similar proportional dietary contributions. Estimates generated by our top model suggest that whitebark pine seeds (35±10%) and other plant foods (56±10%) were more important than meat (9±8%) to grizzly bears sampled in the study area. Stable isotope values measured in bear hair collected elsewhere in the GYE and North America support our conclusions about plant-based foraging. We recommend that researchers consider model selection when estimating the diets of animals using stable isotope mixing models. We also urge researchers to use the new statistical framework described here to estimate the dietary responses of grizzlies to declines in whitebark pine seeds and other important food sources through time in the GYE (e.g., cutthroat trout), as such information could be useful in predicting how the population will adapt to future environmental change.
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Hobbie EA. Dietary protein content and tissue type control 13 C discrimination in mammals: an analytical approach. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:639-648. [PMID: 28155261 DOI: 10.1002/rcm.7830] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/30/2017] [Accepted: 01/30/2017] [Indexed: 06/06/2023]
Affiliation(s)
- Erik A Hobbie
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
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Reid REB, Koch PL. Isotopic ecology of coyotes from scat and road kill carcasses: A complementary approach to feeding experiments. PLoS One 2017; 12:e0174897. [PMID: 28369133 PMCID: PMC5378380 DOI: 10.1371/journal.pone.0174897] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/16/2017] [Indexed: 11/18/2022] Open
Abstract
Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasive method to gather short-term dietary information. We conducted three interrelated studies to validate the use of isotopic values from coyote scat: 1) we determined tissue-to-tissue apparent C and N isotope enrichment factors (ε13* and ε15*) for coyotes from road kill animals (n = 4); 2) we derived diet-to-scat isotope discrimination factors for coyotes; and 3) we used field collected coyote scats (n = 12) to compare estimates of coyote dietary proportions from stable isotope mixing models with estimates from two GFA techniques. Scat consistently had the lowest δ13C and δ15N values among the tissues sampled. We derived a diet-to-scat Δ13C value of -1.5‰ ± 1.6‰ and Δ15N value of 2.3‰ ± 1.3‰ for coyotes. Coyote scat δ13C and δ15N values adjusted for discrimination consistently plot within the isotopic mixing space created by known dietary items. In comparison with GFA results, we found that mixing model estimates of coyote dietary proportions de-emphasize the importance of small-bodied prey. Coyote scat δ13C and δ15N values therefore offer a relatively quick and non-invasive way to gain accurate dietary information.
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Affiliation(s)
- Rachel E. B. Reid
- Earth and Planetary Sciences Department, University of California, Santa Cruz, California, United States of America
- * E-mail:
| | - Paul L. Koch
- Earth and Planetary Sciences Department, University of California, Santa Cruz, California, United States of America
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The influence of sulfur and hair growth on stable isotope diet estimates for grizzly bears. PLoS One 2017; 12:e0172194. [PMID: 28248995 PMCID: PMC5332026 DOI: 10.1371/journal.pone.0172194] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 02/01/2017] [Indexed: 11/19/2022] Open
Abstract
Stable isotope ratios of grizzly bear (Ursus arctos) guard hair collected from bears on the lower Stikine River, British Columbia (BC) were analyzed to: 1) test whether measuring δ34S values improved the precision of the salmon (Oncorhynchus spp.) diet fraction estimate relative to δ15N as is conventionally done, 2) investigate whether measuring δ34S values improves the separation of diet contributions of moose (Alces alces), marmot (Marmota caligata), and mountain goat (Oreamnos americanus) and, 3) examine the relationship between collection date and length of hair and stable isotope values. Variation in isotope signatures among hair samples from the same bear and year were not trivial. The addition of δ34S values to mixing models used to estimate diet fractions generated small improvement in the precision of salmon and terrestrial prey diet fractions. Although the δ34S value for salmon is precise and appears general among species and areas, sulfur ratios were strongly correlated with nitrogen ratios and therefore added little new information to the mixing model regarding the consumption of salmon. Mean δ34S values for the three terrestrial herbivores of interest were similar and imprecise, so these data also added little new information to the mixing model. The addition of sulfur data did confirm that at least some bears in this system ate marmots during summer and fall. We show that there are bears with short hair that assimilate >20% salmon in their diet and bears with longer hair that eat no salmon living within a few kilometers of one another in a coastal ecosystem. Grizzly bears are thought to re-grow hair between June and October however our analysis of sectioned hair suggested at least some hairs begin growing in July or August, not June and, that hair of wild bears may grow faster than observed in captive bears. Our hair samples may have been from the year of sampling or the previous year because samples were collected in summer when bears were growing new hair. The salmon diet fraction increased with later hair collection dates, as expected if samples were from the year of sampling because salmon began to arrive in mid-summer. Bears that ate salmon had shorter hair and δ15N and δ34S values declined with hair length, also suggesting some hair samples were grown the year of sampling. To be sure to capture an entire hair growth period, samples must be collected in late fall. Early spring samples are also likely to be from the previous year but the date when hair begins to grow appears to vary. Choosing the longest hair available should increase the chance the hair was grown during the previous year and, maximize the period for which diet is measured.
