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Reid REB, Crowley BE, Haupt RJ. The prospects of poop: a review of past achievements and future possibilities in faecal isotope analysis. Biol Rev Camb Philos Soc 2023; 98:2091-2113. [PMID: 37438959 DOI: 10.1111/brv.12996] [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: 11/02/2021] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023]
Abstract
What can the stable isotope values of human and animal faeces tell us? This often under-appreciated waste product is gaining recognition across a variety of disciplines. Faecal isotopes provide a means of monitoring diet, resource partitioning, landscape use, tracking nutrient inputs and cycling, and reconstructing past climate and environment. Here, we review what faeces are composed of, their temporal resolution, and how these factors may be impacted by digestive physiology and efficiency. As faeces are often used to explore diet, we clarify how isotopic offsets between diet and faeces can be calculated, as well as some differences among commonly used calculations that can lead to confusion. Generally, faecal carbon isotope (δ13 C) values are lower than those of the diet, while faecal nitrogen isotope values (δ15 N) values are higher than in the diet. However, there is considerable variability both within and among species. We explore the role of study design and how limitations stemming from a variety of factors can affect both the reliability and interpretability of faecal isotope data sets. Finally, we summarise the various ways in which faecal isotopes have been applied to date and provide some suggestions for future research. Despite remaining challenges, faecal isotope data are poised to continue to contribute meaningfully to a variety of fields.
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Affiliation(s)
- Rachel E B Reid
- Department of Geosciences, Virginia Tech, 4044 Derring Hall, 926 West Campus Dr, Blacksburg, VA, 24061, USA
| | - Brooke Erin Crowley
- Department of Geosciences, University of Cincinnati, 500 Geology Physics Building, 345 Clifton Court, Cincinnati, OH, 45221-0013, USA
- Department of Anthropology, University of Cincinnati, 481 Braunstein Hall, Cincinnati, OH, 45221-0380, USA
| | - Ryan J Haupt
- National Youth Science Foundation, PO Box 3387, Charleston, WV, 25333-3387, USA
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Oelze VM, O'Neal I, Wittig RM, Kupczik K, Schulz-Kornas E, Hohmann G. A skew in poo: Biases in primate fecal isotope analysis and recommendations for standardized sample preparation. Am J Primatol 2023; 85:e23436. [PMID: 36239010 DOI: 10.1002/ajp.23436] [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: 05/09/2022] [Revised: 08/29/2022] [Accepted: 09/05/2022] [Indexed: 01/05/2023]
Abstract
Feces are a treasure trove in the study of animal behavior and ecology. Stable carbon and nitrogen isotope analysis allows to assess the dietary niches of elusive primate species and primate breastfeeding behavior. However, some fecal isotope data may unwillingly be biased toward the isotope ratios of undigested plant matter, requiring more consistent sample preparation protocols. We assess the impact of this potential data skew in 114 fecal samples of wild bonobos (Pan paniscus) by measuring the isotope differences (Δ13 C, Δ15 N) between bulk fecal samples containing larger particles (>1 mm) and filtered samples containing only small particles (<1 mm). We assess the influence of fecal carbon and nitrogen content (ΔC:N) and sample donor age (subadult, adult) on the resulting Δ13 C, Δ15 N values (n = 228). Additionally, we measure the isotope ratios in three systematically sieved fecal samples of chimpanzees (Pan troglodytes verus), with particle sizes ranging from 20 μm to 8 mm (n = 30). We found differences in fecal carbon and nitrogen content, with the smaller fecal fraction containing more nitrogen on average. While the Δ13 C values were small and not affected by age or ΔC:N, the Δ15 N values were significantly influenced by fecal ΔC:N, possibly resulting from the differing proportions of undigested plant macroparticles. Significant relationships between carbon stable isotope ratios (δ13 C) values and %C in large fecal fractions of both age groups corroborated this assessment. Δ15 N values were significantly larger in adults than subadults, which should be of concern in isotope studies comparing adult females with infants to assess breastfeeding. We found a random variation of up to 3.0‰ in δ13 C and 2.0‰ in nitrogen stable isotope ratios within the chimpanzee fecal samples separated by particle sizes. We show that particle size influences isotope ratios and propose a simple, cost-effective filtration method for primate feces to exclude larger undigested food particles from the analysis, which can easily be adopted by labs worldwide.
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Affiliation(s)
- Vicky M Oelze
- Anthropology Department, University of California, Santa Cruz, Santa Cruz, California, USA
| | - Isabella O'Neal
- Anthropology Department, University of California, Santa Cruz, Santa Cruz, California, USA
| | - Roman M Wittig
- Department of Human Behavior, Max Planck Institute for Evolutionary Anthropology, Ecology and Culture, Leipzig, Germany.,Institute for Cognitive Sciences, CNRS UMR5229 University Claude Bernard Lyon 1, Bron, France
| | - Kornelius Kupczik
- Department of Anthropology, Faculty of Social Sciences, University of Chile, Ñuñoa, Santiago de Chile, Chile.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Ellen Schulz-Kornas
- Department of Cariology, Endodontology and Periodontology, University of Leipzig, Leipzig, Germany
| | - Gottfried Hohmann
- Department of Human Behavior, Max Planck Institute for Evolutionary Anthropology, Ecology and Culture, Leipzig, Germany.,Max-Planck-Institute of Animal Behavior, Konstanz, Germany
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3
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A chimpanzee enamel-diet δ 13C enrichment factor and a refined enamel sampling strategy: Implications for dietary reconstructions. J Hum Evol 2021; 159:103062. [PMID: 34536662 DOI: 10.1016/j.jhevol.2021.103062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 08/01/2021] [Accepted: 08/01/2021] [Indexed: 11/24/2022]
Abstract
Reconstructing diets from stable carbon isotopic signals in enamel bioapatite requires the application of a δ13C enamel-diet enrichment factor, or the isotopic offset between diet and enamel, which has not been empirically determined for any primate. In this study, an enamel-diet enrichment factor (ε∗enamel-diet) of 11.8 ± 0.3‰ is calculated for chimpanzees (Pan troglodytes) at Ngogo in Kibale National Park, Uganda, based on a comprehensive isotopic assessment of previously analyzed dietary plant data and new isotopic analyses of enamel apatite. Different enamel sampling methods are evaluated to determine the potential influence of weaning on isotopic enamel values and dietary interpretations. The new chimpanzee enrichment factor and a sampling strategy that excludes teeth that formed before weaning completion are applied to all known chimpanzee δ13Cenamel data, either previously published or newly derived in this study, resulting in a dietary range of almost 6‰ across all chimpanzees sampled. This new chimpanzee enamel-diet enrichment factor is then used to reassess dietary reconstructions of 12 fossil hominin species whose isotopic enamel signatures have been determined. Results reveal hominin diets that are isotopically more positive than previously reconstructed, highlighting the widespread contribution of 13C-enriched C4/crassulacean acid metabolism (CAM) resources in fossil hominin diets and emphasizing the broad use of these resources during human evolution. These findings stress the importance of ascertaining and employing an appropriate enrichment factor for dietary reconstructions of specific taxa as well as standardizing the sampling protocol for tooth enamel in isotopic paleodietary reconstructions.
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Tsutaya T, Ogawa NO, Nomura T, Shimizu M, Ohkouchi N, Kuze N. Carbon and nitrogen stable isotopic offsets between diet and hair/feces in captive orangutans. Primates 2021; 62:945-954. [PMID: 34415484 DOI: 10.1007/s10329-021-00940-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
Estimating stable isotopic offset values is crucial for dietary reconstructions. Although research into stable isotope ecology of wild nonhuman primates is increasing overall, only a minority of studies involve laboratory experiments. This study is the first to report the carbon and nitrogen stable isotopic offset values in hair and feces of orangutans. During an experiment lasting 1 week, the weight of each consumed food item was recorded for each of six captive Bornean orangutan (Pongo pygmaeus) individuals. The food, hair, and fecal samples were collected for a few days, and their stable carbon and nitrogen isotope ratios were measured using an elemental analyzer/isotope ratio mass spectrometer. Subsamples of feces were treated with ethanol during the preservation process. Monte Carlo analyses showed that the 95% confidence intervals (CIs) of the carbon and nitrogen offset values between hair and diet were +0.9‰ to +3.9‰ and +2.3‰ to +4.5‰, respectively. The 95% CIs of the carbon and nitrogen offset values between feces and diet were -3.7‰ to -0.9‰ and +0.3‰ to +2.7‰, respectively. The effect of ethanol treatment on the stable isotope ratios of feces was unclear and inconclusive. The computed offset values of hair in captive orangutans are similar to those reported in other nonhuman primates, although those of feces showed greater interspecies variations. The offset values estimated in this study contribute to isotopic studies into the feeding ecology of free-ranging orangutans who are critically endangered in most wild settings.