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HAN H, WEI W, NIE Y, ZHOU W, HU Y, WU Q, WEI F. Distinctive diet-tissue isotopic discrimination factors derived from the exclusive bamboo-eating giant panda. Integr Zool 2016; 11:447-456. [DOI: 10.1111/1749-4877.12208] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Han HAN
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Wei WEI
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
| | - Yonggang NIE
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
| | - Wenliang ZHOU
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
| | - Yibo HU
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
| | - Qi WU
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
| | - Fuwen WEI
- Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
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Galván DE, Jañez J, Irigoyen AJ. Estimating tissue-specific discrimination factors and turnover rates of stable isotopes of nitrogen and carbon in the smallnose fanskate Sympterygia bonapartii (Rajidae). JOURNAL OF FISH BIOLOGY 2016; 89:1258-1270. [PMID: 27282324 DOI: 10.1111/jfb.13024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 04/11/2016] [Indexed: 06/06/2023]
Abstract
This study aimed to estimate trophic discrimination factors (TDFs) and metabolic turnover rates of nitrogen and carbon stable isotopes in blood and muscle of the smallnose fanskate Sympterygia bonapartii by feeding six adult individuals, maintained in captivity, with a constant diet for 365 days. TDFs were estimated as the difference between δ(13) C or δ(15) N values of the food and the tissues of S. bonapartii after they had reached equilibrium with their diet. The duration of the experiment was enough to reach the equilibrium condition in blood for both elements (estimated time to reach 95% of turnover: C t95%blood = 150 days, N t95%blood = 290 days), whilst turnover rates could not be estimated for muscle because of variation among samples. Estimates of Δ(13) C and Δ(15) N values in blood and muscle using all individuals were Δ(13) Cblood = 1·7‰, Δ(13) Cmuscle = 1·3‰, Δ(15) Nblood = 2·5‰ and Δ(15) Nmuscle = 1·5‰, but there was evidence of differences of c.0·4‰ in the Δ(13) C values between sexes. The present values for TDFs and turnover rates constitute the first evidence for dietary switching in batoids based on long-term controlled feeding experiments. Overall, the results showed that S. bonapartii has relatively low turnover rates and isotopic measurements would not track seasonal movements adequately. The estimated Δ(13) C values in S. bonapartii blood and muscle were similar to previous estimations for elasmobranchs and to generally accepted values in bony fishes (Δ(13) C = 1·5‰). For Δ(15) N, the results were similar to published reports for blood but smaller than reports for muscle and notably smaller than the typical values used to estimate trophic position (Δ(15) N c. 3·4‰). Thus, trophic position estimations for elasmobranchs based on typical Δ(15) N values could lead to underestimates of actual trophic positions. Finally, the evidence of differences in TDFs between sexes reveals a need for more targeted research.
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Affiliation(s)
- D E Galván
- Centro para el Estudio de Sistemas Marinos-Consejo Nacional de Investigaciones Científicas y Técnicas (CESIMAR-CONICET), Boulevard Brown 2915, (U9120ACV), Puerto Madryn, Chubut, Argentina
| | - J Jañez
- Aquarium Fundación Temaiken, Ruta 25, km 1 (1625) Escobar, Buenos Aires, Argentina
| | - A J Irigoyen
- Centro para el Estudio de Sistemas Marinos-Consejo Nacional de Investigaciones Científicas y Técnicas (CESIMAR-CONICET), Boulevard Brown 2915, (U9120ACV), Puerto Madryn, Chubut, Argentina
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50
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Busst GMA, Britton JR. High variability in stable isotope diet-tissue discrimination factors of two omnivorous freshwater fishes in controlled ex situ conditions. ACTA ACUST UNITED AC 2016; 219:1060-8. [PMID: 26896544 DOI: 10.1242/jeb.137380] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/27/2016] [Indexed: 11/20/2022]
Abstract
Diet-tissue discrimination factors (Δ(13)C and Δ(15)N) are influenced by variables including the tissues being analysed and the taxon of the consumer and its prey. Whilst differences in Δ(13)C and Δ(15)N are apparent between herbivorous and piscivorous fishes, there is less known for omnivorous fishes that consume plant and animal material. Here, the omnivorous cyprinid fishes Barbus barbus and Squalius cephalus were held in tank aquaria and exposed to three diets that varied in their constituents (plant based to fishmeal based) and protein content (13% to 45%). After 100 days and isotopic replacement in fish tissues to 98%, samples of the food items, and dorsal muscle, fin tissue and scales were analysed for δ(13)C and δ(15)N. For both species and all diets, muscle was always enriched in δ(15)N and depleted in δ(13)C compared with fin tissue and scales. Across the different diets, Δ(13)C ranged between 2.0‰ and 5.6‰ and Δ(15)N ranged between 2.0‰ and 6.9‰. The diet based on plant material (20% protein) always resulted in the highest discrimination factors for each tissue, whilst the diet based on fishmeal (45% protein) consistently resulted in the lowest. The discrimination factors produced by non-fish diets were comparatively high compared with values in the literature, but were consistent with general patterns for some herbivorous fishes. These outputs suggest that the diet-tissue discrimination factors of omnivorous fishes will vary considerably between animal and plant prey, and these specific differences need consideration in predictions of their diet composition and trophic position.
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Affiliation(s)
- Georgina M A Busst
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK
| | - J Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK
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