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Affiliation(s)
- Takumi Tsutaya
- Department of Evolutionary Studies of Biosystems, the Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, 240-0193, Japan. .,Japan Agency for Marine-Earth Science and Technology, Biogeochemistry Research Center, Research Institute for Marine Resources Utilization, Natsushima 2-15, Yokosuka, Kanagawa, 237-0061, Japan.
| | - Nanako O Ogawa
- Japan Agency for Marine-Earth Science and Technology, Biogeochemistry Research Center, Research Institute for Marine Resources Utilization, Natsushima 2-15, Yokosuka, Kanagawa, 237-0061, Japan
| | - Toshiya Nomura
- Tama Zoological Park, Hodokubo 7-1-1, Hino, Tokyo, 191-0042, Japan
| | - Mika Shimizu
- Tama Zoological Park, Hodokubo 7-1-1, Hino, Tokyo, 191-0042, Japan.,Present address: Ikimonosha, Maya 714, Akaiwa, Okayama, 709-0825, Japan
| | - Naohiko Ohkouchi
- Japan Agency for Marine-Earth Science and Technology, Biogeochemistry Research Center, Research Institute for Marine Resources Utilization, Natsushima 2-15, Yokosuka, Kanagawa, 237-0061, Japan
| | - Noko Kuze
- Department of Anthropology, National Museum of Nature and Science, Amakubo 4-1-1, Tsukuba, Ibaraki, 305-0005, Japan
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Reitsema LJ, Jones CE, Gilbert HR, Fragaszy D, Izar P. Isotopic and elemental corroborates for wild bearded capuchin (Sapajus libidinosus) omnivorous dietary adaptation at Fazenda Boa Vista, Brazil. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8856. [PMID: 32526804 DOI: 10.1002/rcm.8856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/15/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE This study analyzes variability in the diets of wild bearded capuchin monkeys, Sapajus libidinosus, by analyzing stable carbon (δ13 C) and nitrogen (δ15 N) isotope ratios and elemental concentrations (%C and %N) of fecal samples and food items. Developing isotopic and elemental correlates for diets of habituated subjects is a necessary step towards applying similar methods to interpret diets of unhabituated or cryptic subjects. METHODS Fecal samples from wild capuchins and their foods were collected at Fazenda Boa Vista, Brazil. Fecal samples from laboratory-housed Sapajus spp. and their foods were analyzed to establish diet-feces offsets for δ13 C, δ15 N, %C, and %N. Samples were dried, powdered, and measured for isotopic and elemental values. A Bayesian mixing model commutes isotopic and elemental data from wild capuchins into likely proportions of different food categories. RESULTS The captive study shows small diet-feces spaces for Sapajus spp. of -0.8 ± 0.7‰ for δ13 C, -0.2 ± 0.4‰ for δ15 N, -6.1 ± 1.7% for %C, and -1.0 ± 0.6% for %N. The wild study shows omnivorous diets based on C3 , C4 , and CAM plants, and fauna. Subject diets are highly varied within and between days. Fecal data show age-related differences in diet and crop-raiding. There is no consistent isotopic or elemental difference between mothers and infants. CONCLUSIONS Fecal stable isotope and elemental evidence employed in a Bayesian mixing model reflects the highly varied diets of capuchin monkeys in an isotopically heterogeneous environment. The isotopic and elemental variability reported here will aid similar diet reconstructions among unhabituated subjects in the future, but precludes tracking weaning isotopically among capuchins in this environment.
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Affiliation(s)
| | - Caroline E Jones
- Department of Psychology, University of Georgia, Athens, GA, USA
| | - Hannah R Gilbert
- Department of Chemistry, University of Georgia, Athens, GA, USA
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Dorothy Fragaszy
- Department of Psychology, University of Georgia, Athens, GA, USA
| | - Patrícia Izar
- Department of Experimental Psychology, University of Sao Paulo, Sao Paulo, BRAZIL
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Crowley BE, Wultsch C, Kelly MJ. Does faecal matter reflect location? An initial assessment of isotopic variability between consumed prey remains and faecal matter for wild jaguars . ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2019; 55:478-498. [PMID: 31402710 DOI: 10.1080/10256016.2019.1648263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Faecal isotopic analysis may complement other non-invasive wildlife survey tools for monitoring landscape use by carnivores, such as motion-detecting cameras and non-invasive genetic sampling. We analysed carbon, nitrogen, and strontium isotopes in faecal matter produced by jaguars (Panthera onca) as well as bones from consumed prey at the Mountain Pine Ridge Forest Reserve (MPR) in Belize, Central America. The MPR is ideally suited for a spatial isotope study as vegetation and geology both vary considerably. The isotopic composition of faecal matter should reflect the habitat and geology where consumed prey lived. We used bone from consumed prey recovered from jaguar scats as a proxy for diet. Faecal matter and bone showed comparable spatial isotopic trends, suggesting that the isotopic composition of jaguar faeces can be used to detect foraging in different habitats (pine forest versus broadleaf forest) or on different geologies (Mesozoic carbonates; Palaeozoic granite, contact metamorphics, and metasediments). This result is reassuring as bones are not always present in carnivore scats. Studying landscape use by cryptic and wide-ranging carnivore species like jaguars remains challenging. Isotopic analysis of faecal matter complements the existing array of non-invasive spatial monitoring tools.
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Affiliation(s)
- Brooke E Crowley
- Department of Geology, University of Cincinnati , Cincinnati , OH , USA
- Department of Anthropology, University of Cincinnati , Cincinnati , OH , USA
| | - Claudia Wultsch
- Bioinformatics and Computational Genomics Laboratory, Hunter College, City University of New York , New York , NY , USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History , New York , NY , USA
- Department of Fish and Wildlife Conservation, Virginia Tech , Blacksburg , VA , USA
| | - Marcella J Kelly
- Department of Fish and Wildlife Conservation, Virginia Tech , Blacksburg , VA , USA
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8
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Wessling EG, Oelze VM, Eshuis H, Pruetz JD, Kühl HS. Stable isotope variation in savanna chimpanzees (Pan troglodytes verus) indicate avoidance of energetic challenges through dietary compensation at the limits of the range. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 168:665-675. [PMID: 30693959 DOI: 10.1002/ajpa.23782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/20/2018] [Accepted: 01/02/2019] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Food scarcity is proposed to be a limitation to chimpanzees at the limits of their range; however, such a constraint has never been investigated in this context. We investigated patterns of δ13 C and δ15 N variation along a latitudinal gradient at the northwestern West African chimpanzee (Pan troglodytes verus) range limit with the expectation that isotope ratios of chimpanzees at the range limit will indicate different dietary strategies or higher physiological constraints than chimpanzees further from the edge. MATERIALS AND METHODS We measured δ13 C and δ15 N values in hair (n = 81) and plant food (n = 342) samples from five chimpanzee communities located along a latitudinal gradient in Southeastern Senegal. RESULTS We found clear grouping patterns in hair δ13 C and δ15 N in the four southern sites compared to the northernmost site. Environmental baseline samples collected from these sites revealed overall higher plant δ15 N values at the northernmost site, but similar δ13 C values across sites. By accounting for environmental baseline, Δ13 C and Δ15 N values were clustered for all five sites relative to total Pan variation, but indicated a 13 C-enriched diet at the range limit. DISCUSSION Clustering in Δ13 C and Δ15 N values supports that strategic shifting between preferred and fallback foods is a likely ubiquitous but necessary strategy employed by these chimpanzees to cope with their environment, potentially allowing chimpanzees at their limits to avoid periods of starvation. These results also underline the necessity of accounting for local isotopic baseline differences during inter-site comparison.
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Affiliation(s)
- Erin G Wessling
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
| | - Vicky M Oelze
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Anthropology, University of California Santa Cruz, Santa Cruz, California
| | - Henk Eshuis
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Jill D Pruetz
- Department of Anthropology, Texas State University, San Marcos, Texas
| | - Hjalmar S Kühl
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
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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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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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